head gasket in 4 runner

OBX Fisherman

OBX Fisherman

Well-Known Member
Joined
Mar 21, 2005
Location
Winston-Salem
The head gasket in my 91 4 runner blew this morning on the way to work. It's the 3.0 v6 that has a history of blowing head gaskets.

Do you think it's worth while to pull the engine compleatly from the vehicle to change the head gaskets and also replace the main seals? It's been leaking oil terribly from the RMS, might as well fix as much as I can.

Thanks
 
I dunno about anyone else, but I haven't seen too many rear mains on Toyotas leaking.

The usual culprit is a valve cover gasket or oil pump seals the leak enough oil to blow back to the trans cover and dripp there.

3.0 valve cover gaskets are notorious leakers, as are the oil pump seal O-rings ( between pump and block behind timing belt cog) the seal gets hard and brittle with age and eventually lets pressure by.

Not saying the rear main is NOT leaking, just a few ideas to check.
 
I just overhauled a 88 3.0 and given the design, I would not expect the rear main to be leaking. As noted, its usually the valve cover gasket. The engine is a MF to work on. Its been my experience with replacing head gaskets that the rings become less effective when a fresh set of heads are installed. Oil consumption will go up but it will likely NOT smoke. Buy a set of head bolts from Engine Builder out of Washington State. He is a mechanical engineer and has his own line of parts and he is good at what he does. The cross over rear exhaust and the intake will frustrate you to no end. Soak bolts the day before removing them. Use lots of antisieze during reassembly.
Best of luck. If you got a hoist, you may want to pull it because working on it on an engine stand will be a blessing. Contact Toyota, they may take you in on their recall and give you a new motor.
LOL
:beer: :popcorn:
 
I would at the least have the heads pressure tested and surfaced. And as noted, new head bolts too.
 
Here is some tips. Unbolt the upper intake and flip it over to the passenger side without unhooking the vaccume lines on the passenger side. That way you do not have to fight with hooking them back up in the right place. Unbolt the down pipe and leave the crossover pipe and manifolds hooked up to the heads. Pull the head bolts and lift both heads, manifolds, and crossover off all as one. Then all you need to do is unbolt the manifolds from the heads and don't have to worry about the crossover studs breaking or leaking.
 
Thanks for all the tips! I'm procrastinating on this project right now. I need ot get some heat in my garage so I'll be more motivated to work on it!

Thanks

Gary
 
BTW ALWAYS and I mean ALWAYS replace the knock sensor harness under the lower intake manifold when doing a headgasket job.
 
bah

I've done many head gasket jobs on those bastard engines. Make sure yours doesnt have a recall on the head gaskets, as many 4-runners do, its called a v06 recall, and usually you get a new short block and valve job due to coolant corrosion. and its at no price to you. I have also seen many high mileage rms leaks, but most of the time it is the oil pan. good luck, and get a knock sensor harness!:beer:
 
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