headgasket

Hello Yotaheads:

We have the 1994 SR5 5 speed with the Rock Gasket Set and Ted at engnbldr.com 's 10.9 Topline headbolts. Followed all tips from this forum.
Torqued to specs, milled heads flat, adjusted valves. Replaced radiator, flushed coolant, new timing belt, spark plugs, timed to 10 degress btdc, set idle to 850 after warm.

Coolant is topped to the exact spot 50-50 New Prestone Green Extended Life and now have 800 miles after top end rebuild.

From what we have learned, some on here prefer the Toyota OEM replacement gasket. The old Rock ones failed at #'s 1 and 6. No coolant that we could tell in the bottom end and so just got it up and running again.

My daughter has it back in Bend and has been told to watch for any drop in the coolant and to keep an eye on the temp guage. It is running just the left of middle, right where it's supposed to be.

Questions: What should we do other than keep oil in it and drive it? After all, its a used Toyota with 183,000.

If the coolant doesn't drop does that mean that it might be "good to go?"
How many miles does it take to figure out that the repair is working? Very curious. Some are adament that I should have gone with the Toyota gaskets over Rock.

Please advise. Thanks in advance.

TNRabbit

Did you replace the rings or do a valve job? Or was it just valve adjustment & heads milled? Did you check the block for flatness? Do you know the reason for the HG blow the first time around? Overheated?

Take it easy for another 1000 miles then I'd say you're in the clear.

toytech76

Did you pressure test the heads? We find alot of heads have porosity. I definately would have used the toyota head gaskets and done a valve job when I had the heads off. Now also remember, there will be some coolant level rise and fall. Now if the overflow bottle is empty, then you have a problem. Just watch the temp, coolant level and you can even smell the exhaust for a sweet smell to tell if you have any coolant burning

headgasket

Thanks TNRabbit and ToyTech 76 for your feedback. It's easy to get a bit nervous and overthink my careful work.

Answers to your questions so you can better advise me on break in and things to watch for.

I did not do a valve job at the time. That would have been more intelligent. For an additional $125 I could have had that done. Now the reason I chose not to was to limit my losses at this time. The valve shim I took seriously and made sure all were within the spec limits as per the FSM. I moved the shims around until I got it right. fun to learn how to do that. I do not have the tool so I have to take the cams in and out carefully.

The head was pressure tested the previous time and surfaced at that time as well. Not sure how many thousandths were shaved the last time at 152,000 miles.

This time at 182,000 the heads were polished so smoothe that I had a mirror finish, awesome. He said they weere .004 out so he took off .006. They looked primo. Just a top end to keep it on the road. You guys are great! Thanks for helping me make sure the job will work out. One last thing, what is the major difference in the Toyota gasket that differs from Rock? I would certainly like to see the 2 different gaskets side by side. Just my 2 cents.

headgasket

We have been watching, the coolant in the rad is full to the top. the overflow tank is filled exactly to the mark. I have monitored this closely and the temperature guage. No codes on check light other than EGR. It comes and goes code 71.

900 or so miles and looks good so far. Fingers crossed and then double crossed.

Thanks.

headgasket

Yes;

Overheat seems to be the culprit. Just cleaned the block meticuously with a gasket scraper, then razor blade, then brake cleaner. Will get a decent precision straight edge. On the list. If the block ever comes out then we'll do a complete rebuild or part it out. We owe about $3000 on it and it seems that's about the resale value. SR5 leather, 5 speed, new clutch, timing belt, radiator, runs great!

Paulsky

I put a light source behind my straight edge and pulled out my feeler guage at any low spot.

headgasket

Ok guys:

We're at 1000 miles plus and all looks good. Turning our attnetion to a free flow cat. Monitoring the coolant and temp. guage on dash.

Any advice on what to do or not do at this point to "insure that it doens't BLOW again?"

toytech76

It's a 3.0. It will blow again. You just don't know when. Change your coolant every year, make sure all cooling system components are functioning properly. Keeping up with your maint and taking care of the truck will help

headgasket

Thanks Toy Tech:

I noticed the second time in there looking down on the pistons that the whole process was a lot faster, easier, and that I'm beginning to understand how important not overheating that 3.0 with the crossover exhaust all pointing to #6 cylinder is.

It is a good solid Toyota engine. Great beginning vehicle for my oldest daughter. Currently with the tune up it is getting 18 mph crusising up and down I-5 to Portland and back at hiway speeds of 67-70 mph.
Not bad in my book for a rig with 183000 and the heavy body that it is carrying.

toytech76

not bad for a 3.0 thats for sure. It's not because of the crossover exhaust that made it blow. Its just the design of the block and gaskets. They usually blow on cyls 1 & 6 which are the same. You could swap both heads on either side and all the passages would line up, but you don't wanna do that. Just saying they are the same and thats why cyls 1 and 6 blow

tyrell2004

Here are pix of my old gaskets and new toyota gaskets side by side iIdo not know what manufature made the old ones as they were put on by a bad mechainc who sold me a crappy rebuild two years ago. I am about to put new heads on mine after they blew. Looks like he put used un prepped and machined heads on my truck, the Rat bastard.
I am looking for a good source for reman or new heads right now.

tyrell2004

Looks like some of the holes are smaller around the problem areas

headgasket

Toy tech:

Good point there about the 1 and 6. I actually goofed the last time and ran the heads reversed. When it went into the shop for milling the heads and steam cleaning the machinist pulled the lower idle pulley. I knew less then about the heads being predrilled out on the passenger side front of the head to accept the washer which goes behind the idler pulley.

Anyway, to get out of that predicament since the heads were bolted on, valcovers, intake, plenium, etc. I took out my Harbor Freight grinder and was able to not unbolt the mess. I cut an arc in the head to allow for the idler to fit parallel to the head. It was in the middle of the night as I recall.

In any event this last time both 1 & 6 were blown. If it's not the crossover and build up of exhast temps there (at #6)as the primary underlying cause as some portend then I can see why that's not logical or if so why would cylinder 1 blow? It is a long way from #6 and the heat intersection.

Is it something iherently wrong with the head design around #1 and 6?

Why do some folks get 100,000-150,000 and others get to repeat.

Why as some say is keeping an eye on the temp. guage is not enough.

Why no warning.

Why do some work fine and others not. Confused? sort of like a game of Russian roulette wouln't one say. Point and shoot! Click. etc.

headgasket

I just compared your "Toyota" Brand Gasket with the blown Rock Gaskets I am saving. I could not see any physical difference from the digital photos.There seems to ba lot of hype about Toyota's (manufactured by an idependent supplier) and put in the red & white box vs. let's say the Rock Products Gasket. I am very curious if there are any REAL advantages.
From the photos, I see no difference to the Rocks in my garage.

Not sure of the blown comparison gaskets brand you have posted side by side.

I'm sort of leaning w/ engnmbldr. (Ted) that the gasket itself is not the problem. Rather the design of the engine itself, or improper installation i.e. clogged block headbolt holes, false torque readings, reuse of stretched TTY bolts.

I'll know a lot more as the miles pile up on our 94 4Runner. Hands on Experience is still the best way to learn.

SEAIRESCUE

Think about this thesis:
Why did the engine overheat and trash the head gaskets? Eliminating poor maintenance, goober driving, towing a 5,000 lb trailer, etc., my presumption is that the main clutch fan starts deteriorating with age. Its a gradual failure and not readily noticable from day to day. Eventually it will quit performing adequatey and allow engine temperatures to rise and really spike during the summmer. I say this because I have seen over the years lots of posts about the temperature gage starting to inch towards the hot side on older 3.0's. Consequently, one good strain on the engine when its warm and the internal temps around #6 start running up to high levels but not enough to truely overheat the cooling system. That is where many headgaskets start their long road to failure. So, I firmly believe that after a head gasket failure repair, replace that clutch or buy yourself a flex fan. And, ditto to what Ted believes in the causes of gasket failures the second time.

My $0.02

headgasket

SeaAirRescue:

That idea about the fan is worth looking into. I have a list of parts I have been having CarrieC price for me from Northridge Toyota. Great folks with the free shipping and 25% off retail that Evan Nichols set up for us yotatech forum users.

I'd be curious about the cost to replace that part. I'm glad there's 2 foot of snow on the ground in Bend, Oregon so we'll have a little time on our side to save up for the fan replacement.

I'd say your 2cents is worth a lot more than to me. Let's see here:

$144 to engnbldr. (Top end gasket set+ 10.9 bolts+ UPS to my garage.
$26 to Dave at the CarQuest Machine Shop (steam clean heads)
$66 " " " to mill the heads .006 inch (outstanding mirror finish)

Minimum I can get back in there for= that.

Of course there is now a new radiator, timing belt, thermostat, coolant flush, rad cap. But those I would not factor in as they are routine maintenace, just easier to do while in there. Water pump replaced the last time so it only has 30,000 miles on it.

Our heads have been shaved twice, so if they warp out of tolerance I'm in the market for new remanufactured heads or off to the salvage yards to get another set of heads.
Think I can learn how to use a valve spring compressor here pretty shortly.

Enjoying all of this, thanks for the tips.