Qbert

I am getting ready to pull my heads off again and I have had a friend tell me that putting the Permatex copper spray on the block side before the the new gaskets go on is a good idea. My question is to anyone; is this a good idea? and does it add any value to the gaskets?

still007

Just do it I did my head gasket without it just to find that exhaust is getting into the cooling system causing overheating. I had to re do the head gasket since i did not spray copper permatex on the block. it is only five bucks and prevents a headache.

scope103

I've done it both ways; I can't tell the difference. So as still007 says, it probably won't hurt, and it only costs ($8.50 http://www.autozone.com/autozone/acc...er=520940_0_0_) a can.

Qbert

So you are saying you already sprayed the copper permatex on your engine? if so how many miles have you logged since redoing the gaskets?

The kicker is my head gaskets are fine but I have to pull the heads off again since my machinist screwed up the valve clearances and I have 2 exhaust manifold studs pulling out of the heads.

Qbert

I work in a lab full of metallurgist and chemist and the mechanical minded ones suggest it to be a good idea because it would be a barrier between the dissimilar metals. I'm just wondering if it has ill effects doing it the my engine.

millball

I disagree with those who advocate the use of Copperkote or any other sealants on these headgaskets.
The iron block and the aluminum head have widely different coefficients of expansion, and in order for a headgasket to continue to seal after hundreds and thousands of heat and cool cycles, there must be controlled slippage at the head/gasket/block interface.
In order to facilitate this controlled slippage, most gaskets made for these engines have a slick graphite composition, and the headbolts are 'torque to yield', which gives an elastic clamping force.
The best results will be got by carefully degreasing the block deck and the head face with acetone, and installing the gasket dry and bare, without using any kind of sealants.

Sometimes iron head to iron block apps might benefit from headgasket doping, but I'm not sure about even that.

I don't know enough about the use of multi-layer steel gaskets (MLS) on these engines to make any comment, except to say that it seems that most users of MLS gaskets also resort to the use of aftermarket head studs.

I'd like to hear the experiences, either good or bad, of any here on the forum who have used MLS gaskets on the 3vze.

Qbert

Millball, now that is the kind of answer I was looking for. You explained it very well. I should of told people first that this isn't my first rodeo replacing head gaskets on this motor. This will be my 3rd time doing so and I have never used the stuff before but was wondering if it would benefit me if I use it this time.
The first time I did it was because it was just old and a lot of miles on it, the 2nd time was a water leak that I STUPIDLY used radiator stop leak and killed my engine. The head gasket from the 1st time I replaced it til I killed it was about 125K on it, so I guess the clean dry method was good enough.
Thanks for you intelligent quick response Millball

millball

Keeping fresh 50/50 coolant in your engine is the best defense against electrolytic/ galvanic corrosion.

After a few years service, the anti-rust/anti-corrosion package in the coolant is depleted and the coolants' PH changes, and corrosion rates skyrocket.
The coolant should be changed out for new every three years or so, even if it appears clean and clear.

My '87 had green in it when it came to me, so I've kept using it and the cooling system appears clean and uncorroded.

My '95 has never had anything but Toyota red, so I've stuck with red in it.

I do'nt know if it really matters as long as different types are'nt mixed.

Qbert

Yeah,
I used 100 strength coolant and mixed it wit De-ionized water hopefully to reduce corrosion issues that happen within the engine. I love my 92 4runner but it has about 350k miles on it's chassis. Never been stuck in it so far and that is going 30 miles down the national sea shore a few times. I would like to keep it another 10 years so when I rebuilt the engine a few weeks ago I am trying to do all the correct right things to it.

still007

I used the copper sealant for 9k so far and that was in severe conditions of two miles of washboard dirt road and up and down a desert mountain with no highway driving every day.