Ohio4Runner

Good afternoon, Yodas of the 'Yotas!

This is my first post to announce my intent to take on the BHG replacement in my 1995 4Runner.

I bought it used recently and soon after it started overheating after about 15 minutes of driving. No big deal, as winter necessitated the heat running anyway.

That's not going to cut it anymore, though, with summer approaching. So, it's time to fix!

Diagnosis:
1. Overheating.
2. With radiator cap off, starting the engine jets a bunch of coolant out the opening.
3. Over a certain fill level, leaks develop around hose clamps, the radiator drain, and somewhere at the back of the engine. Below a certain level, those leaks stop.
4. Closely related, during operation, the upper radiator hose is rock hard - CONCLUSION: something is pressurizing the coolant system.
5. Radiator, cap, and water pump new, system completely flushed recently, and no difference.
6. SMALL amount of chocolate milk under the oil cap about 1000 miles after most recent oil change.
7. No discernable amount of coolant in the crankcase, or oil in the coolant.
8. No rough idle or white smoke.
9. Truck runs great, gets good (hahaha) mileage.

So, it seems that exhaust gases are leaking into the coolant, raising the system pressure and heating up the coolant.

Since my prayers for an easy fix were answered with "Time to build some character, son!" I know how my next several weekends will be occupied.

I will try to provide copious pictures as I go. (And will update my profile a bit too - only so much goofing of at work at once!)

Have a great day, and wish me good luck!

Ohio4Runner

OK, I started the teardown this weekend. I removed the radiator, power steering pump, fan and clutch, alternator, air cleaner, and belts.

I spent most of today labeling and disconnecting fuel, coolant. and vacuum hoses. Putting this back together is gonna be a bear!

I have several pictures to load but can't get them to the right size. Any tips are appreciated.

Some interesting findings so far:
- 5 spark plugs were the same, and one was a totally different type. Why in the world would someone have done that?
- Lots of rust in the coolant. I flushed it a few weeks ago but did not remove the thermostat to do so. It looks like quite a bit of rust was built up behind the thermostat.
- Speaking of, the thermostat seems to be the wrong kind - no jiggle valve. If it still works, I am going to drill it out and reuse it.
- Spark plugs have white residue on the contacts, and the insulators have a reddish tint. Any idea what that indicates? Only one seems to have a very small amount of oil on it.

So far it's pretty straightforward, just time consuming to disconnect everything. Putting it back together...well, let's think happy thoughts for the time being!

Badger62811

You have no idea....

Take lots of pictures. Keep track of where all your nuts and bolts came from. I have a few that didn't go straight back into their places that are sitting on the shelf right now. I constantly look at them and ask myself "Where the hell did these come from?"

I'm currently in the process of replacing my HG in my 22re. My only symptom was exhaust in the coolant. At first, the only time I knew something was wrong was when I would turn off the engine and coolant would explode from the radiator cap. Otherwise I could drive the truck forever as long as I didn't turn it off. It eventually got worse and lost coolant out the cap the whole time the engine was running.

Best of luck to you and your vacuum hose adventures.

annoyingrob

Let's hope that running with it so long hasn't pitted the head or block beyond repair too.


Good luck, you'll feel a lot better when you complete it. Don't cut corners, and take your time

MID SIZED BOSS

LOL!

I love my Yota but this is just embarrassing! I too have an internal head gasket leak. I too have exhaust entering the coolant galleys. I too have a thread following my rebuild.

Looks like we are in the same boat hopefully we both come out on top

As far as getting your pics to be proper size tell me first how you are currently posting them onto your thread. I upload my pics onto my PhotoBucket.com account and insert the links from there using the "Insert Image" tab.

Badger62811

I never got the white smoke or the mixing of fluids (Thankfully)

If I didn't love my Yota so much I'd get me a 5 gallon gas can and a match...

MID SIZED BOSS

I could never not love my rig...even if it seems to hate me.

I didnt mixing either but I did get a small amount of white smoke, thinking that was just steam cleaning from coolant going into the cylinder lol.

Badger62811

I (think) I got water in the exhaust, too. But at -5 degrees it's hard to say if it's condensation pouring out the tail pipe or if it's coolant. Exhaust smelled a little sweeter, too. Not that I was sniffing it... Same with the exhaust. Hard to say if it was a little white "smoke" or the usual exhaust.. I dunno. Doesn't really matter now. It's all torn apart now.

The bubbles in the rad were a definite sign of foul weather...

Ohio4Runner

"Let's hope that running with it so long hasn't pitted the head or block beyond repair too."

I hear that. I've put less than 300 miles on it since I realized what was wrong, and that only 3-5 miles at a time, so I'm hoping for the best.

Finishing my coffee, bacon, and eggs, and it's back out into the garage for Round 3!

MID SIZED BOSS

sounds identical to my issue. it will be interesting to see how all three of our rebuilds go (fingers crossed)

Badger62811

mmmmmm.... Bacon....

Ohio4Runner

I boil-tested the thermostat today. Opened weakly at 180, fully at about 195-200. Curioser and curioser. Some shoddy parts and lazy mechanics in this vehicle's past, it seems.

Ohio4Runner

Slower day than I thought. Got the fuel injectors out and the engine wire harness off (that's gonna be fun to put back too). Got the timing belt off too.

Got stuck on the exhaust manifold and the crossover pipe. I sprayed them down with penetrant, hoping that tomorrow will be a better day.

I tried making a tool to get the camshaft sprockets off, but they just bent the studs on the tool. Back to the drawing board!

I had a coolant leak at the back of the engine, and I think I found it. One of the hoses on the water inlet at the back of the intake was missing a clamp on one of its ends. I'm thinking that when the exhaust pressurizes the coolant, it is forcing it out of this section. It seems to be right around where the worst leak was, and the threads of a nearby piece have some greenish residue. Maybe the culprit? Let's hope, it's an easy fix!

Next up: exhaust, camshaft sprockets, and intake. Then we're in the real deal!

annoyingrob

Yeah, when the cylinders are pressurizing the cooliant system, ANY weak joint is going to leak.

For teh cam sprockets, I usually stick a big screwdriver through one of the holes to jam it in place, and loosen it with a big breaker bar.

Ohio4Runner

Heads are off. Lots of carbon deposits, but no cracking or warping that I can see. Just really dirty. Is that enough to cause contamination between the cylinders and the cooling system? It seems like it would, right?

Pictures to follow this weekend. Right now it's off to the store for some supplies!

Ohio4Runner

OK, time to pick up where I left off. Two of the operations at the company I work for were hit by natural disasters right after I took the heads off...two months gone.

So, the heads are back on, and I have been road testing for a couple days now. Assembly went fine, with no real hold ups other than the usual minor annoyances.

As you can see from the attachments, there was pitting on the heads as well as significant sludge blocking the coolant passages.

The surface of the block looked bad when I removed the heads, but that turned out to be carbon build up. It cleaned off fairly easily. I could find no major warping, but there were a couple of ridges in the metal that I removed, and a couple low spots I filled in with JB Weld. They were small, and tended to be right around the edges of the old gaskets.

The cooling passages in the block were nasty with residue, since some time ago it appears that green coolant was put in and left to sit. I cleaned the passages with steel brushes from my gun cleaning kit, and then hosed them out until the water ran clear from all ports. It took awhile, those passages were pretty corroded, as you can see from the view into the thermostat housing.

Ohio4Runner

I have never taken an engine apart before, and this was an interesting exercise. For one thing, I get the sense that someone else had been in there before. Not sure why, but maybe because there were a few small scratches on the block, for example. I know at one point at least the intake had been off - you can see in the attached picture that the hose clamp on the water bypass outlet is off. This was the source of an "invisible leak" I had earlier coming down the back of the engine. It would drip onto the crossover pipe or down on to the transmission. Some in-a-hurry mechanic didn't put it back together properly, and once the exhaust gas started pressurizing the cooling system, it pushed it right out.

Tip - always put the hose clamps back on!

It was also interesting to note how you can NEVER take enough pictures. You think you are taking too many, but you are not. Take more. Often I'd say to myself, "No biggie. Of course I'll remember where THAT bolt goes. Look how it's shaped!" Then, six weeks later, I'd curse a blue streak at my six-months-earlier self: "Why did you so this to me you $%%*$$?! You could have taken one more picture!"

Tip - always take one more picture.

One line that ran through my head the whole time: there is a story in the Bible about two kings getting ready for war, and they are taunting each other. One of them says "The man who puts on his armor should not boast like he who takes it off." Revised for Yotatech: "The man who takes apart his engine should not boast like he who puts it back together."

Tip - be vigilant and confident, but not cocky. There is much that can go wrong.

Ohio4Runner

So, the road test:

I have been dreading the road test for a few weeks now. One leak, one bad seal, one off-center gasket, one hose clamp not put back...so many things to go wrong. What if?

Once back together, I turned they key, and it started right up. WOW! But then...smoke. A lot. Something was burning. So I shut off the engine and grabbed the fire extinguisher that I should have had in the garage all along anyway to wait it out.

It turned out that the exhaust manifolds had some oil/residue, plus I used copper thermagasket on them, and the excess had to burn off. Then I noticed a coolant leak. Shoot! Turns out that was, you guessed it, a hose clamp I didn't tighten down. 1/4 turn with the screwdriver, and leak averted.

It took a few more minutes to burn off the residue on the manifolds, but it did abate, so it was time to drive.

After a short tour around the neighborhood, just like before, the temp started climbing, fast. The feeling of despair was great. So, moping, I came inside and paged through these here forums and read up on burping. So, I put the truck up on ramps, topped off the radiator, and ran it for about 25-30 minutes, regularly squeezing the upper and lower radiator hoses and bouncing on the bumpers. I think part of the problem too was that I did not run the heater earlier as I was putting the coolant in.

So it was time for another road test. 30 miles later, temperature was perfectly normal, on an 80+ degree evening, high humidity, and A/C running. Before, highway driving of any kind made the temp rise. Now, it stays steady on the highway, just like it should.

Today, in the middle of the day, I took it on another road test. 90 degrees, high humidity, family on board, high A/C. On the highway, it performed wonderfully. The temp started to climb going up a large hill, but came right down at the top. However, it was climbing during the around town portions of the drive. In all, I drove about 70 miles. It never overheated, but did get hot. No coolant bubbling or anything like that, but the gauge went to about 3/4.

I wonder if a combination of factors are at play here:
- ignition timing was done by guesstimate. I need to get that set properly.
- 90+ degrees, high load, low speeds. Maybe it just runs hot?
- Needs a better thermostat? I bought the cheapo, since I am going to change out the coolant in 500 miles anyway. I also drilled the hole at the bottom to improve the coolant flow.
- I wonder if the A/C fan is functioning properly? Does anyone know how to check this? When I bought the vehicle, the A/C was disconnected and hadn't been operational in two years. I need to road test without A/C and find out if that makes any difference.
- Perhaps 3/4 of the gauge is nothing to worry about? I am still somewhat reticent from the previous overheating issues, so maybe it's really no big deal.

The fact is, this is a second car. Today I drove it harder than I would under any foreseeable normal circumstances, and I live next to Lake Erie. Cold weather performance will be the more likely scenario. If I end up in year-round 90+ weather, then maybe it will be a big deal.

So, on the whole, a smashing success so far in the road test!

Ohio4Runner

Not all is boasting, though.

The power steering pump has a small leak that will need fixin' eventually. Also, a few of the hoses will need to be changed out in time. They are starting to get a bit stiff. One paycheck at a time.

While I was in the left head, one of the camshaft bearing bolts didn't tighten as much as I would have liked. This is the part of the engine that has been chattering quite a bit in recent months. I foresee a new left cylinder head, but hopefully that can wait until next year. I put it back together as-is, hoping I can get some more time out of it before it goes really bad.

One of the finer moments is getting the A/C to work again. When I bought it, the previous owners said that the mechanic told them that "there was pressure in the system" that blew the discharge line off the compressor, and that it would cost a lot of money to find the blockage.

As I disassembled the engine, this began to smell like BS to me. I looked at the compressor, and the hold down bolt was broken. Maybe I am too much of a noob, but how could there be enough pressure to break a bolt off at the head?

I removed the compressor and took it to a mechanic friend, who extracted the bolt for $20. A new bolt was $1. The A/C works like new now. This is great news for me, but it also shows that not all mechanics are good ones - they flat out lied to the previous owners, and then tried to charge them hundreds of dollars to "detect" the blockage, when all it was was some jerk who broke a bolt, and was either too lazy or too dishonest to come clean. I have always told people that I like to fix my own equipment not just because it is usually cheaper and fun, but no one cares as much about my gear as I do, and no on else has as much invested in it as I do.

Ohio4Runner

So, now it is on to getting that last little bit of heating up figured out. Once I do, I'll share with the group so maybe someone else can benefit.

Thanks everyone in the forums for your posts, my education has been thorough, and this is about the coolest thing I've done in ages.