Solving The Valve Cover Gaskets - Permanently

[Toysrme]

I'm not saying this is how to do it (Tho, This is what I've done & it's been no-leak for quite awhile.).
(For the remainder of the thread VCG - Valve Cover Gasket. RVCG - Specifying the REAR Valve Cover Gasket, FVCG - self explanatory.)
It's obvious Toyota's implementation for the v6's does not work. Blame whatever you want, but there is no arguing the fact that it simply does not work. Worse, nearly every engine has a VCG leaking to some extinct, almost EVERY engine will have the RVCG leaking over time.

IMO it's from a culmination of two things:
1) I don't like the groove style VCG. The flat engine's use corker, rubber"ish", or rubber/steel core gaskets & have less problems. Not only that, but it is advantageous in that if it is ever replaced (for any reason) you simply use a tube of gasket maker & the seal is nearly indefinite. When applied correctly, they won't leak until you break the seal!
2) Improper valve cover gasket bolt torque. Even tho the rubber gasket provides some tension on the cylinder head bolts, the spec is 4.3-5.75ft-lb. They easily loosen, or are extremely over tightened when repaired.
3) 1 & 2 are compounded by the huge rearward angle the v6's are tilted at. Nearly 30* in many cases.

So I'm sick of it. Sick of hearing about it. Sick of most of us considering it a "routine maintenance" item that should be replaced every time someone is going near them. "Oh well you're getting X done, Have them do the VCG's before they start to leak!" etc.

Here's how I think we deal with it once & solve it for the last time.

Supply list:
Ultra Black RTV. RTV is *the* gasket "brand" of choice by everyone. Ultra Black is a premium line, and Permatex's most oil resistant RTV gasket. Even better. It is apply, set & go. (Non-premium RTV's need time to setup when mounted & some need to be re-torqued.) It could take 2 tubes. I used 1 Spray 13oz can.
Thread Locker (Medium - Loc-tite & Permatex Blue)
M7-1 Tap
Acetone, Paper towels, Q-tips. (Ya, ya Alcohol works, Acetone just eats oil so much faster tho! Ventilated area for both)
Scraper (or something with a flat edge you can level with)


1) Clean the gasket mating surfaces with Acetone. I find you can push paper towels through the groove, but a few Q-tips make very short work of it & you can be sure you've cleaned it thoroughly.
2) Completely fill the groove with RTV & scrape it flat so that it's a flush surface.
3) Run your tap down the threads of the valve cover bolt holes. This will clean the threads up.
4) (After the RTV has cured - 24 hours) Apply your "normal" 1/4" bead of RTV as a normal application.
5) (IMMEDIATELY) Put valve cover on & bolt it down. Since we're no longer using a "light pressure to seal" gasket. Torque the valve covers down to say 18-20ft-lb.
Using online calculators: The stock bolt & hole threads have a Recommended Torque of 15.2 ft-lb & Maximum Torque of 20.2 ft-lb (Not freaking 4-5ft-lb!?)

I do not think it would be wise to drill & tap for a larger size, tho someone could. It'd be hard to drill large enough to have good threads, without having some huge bolt running down it. (I just don't think there is any reason for like an M10. Those would hold 40-50ft-lb! That's above the OEM head gasket ranges!)

Anywho... That's what I did.

If someone had some money, you could also weld, or JB weld the groove full.
JB Weld is awesome on Aluminum. They expand at virtually the same rate @ the same temperature. Tho admittedly, I would not bother with going that far.
I also highly recommend getting to know the local nut & bolt house. I replaced every accessabile externial nut & bolt on my engine with better hardware for a grand total of about $30usd. Replacing all the OEM valve cover hardware should only cost a few dollars. Including the rubber backed metal washers.

[Eye8Pussies]

so basically you're saying that instead of using the rubber gasket, just use rtv sealant and let it dry first? sounds workable....

but by the same token, I didn't find the oem design to be too shabby either...though you're right, for the rvc, the angle of the engine design makes it tough to get to, and easy to overtorque


I would add as a recommendation that if someone was to do this, to get some new valve cover bolts before torquing them to over factory spec to get the rtv to stay down- after over 10 years dealing with the heat of the engine and the lack of re-crushing for the crush washers, at least one or two will snap- and that would not be a good thing if it should happen on the rvc


and good to see you're back to help out toysrme

[SnakeyeS]

welcome back to the forum.

[RedPhoenix]

hes back.

Good guide, i always thought 5lbs was shaddy.

[Camryamnesty]

WOW he is back!!! Glad to see that.

[davemac2]

I think 20 ft lbs is way too much. You risk warping the head. Preformed gaskets are often RTV themselves, so I don't really see your point. RTV alone can leak just as bad as well. Using a threadlocker is probably a good idea to prevent the bolts from losening. Using an accurate torque wrench and re-torquing those bolts every few months is probably the best thing to do. Applying RTV and scrapiing it flush on the cover is not going to help especially if the cover surface is not completely flat. I think the better way is to apply your RTV, let it skim over, then install the covers and snug down the bolts by hand tightening only. Next day, torque the bolts down to spec with a good torque wrench.

Just another opinion of course.

dave mc

[Toysrme]

Dude... It's a valve cover. There's nothing to warp. You'd snap the bungs off, or long since have stripped them out before you warped it off using the Tea-tiny M7-1 bolts.
It's not like bolting half a head down at 35ft-lb, and the other half down at 100ft-lb.

[sanfelice]

I'm going through this right now. Bought my standard issue RVCG and was about to replace today. Any advice on doing this job, in general? Do I remove the timing belt cover to remove the valve cover?

Thanks.

[Tony the Tiger]

Originally Posted by davemac2

I think 20 ft lbs is way too much. You risk warping the head.
dave mc

How do you warp a head from a few 6mm bolts? If under any circumstances, we would think that those puny 6mm bolts would snap off before it can warp a hunk of aluminum from pure shear forces

[Tony the Tiger]

What I noticed over the years is that the valvecovers of the 1MZ uses bolts that are limited in threads. Once you get to the torque specs, the threads are bottomed out and overtorquing them doesn't further tighten the cover anymore. Once you overtighten these bolts slightly, they snap because the threads are fully bottomed out.

The gaskets shrink and harden over time; and because the bolts have limited thread travel, you cannot compensate for the shrinkage!

With the turbo, I once had a poor crankcase venting system and I had quite a lot of crankcase pressure. I also lacked an oil cooler which means elevated oil temps. My fresh gaskets (already torqued down with a bead of Ultrablack sealant) would start to leak after a few weeks time...

My approach was quite simple actually. I bought a bunch of washers and I spaced out the valvecover bolts so that I could put more torque on them. By spacing the bolts, I now have more threads to pull the cover down without bottoming out. With the bolts spaced out (I have about 2 washers under each bolt), I could literally crush the stock gaskets until there was almost no gap between the cover and the cylinder head With the RTV sealant, stock gaskets and the much added torque, I had no problems after a years of boosting. Just another suggestion

[midnightmach]

So is this a problem all v6's owners should know of? I am just starting to learn more about my 3vz, is there a chance it is leaking, or would i know about it? It seems all you 1mz guys know about this problem. Help a noob out .

[Toysrme]

Most transverse v6's leak eventually. Every seal will fail, but valve cover gaskets are fairly common.

[green94camry]

I just did my front V6 gasket this afternoon. 184,000+ miles and the gasket was totally wasted. I bought a new OEM gasket at the dealership last week and installed it today.

One thing I noticed was that the factory used very very little silicone to seal the cover, the only place I saw silicone was on the hump for the cam seal at the front just behind the timing belt cover and the other end of the valve cover arounf the oil filler section. Other than that they barely used any type of sealer on these. Mine is a 94 1mz so I dont know about newer models but I bet there were some improvements to how the valve covers were sealed to the heads later on.

So I scraped off any sludge and sealer from the head surface getting it as clean as I could. Then used rubbing alcohol to flash dry and clean the surface. Then I pryed the old gasket off the vavle cover and it was really dryed up, and flattened. Cleaned the valve cover surface just like the head . Applied a small bead of silicone into the channel that the gasket sits in and stuck the gasket in and coated the gasket itself with a little more silicone.

Then I applied a good bead of silicone around the cylinder head gasket surface. Waited about ten minutes for slight curing and then installed the valve cover making sure the holes were all lined up I seated the valve conver by hand. I then installed the bolts finger tight and went and had dinner. Came back out 2 hours later and torqued the bolts to specs about 12 Ft Lbs, but as someone mentioned about the threads only go down to a certain point so you can't overtorque the bolt and ruin the gasket or force out all the silicone. It takes all the guess work out of the torquing of the bolts. Just make sure you do torque them to the factory spec and not LESS!!!

Tomorrow the silicone will be fully cured and that cover will not leak again for a very very long time. I am going to do the right valve cover next week, and change the plugs while I am there. Other than removing the upper intake wich is a piece of cake anyway I'll use the same proceddure, new factory dealer gasket and bond everything together with RTV Permatex Black High temp silicone. The rear gasket is leaking like a sive all over the block LOL!!! The front one was too, But I think the rear is worse because it gets hot back there.

Really only takes a 1/2 hour to change the gasket once you have access to the bolts. Remove plastic cover for the front and upper intake for the rear.

[sanfelice]

Originally Posted by green94camry

I just did my front V6 gasket this afternoon. 184,000+ miles and the gasket was totally wasted. I bought a new OEM gasket at the dealership last week and installed it today.
Just make sure you do torque them to the factory spec and not LESS!

thanks. i meant to say that i'm doing the front, but i will prolly have to do the rear, too. btw, my 94 has almost the exact same mileage as yours, so these failed right when they were supposed to


i'm doing my FVCG tomorrow morning. so, for the front, only the obvious stuff to remove?

thanks for the write-up.

[Toysrme]

Guys, if you'll run a tap down them. They'll accept a bolt as far down as you care to take it.