schil01-camper

Hi. I have a 87 Sunrader camper on a truck base with 2WD auto trans and dual tires on the back. The good 'ol stock 22re is pulling it as well as it can (slowly of course).
After a 250 mile round trip this last weekend I had to replace about 3/4 gallon of coolant and so I started trying to figure out why. The same coolant loss happened on the last trip too. Long story short is that it may be the head gasket starting to leak as I believe I'm getting some exhaust into my coolant. I was hoping that someone could confirm or refute this diagnosis before I commit to the dreaded head gasket procedure.

There has been no overheating problem but I noticed some coolant smell around the vehicle during the trip on one occasion but could not find a leak. At home I did a coolant system pressure test and cold (engine off) it holds 15 PSI for 15 minutes with no leaks. Plugs are all tan in color. No problem idling and it generally runs fine (though not as fast up the hills as I'd like :-) The overflow coolant in the reservoir is getting used up. No white smoke or sweet smell in the tailpipe. Oil is clean. When running I think I see some tiny bubbles in the coolant. I did the pressure test when idling at temp and it built up to 15 PSI over about 10 minutes. This suggests, I think, that the head gasket is leaking a bit, but just from exhaust into coolant. Funny thing is, I can't tell where the coolant is going. Maybe it's blowing past the cap in spurts and evaporating so I don't notice a leak that I can see. I don't see evidence of overflow from the reservoir in the engine compartment - reservoir was empty at the end of the trip. Possibly it's blowing through the reservoir, overflowing it (and evaporating off the engine compartment interior?), and then sucking all of the remaining coolant back into the radiator after it cools leaving the reservoir empty? Or maybe just blowing past the cap and never getting to the reservoir? If it were going out the exhaust I figured I'd see evidence on the plug and maybe smell it. I have not done any analysis to determine if exhaust/hydrocarbons can be detected in the coolant, which looks not quite clear but still decently green.

I have left it at idle for several hours today and there is no coolant blowing by the cap, but I have not done any further road driving since I returned. I think the coolant blow-by occurred during the trip when I hit a few hills and had to push it pretty hard for a short time. Perhaps the head gasket leak is just small now and under stress it reached a tipping point. Am I just being paranoid? In parallel with the coolant loss, the buildup of pressure to 15 PSI at idle in the cooling system with the pressure testing cap device is a key piece of evidence suggesting the head gasket. It should be down at 5 to 7-ish PSI. Maybe I have done this test poorly? I didn't drain the radiator so it was pretty full. A little liquid reached the cap part of the tester but not very much.

Also, I checked my t-stat and it's working properly. It's the dual-type and the small plug opens at about 175F and the big one at 180F (did the test in a pot of water on the stove). My jiggler is removed to allow some coolant to bypass as I had trouble with spikes when the heater was running last year. I think I have air in the cooling system now, though that may not be significant in this case.

I wasn't sure what test to do next so I thought I'd try out this forum that I've found so useful over the years. I was wondering if y'all have any insight into this situation or could make any recommendations. I could do a block test to confirm exhaust in the coolant, but if you have reason to think my head gasket diagnosis is wrong I'd be interested in hearing from you.

DallasTX

Not familiar with your model but some throttle body types have a coolant passage which apparently can leak coolant into the intake.

Definitely recommend using a block test kit to check for hydrocarbons in the radiator. Check your local auto parts store for the free loaners. In my area, Autozone, O'Reilly and Pepboys all have them. You have to buy the test fluid which is about $7.00 per bottle which will allow you to test multiple times if you desire to confirm the results (I definitely did). Just ensure you drain enough coolant to give a head space in the radiator to prevent drawing coolant into the tester. Being a little paranoid, I flushed the loaner with distilled water a couple times. Definitely did not want a false positive from the previous user drawing coolant into it.

I cannot comment on the pressure build at idle. It might be from head gasket blow-by, but possible also due to thermal expansion.

As bad a replacing the head gasket might be, at least catching it early minimizes the damage.

schil01-camper

Excellent suggestion about getting a loaner tool locally to do the combustion test. I have several options nearby.
Interesting hypothesis about the thermal expansion causing the high pressure reading. It seems possible, and it further underscores the importance of doing the block test. If the block test is positive then that pretty much nails it down as the head gasket going bad. If it's inconclusive then I'll have to look for some other way to determine if it is or is not the head gasket causing the coolant loss.

DallasTX

If you have access to an inspection camera with a head small enough to file down the spark plug bore, it might also help you determine if the head gasket is leaking, but recommend the block test first because it is cheap, easy and effective. I am not a mechanic, so only speaking from personal experience. If there is a small coolant leak into the cylinder, I think the top of the piston will be cleaner than others. As an example, look at the #6 piston top in the attached photo as compared to the #4 and 5. I have never used the inspection camera method, so not sure if the resolution would be sufficient as compared to looking at it when the head is off.

In the for what it is worth department, you might check on-line first to ensure the local parts store has the block test kit. I did not know it was available as a loaner tool and was shopping for one. I figured $40 to determine if the head gasket is blown is money well spent.

Found a local Pep Boys which showed one on-hand on-line Went to the store and the guy had no flipping clue what it was. I had to bring it up on their website and show him he had one in stock. After 15 minutes of searching the store, he found it in the service department, but said it was used/broken, but called another store several miles away which showed they had one available.

Stopped at O’Reilly’s on way home and asked. The young man also had no clue what a block test kit was, and frankly my only knowledge was from forums like this and the picture I saw on Amazon and Pep Boys website. He searched the computer a bit without success, then asked this boss who said yes they sell them and told him what key search words to use. As he was searching, I happened to look down at the laminated loaner tool mat and saw a picture of the test kit and said, “like this one!“ The manager then said, oh yes, we have them as loaners and you just have to purchase the test fluid. This was the first time I used a loaner tool. You essentially pay for the tool, and they give you a full refund when you return it.

The moral of the story: do not expect them to know what it is. You have to help them help you.

Good Luck

schil01-camper

The block test (combustion test) indicated that no exhaust is getting into the coolant. I repeated the test three times at full operating temperature.

I re-did the radiator leak down pressure test (cold) and it held >15 PSI for over 15 minutes again. I did these tests with the coolant level about 1 inch below the cap hole (for the block test and pressure test). yesterday the coolant was pretty much full when I did the idle pressure test and measured a very high 15 PSI (causing the head gasket panic). I believe that the liquid that got into the radiator cap adapter (it didn't get into the tool itself) and affected the readings. Reading other 'how to' guides on the web indicates that the coolant level should not be so high. Maybe I had an air bubble in the system or maybe it was the high coolant level, but yesterday the radiator pressure when running was >15 PSI and today it's only about 3 to 5 PSI (normal). So today's radiator pressure at idle is normal and there is no exhaust in the coolant - both indicating that the head gasket is not compromised. Obviously I will keep an eye on the system but for now I'm going to consider this head gasket issue to be resolved: It is Not my head gasket.

My coolant loss must have come from some other issue. I'm going to start by getting an OEM radiator cap as I'm not so confident in my current one. I de-greased and washed off the engine/trans today so that I can clearly see any new leaks or deposits. I'll take it out on shorter runs and see what happens.

Also, I followed your suggestion DalasTX about getting the tool. The person at Autozone had no clue about a block tester, but the call to O’Reilly’s was successful - the person there knew exactly what I wanted. I drove straight there and the loaner was a brand new item (never used). yes, you pay for the tool and then I'll get a refund (minus the test liquid cost) when I return it. The tester is very sensitive to CO2 levels. It can even detect the CO2 when I exhale and blow into the bottom of the tester when air is being pulled through it. It also gave a good "no reaction" (stays same blue color) -- meaning that I could pull regular air or my radiator gasses through it (over 50 pumps) and no color change. All of this makes me relatively confident in the readings. If there was any blow-by getting into the cooling system this test would have found it.

I am cautiously optimistic that I mis-diagnosed a failing head gasket. So for now I say: Whew, what a relief. However, if anyone reading this thinks I'm wrong please feel free to let me know.

Co_94_PU

iTrader: (-1)

I'll play devil's advocate. Coolant doesn't just disappear, it is a semi sealed system if it's not in the overflow/expansion-tank it went somewhere else.

Air in the system tends to force coolant out of less than perfect hose connections, or you'll notice junctions are damp if not dripping that sort of thing. If that air pocket is on a sensor you will have EFI issues also.

A good radiator cap is a good idea even if it's not the underlying issue. Some aftermarket ones don't seal properly which prevents the system from drawing coolant from the tank, they'll just sick back in air from around the cap. Also along the same problem line the pressure ratings are way off, when the pressure is to low the coolant vaporizes sooner the overflow heats up and looses its ability to recondense the vapor before it escapes out the vent, you'll see lots of steam and expulsion of fluid before 170*.

How about a UV dye kit to chase the coolant, I'm not sure if that stuff survives the heat cycle but I'd think it would show on the exhaust pipe maybe but it would for sure show if it's steaming out at the tank.

schil01-camper

I agree - the coolant had to go somewhere. I plan to search for the culprit systematically, but for now I'm demoting the head gasket to the "unlikely" category. I like your idea of the UV dye kit. If I can't find the problem and it continues I will look into that further. If I had a bunch of leaks, would this make my engine by look like a tie-dyed t-shirt with a black light? That would be a bonus.

On the last two trips (~2 or 3 hrs highway driving each way) there was coolant loss, but I wasn't paying close enough attention to when, where, or if there was a temp spike, etc. Now I plan to be vigilant and hopefully I'll be able to spot the problem more accurately. Fortunately this issue has not involved any obvious overheating or significant coolant loss so I think i'm ok to continue on with camping as usual as long as I'm keeping a close eye on things.

DallasTX

Good news on head gasket. Perhaps a dumb question, but any chance your overflow reservoir is leaking? Like CO 94 PU said, coolant has to go somewhere. The reservoir is not part of the pressure test, so just thinking that perhaps as the coolant heats up and overflows into the reservoir, maybe it leaks out of your reservoir as you are driving down the road.

schil01-camper

It is good news on the head gasket. I checked the reservoir carefully and it does not appear to be leaking. Now with everything cleaned up in the engine compartment I should be able to spot any leaks or overflows more efficiently.

The coolant has to be go somewhere. Now I have to find out where it's going. I plan to be doing some additional work on the engine in the coming weeks so I'll be able to keep an eye on it. I am going to replace plugs, adjust valves and pull the injectors to either clean or replace them. My overall goal is to get a little more out of the 22re to get me down the freeway a little more efficiently. In that process hopefully I'll solve this coolant question.

schil01-camper

I thought I'd give a brief update. After de-greasing I noticed a patch of tan powder dried onto the driver's side of the block, sort of between cylinder 1 and 2. It looks like it came from the head gasket and looks like dried coolant. I do not know if this is recent or has been there for a while. I'm guessing it's relatively recent and is where some of the coolant has been going, though in may be in parallel with pushing past the cap. Thus I'm back to the head gasket problem, BUT It doesn't seem to be a "critical" failure. In three 30 minute highway test runs I saw zero indication of any leak. Coolant stayed at exactly the same level and there was no discernible problem. No leak. My guess is that there was a stress/temp spike or RPM surge or whatever on the two previous 4 hour trips and the coolant leaked past the head gasket to the outside. Under 'normal' short operating conditions/temperatures it's ok and doesn't leak. Under load after a few hours and when pushed a bit hard it seems to leak. Seems unusual though doesn't it? Since it doesn't push a lot out I think I'm ok to continue on shorter trips and watch and learn more. I'd like to actually confirm that I can see it leaking and note the conditions before I jump on changing the head gasket (ugh). I think I can pay attention well enough to not get stranded (famous last words...?)

If the head gasket is compromised the it will eventually have to be replaced (or maybe I'll just get a 6-cylinder engine...). It is possible that I'm OK to drive it like this for a while if I watch it carefully (right?). If anyone has ever seen an external leak of coolant from a head-gasket like this that was "manageable" (seems unlikely) I'd be interested in hearing from you. If you think I'm a total pin-head for continuing to drive it like this I'd also be interested in hearing from you.

Meanwhile, I have been pursuing an attempt to coax a touch more power out of the 22re on this thread. Summary is that I have replaced the injectors, confirmed the timing, valves, new radiator cap, new plugs, cleaned the EGR, replaced a few hoses and PCV, plus confirmed no vacuum leaks. (and no coolant leaks in all this fiddling). With tuning done (it's running nicely), I'm now going to put headers and a bigger exhaust pipe on and see what happens. It's arguably foolish to pour money down some headers on a possibly failing head gasket, but I already bought the headers by the time I diagnosed the dried coolant on the side of the block so I might as well put 'em on. maybe I'll make the muffler REAL loud just to draw attention away from the coolant leak....

Co_94_PU

iTrader: (-1)

Good evening camper!

Thanks for the update.

Did we suggest the coolant uv dye tests previously? Seems a good investment now that it's all cleaned up that will stand out very well if it starts acting up again. You don't have to purchase the uv light just the dye, then when you feel it might be warranted stop by the local store and wave that magic wand around.

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schil01-camper

The UV dye would definitely be a useful thing to add to the coolant now that I have everything cleaned up. You mentioned that previously and now I think it's time to give that a try. Thanks for the suggestion, that's a new trick to me.

schil01-camper

THAR SHE BLOWS!!

Head gasket blown. Yup. I sent her to the local shop yesterday to have a header put on and she came back with a full-blown headgasket failure! (Ouch) Coolant is leaking out _exactly_ at the same point where I saw the dried coolant on the side of the block. It looks like the head is cracked at that spot (as in more cracked now). It's also right where a rather stuck exhaust manifold bolt/stud was... I don't have the tools to deal with super-stuck exhaust bolts, and this is why I sent it to the local shop. Anyway, whatever they did caused a total failure of the head or gasket. I don't blame them because they simply accelerated the result that was inevitable anyway. It's pretty clear now that my head gasket was compromised based on that dried coolant on the block. Maybe I could have limped along on it for a while, but likely I could have been stranded. Better to deal with it now in my driveway than 200 miles from home. Still sucks though.

At this junction one has to seriously consider a move to a V6 engine compared to simply fixing this 22RE. I will briefly outline the pros/cons for my particular project and invite any comments.

Option 1 (keep V4 22RE): Maybe 120 to 135 HP max for the existing 22RE with new engnbldr head and cam plus header/2.25" exhaust and add increased air intake (and tuned up perfect). This would help but ultimately leave me 'wanting more'. Cheaper, easier, fast to complete that would be functional/adequate (with zen like patience behind the wheel) but still ultimately lacking in power to move the Brick (camper).

Option 2 (swap to V6 5VZ-FE): Maybe 190 HP for a well running bone stock 3.4L V6 5VZ-FE. This would likely be adequate power to reach my goals with this driving brick of a camper. However, IMHO a huge PITA to accomplish.

I realize that one ought to 'do it right, once', thus: do the swap. However, it involves a lot of tedious mods (plus tools & learning): custom mod the wiring, engine mounts, AC, power steering pump connections, evap box, intake, etc. etc. This is just WAY beyond my available time and gumption. The upside is that if I did this I'd be all set with the camper in terms of having adequate power to get down the road for years to come. Too bad it's such a PITA to do the 22RE to 3.4 swap (at least compared to a 'simple' head gasket job).

Current Decision: Do the engnbldr head swap and get the existing 22RE running with the new exhaust for a total of ~$750 ($530 for head plus $220 to complete exhaust pipe). engnbldr suggested his 'stock' head (higher flow than OEM stock) with a 261 cam would be a good match for my header and 2.25" pipes. I think my bottom end is fine, and before the HG blowout it was tuned up great. Seems like a good investment to me but I'm open to other options on heads if anyone has some ideas. I think I can do the head swap in a day - 1.5 days if I get in there and find that I need to deal with the timing chain/guides. (at 87k am I really stupid to consider avoiding the timing chain if it looks ok?)

I will not eliminate the V6 swap option but I'm going to have to gather more research to understand what I'm in for (I don't even have a hoist and my transfer spot is on gravel, ya dig?). I did see a 'well running' 3.4 donor for $500 locally in CraigsList. That has to make a guy think hard about upgrading to a V6...

Co_94_PU

iTrader: (-1)

I don't think another 22re is the way to go, but it's not my project, given that you've been unsatisfied with the performance you are probably already leaning tongue v6. Sadly the 22re is just not up to the load of that brick shaped heavy camper on the back. That said, You could realistically get another 20-45-90k miles out of the head gasket fix but it's going fail again from all the heat most likely. search around yotatech and see when they tend to die I've never to my recollection seen one over 100-120k. Can you accept throwing away that kind of money, fixing the 22re only to replace it with the v6, you might not be able to recover?

Regarding the prices it's always best to over estimate, 1.5-2 times your initial part price gives a good margin of error for all the consumables and little things that pop up but you could go quite a ways over that if you're not diligent in planning and keep a close eye on the budget.

For example, I change my oil and coolant everytime I need to remove my turbocharger (to fully inspect it, to change fittings, ECT) at 50$ a pop and doesn't include the gaskets I shouldn't be reusing (but do because it's not to a final fit stage) that adds up quickly so much I have more invested in fluids than the turbo and wasn't planning far enough ahead.

That said the bottom line is plan ahead overestimate your expenses keep an eye on your budget and be able to go over it without going into debt. Anyone can do the head swap, it's time and money and following the manual. A v6 swap is similar but add in a lot of research more tools and some hair pulling to research and prepare.

Both will be a learning opportunity, neither will be uneventful, the 5vze in a Winny (?) Might be a first.

PS: Is it a Winnebago box, the Dolphin, or one I've not seen yet?

schil01-camper

I think you are right that I'll likely blow the 22re engine again given that I have to push it very hard just to keep up with traffic. A 5vze would give it a more useful and longer life. Clearly the better choice in the long run. If I had a donor truck and was not limited by time, tools, know-how then I'd go that route now. I'm going to keep looking into the specifics surrounding an engine swap so that I make a more informed decision before ordering a 22re head. I found a used 3.4 engine locally today but the guy just pulled the motor three days ago and the donor truck it came from is already gone (along with the air box, ECU, and many other parts that would be needed). No suitable donors in the local yards so far, no obvious ones on craig's list nearby.

I also hear you on the expenses. The cost isn't the limiting parameter to me, it's donor truck/engine, time, knowledge and tools. In my head I do add the 1.5-2X increase over parts because that's just the way things always work out. My overall hesitation with the 3.4L engine swap is not the extra cost but the time and attention required. It would be right on the edge of what I can dedicate to such a project. It would be better to have a 22re running soon than an unfinished engine swap project nagging me because I have to prioritize work over play. It would not bother me if I spent the time and money now to put a head on there and get it going only to turn around and do the 3.4 swap after a donor truck shows up (or the engine dies again). At least then I could plan and schedule it and still have a working camper. To me the head gasket job is something I can handle in a day or so (though I'm prepared to go longer if the chain guides are worn for example, but last I looked the original plastic ones were fine). I'll take a good look at the timing chain guides to see what shape they are in.

The camper itself is a "Sunrader" 21 foot. Fiberglass shell. The whole reason I'm zipped up about this '87 camper is because when I got it (free, a family hand-me-down) a couple of years and ~20k miles ago it needed a lot of camper work. I put in the effort to refurbish the back end. There are no leaks now, repaired/upgraded/maintained the fridge, gas heater, AC unit, generator, hot water heater, oven/stove, water lines, shower/toilet, interior water valves, new LED lights, new charging system/batteries, and more. It's totally NOT fancy or pretty to look at, but fully functional. Small enough to park in a regular parking space, big enough for 2 adults and 2 kids. I can even strap a canoe on the top. A good get-away vehicle. The only limitation is the 22re. You have to wrestle it down the road.

Co_94_PU

iTrader: (-1)

Dive in! Plan to do the front end you don't want to take it all apart again, the wear spec for the guides is under .5mm. talk with the machine shop again they have a great reputation up there, and can give you an all inclusive kit and guide your part selections.

schil01-camper

"Dive in! " I took your advice Co_94_PU. I will get the 22re going now, and then if the stars align later and I find a donor truck then I'll revisit the 3.4. I am not giving up on the 3.4. I do think that is the right goal to keep in mind in the long run. However, in the mean time I'm going to get this thing going with the existing 22re. It's already warm enough here in Atlanta to be out and about in the camper....

I tore it down today just enough to determine all of the parts I'd need. I got the radiator out (mine is weird with an extra 'loop' through it carrying transmission fluid through the radiator and then to another trans cooler in front of the radiator), all the accessories and belts are off and 'bumped' the crank bolt off with the starter using the cheater bar trick. I got the exhaust and intake manifolds off and then surveyed everything and then ordered parts. It will take 5 to 7 days to get all the parts so I didn't want to take the head and the timing cover off just yet. I'll have those off and cleaned up and ready to do the install when the parts arrive. Everything looks good for finishing the head and chain in a day or so after parts arrive. The 22re is a pretty easy engine to work on and although there are a lot of steps/details, the head and front end work is pretty straight forward stuff.

I ordered the necessary supplies from engnbldr. You know, he will just talk on the phone for a good while if you let him - very amusing fellow. I grew up in Portland where he is located so we chatted about all the changes there in the last 20 years since I left. I feel good about getting 'the good stuff' from him and the engine will be happier too. I looked around and there are so many 'questionable heads' out there for sale -- they all feel like there is a risk of a problem, but engnbldr has a 100% positive rating and he is creating a custom product that is extremely well regarded by this community. It does cost a bit more than the standard ebay stuff, but it's really not that much more, and if the quality is like everyone says, it's really worth the extra $ for top shelf parts. So after talking about my situation with engnbldr, he said his 'stock' head and a 261C (crawler) cam is best for me. I tried to talk him into an upgrade on the head, but he said that with basically a stock 22re plus the hedman shorty header and 2.25" pipes, his "stock" head (which is still an upgrade from OEM with the new custom casting) is the right way to go. I have to defer to him on this issue.

I also did as Co_94_PU suggested and bought the whole front end kit. Might as well do it right while I'm in there.... The chain and guides look fine with "wee bit" of wear, but they are the original plastic ones so I'll just get all of that refreshed while I do the head. New cover, water and oil pumps too. It's overkill in my case because I'm less than 100k miles, but it's not that much extra $ now that I'm in there. I'll have a clean intake, rebuilt injectors, good tuning, clean egr, new plugs, clean wires and distro, new cam and upgraded head and a header and 2.25" pipes to push it all out. I should have a good sturdy stock-plus 22re after this.

I'm glad I got a start on it today because I think I have all the parts ordered now. I had to track down decent manifold stud bolts and nuts and a new gasket for my header. The worst issue was a bad idler tensioning pulley for the A/C compressor. It's aftermarket AC so there is no "part" available. I had to press the bearing out of the pulley and found that bearing for $7. It was toast. It had been chirping for the last 5K miles so I'm glad to be able to fix that too.

Co_94_PU

iTrader: (-1)

The smaller unit in front of the radiator should be your air conditioners condenser, please confirm this by tracing the lines. AC compressor is located at the bottom right hand side of the engine ( on your left when facing intomthe engine bay ), it has insulated hoses if that helps, they will also connect with a vertical cylinder located to the left ( your right ).

I am surprised they didn't upgrade to a separate transmission cooler when they received the chassis at the Sunrader factory. Upgrading to a separate and larger transmission cooler will make a marked difference. Maybe more so than your plan to put on headers.

Going from the standard 1.75 exhaust to the 2.25 doesn't seem that much untill you do the area calculation. From about 9" to 16" is a big jump and allows a ton more flow and ability to remove heat.

schil01-camper

I didn't explain the cooling routes well. Thankfully, the transmission does have a separate heat exchanging radiator that is in front of the engine/coolant radiator, but the strange thing is that the transmission fluid goes through the regular coolant radiator First before it travels to the separate transmission fluid radiator (why?). This is in addition to the AC heat exchanger/radiator. In total there is heat exchange for the coolant, AC freon, transmission fluid and even a little loop to cool the power steering fluid (four separate fluid heat exchanging systems). Surprisingly, all of this is in very good shape.

I agree that the transmission fluid cooling is a good thing in this camper. It's probably the reason that the auto trans has been zero problem while I've had it. I should probably give the trans some attention - at least determine if fluid change is needed (it has has _zero_ leaks).

On the exhaust: At this moment I only have the header sort of rigged into the stock pipes with the cat hollowed out. After the head is in I will take it to the local exhaust shop and determine (guess) at the right combination of collector, resonator, muffler and pipe diameters to get the right balance between power, flow and noise (I'm going 'no cat'). Interestingly, after the header install with just the header (no pipe) I could really tell that the lack of back pressure was hurting the engine after ~2000 rpm. It needs the right amount of back pressure to make it work right. Hopefully I'll land on a decent configuration after the new head is in. Totally open is no good. Restricted at 1.75" is also no good. Somewhere in between is the right amount of flow/restriction. I've had several people tell me that all 2.25" pipe is too much for my non-souped up engine. Something to consider. I'll work with the local pro at the exhaust shop to come to some sort of reasonable middle ground.

Co_94_PU

iTrader: (-1)

OK, that is much clearer.

The OEM cooler is the loop in the radiator, the add-on precools it before entering the radiator. This utilizes the extra cooling of the fluid to fluid system and will put less heat into the engine. There is another benefit here because the transmission doesn't like it if the fluid is excessively cooled and running it through the engine coolant provides for a stable and controlled temperature. For example winter driving without the radiator loop could excessively cool the transmission fluid stressing the pump and other components.

The risk is what's known as "strawberry milkshake", the transmission loop is prone to corrosion from the coolant side. There is no way to evaluate this damage easily, you have to remove the tank from the bottom of the radiator to get eyes on it.

The best bang for your buck transmission wise in my opinion is the larger radiator used on the 22rte, however it is very difficult to locate, it is about two inches longer on the bottom which adds a lot of surface area, and it's three rows vs two row so more efficient.

You may already have it actually.

Either way a new radiator or refurbishment will (well should, quality control seems to be going downhill but I digress) give piece of mind over cooling concerns and mixing of fluids..
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. Exhaust there is a big and popular misconception there, scavenging is good, back pressure is bad.

Scavenging is the exhaust pulse of one cylinder pulling the next exhaust pulse along with it, this removes more non combustible material from the second cylinder. We don't have very big of a combustion chamber but on much larger engines it can make a marked effect.

Back pressure is an impedance to flow, and only good for a turbocharger only if it is between the exhaust valve and turbine, and even then can be excessive. It (back pressure) robs performance (more non combustibles left in the chamber) and decreases the ability of the exhaust system to remove heat from the engine (less and slower flow).

The down side to an over sized exhaust is only due to the increased surface area along the pipe which can cause turbulence and negatively effect the scavenging, not the lack of back pressure.

A tuned exhaust is not a bad thing however we're very limited in choices, we can not really alter the length of the system and are limited in pipe diameter to off the shelf sizes. If we were race cars we could tune the length and use a custom diameter pipe.

I think what you experienced was a mild change if any and the "butt dyno" is giving you a false reading based on what you expect due to the exhaust note of running the more open exhaust. "It's so loud you expect more from it and it seems inadequate"


Keep the pipe diameter from header the same all the way back to the tail, use a free flow cat and resonator, and insure theses are quality units which won't pinch down internally to anything less than the inlet. (Non quality units I'll have smaller oriffices internally at some point, you should be able to see thru good one an notice it's the same all the way to the outlet)

I probably rambled longer than attention spans so I'll get off my soap box..