johntm77

I'd like to know your thoughts on my valve cover gasket repair. I have a 3.0 in my 94 4runner with leaky valve cover gaskets. They were replaced by a shop a couple years ago but continue to leak. I spoke to a knowledgable Toyota mechanic who said they are notorious for leaking and the only thing he's ever had fix it was the gasket maker "the right stuff."
My question is this: Should I only use one continuous bead of the gasket maker or should I use the OEM gasket with gasket maker in the areas the FSM instructs you to put it?

I have quite a bit of automotive experience and in my experience, using a combined gasket and gasket maker is good way to create a leak. One or the other is typically recommended.

I am inclined to only use the gasket maker to create the best quality seal. Would this work? Are there any issues with the height that not installing the OEM gasket would give you when torquing it down?

Any insight is appreciated. BTW, this is my first post, but this is a great website. I've used it for numerous repairs on my 4runner!

DeathCougar

iTrader: (23)

For whatever reason, Toyota decided to make their valve covers out of plastic. So, they work just like the AMC 258 plastic valve covers. IE, not very well.

I would use a new gasket, and just a little FIPG at the corners. If it still leaks like crazy, get new valve covers from toyota.

GSGALLANT

x2... I would use new Toyota gaskets, and "The Right Stuff" (my favorite FIPG) at the locations indicated by the FSM. That's how I did mine, and I had no leaks up until I sold my 1993 4Runner. I don't think it's the kind of joint that you'd want to use just FIPG on. If I remember correctly, there's not much width there for a flat sealing surface on the covers.

Also, make sure to follow the recommended torque sequence and torque values. That goes a long way in making sure finicky joints like this stay leak tight.

johntm77

Thanks for the replies. I guess I'm concerned the gaskets will leak again if I stick to the factory service manuals instructions. The leaking gaskets are less than 2 years old and have been leaking almost since they were installed. They are OEM gaskets with the gasket sealer in the correct spots. I suspect my valve covers are warped just enough that this will not be enough and I don't want to have to redo this job!

With that said, has anyone had any experience of only using a gasket maker for these valve covers? I would think it would hold up better and make a better seal. Especially since the typical repair hasn't held up.

Bullydog95

High tack sealant in the can works great!

DeathCougar

iTrader: (23)

Gooping a bunch of sealer all over it is NOT going to fix the problem. If the valve covers are warped, you NEED new valve covers.

OutlawMike

I did a rebuild on my '89 V6 Runner two years ago, due to a dropped valve seat on the number six intake valve. The motor had been leaking oil from the valve covers for years and the engine was a mess. I pulled the whole thing, rebuilt it, cleaned it, painted it, and wanted to fix the problem.

The gaskets for these valve covers are a molded rubber, not sure of the exact compound, but they are not fiber reinforced or contain any type of stiffening compound. Toyota put metal inserts in the ears of the valve covers that are used to bolt the cover down. The metal inserts act as hard stops. When you tighten the bolts you lock down on the metal inserts and do not load the plastic in compression. This keeps the plastic from creeping over time while under load and also allows a compression stop for the molded gasket. When these hards tops lock out, there is a gap between the plastic valve cover and the head surface, the plastic does not touch.

If you use just gasket maker, this gap will still be there and the gasket maker would have the opportunity to squish out sideways. If it is really thin, it might drip out due to gravity before it sets.

What I did is put a thin bead of gasket maker down in the groove all around the bottom of the valve cover. I then put a thin layer of gasket maker on all of the mating head surfaces. Then I quickly assembed everything before it started to set. Normally lubing the gasket like this causes problems, as the gasket will slide out sideways under load, as in a cork gasket on a trans pan. But, given the hard stops in this design and the designed in gap between the cover and the head, I thought that the gasket would cooperate as the compression of the gasket does not increase past the hard stop point that Toyota designed in.

I used the blue FelPro gaskets.

It worked great, until I went in to check the valve adjustment. Damn, those gaskets were glued to the head. I had to scrape for hours to get all of the torn gasket material off of the head surfaces and out of the cover. I was impressed with the sealing, but if you are going to take them off again soon, maybe wait until the second time.

The set I have in now has been in for 18 months, no leaks. I replaced every seal on the motor, not a leak on that thing, as of right now.

Good luck,

Mike

scope103

I've used just the rubber gasket plus RTV where the Service Manual says to put it. The advantage of the Right Stuff is the incredibly speedy cure, the downside is the cost. (I let the RTV go overnight.)

What I did wrong the first time is that I failed to get the head surgically clean. RTV is fairly sticky, but it won't stick to oily metal. When I redid it I used paint thinner, but you might have even better luck with something highly volatile like brake cleaner.

For me, the second time was the charm. Once I properly cleaned the sealant area, the leak went away for good.

turborich

I had a similar problem, not on a Toyota (it was a 2.9 liter ford) but the same idea would apply. On that engine the valve cover gaskets were notorious for leaking & after doing them 3 times I finally fixed it once & for all. I used the gasket & I applied a thin coat of RTV on both sides (don't gob it on though) Also don't go to tight when you tighten them down. I used a nut driver just to snug them up until the RTV had a chance to form up & then finished only with the nut driver in the correct sequence. I never had a leak again. I don't see why it wouldn't work for this engine as well.

johntm77

Thanks for all the great advice! I've decide I'll use the gasket with a thin coat of RTV on both sides. Sounds like people have had success with that. Thanks again, John

BTW, I was just going to let this go indefinitely. The leak is so slow that in 3 months between oil changes there's hardly a noticible amount of oil missing on the dipstick. Oddly enough though all the oil that does slowly leak out ends up dripping down to where the passenger side lower control arm bushing hinges with the frame. That camber bolt actually loosened up from being soaked in oil for a year plus and I started getting a loud pop when braking hard or slowly turning left. I took it to the dealer to get it aligned and to diagnose the pop and they told me it was my aftermaket Rancho 9000 shocks hitting the bumpstops! The pop went away after alignment for about a week and then started up again, even worse. I finally got under there to check it out and the rear passenger side camber bolt was hand loose! I immeadiatetly took it back to the dealer and demanded a free alignment and proper torquing of that bolt. I cant help but think that oil dripping on it for months wasnt the source of it. All the other camber/caster lwr control arm bolts are dry, and tight. I know thats probably more than ya'll wanted to know, but it actually took me a little while to figure all this out. And the shocks were not hitting the bumpstops. I had dinged the side of each shock when I replaced the lower balljoints several months back.

It's funny because you go to the dealer and they really don't know better than anyone else. I also can't help but think as your vehicle model gets older that especially the younger mechanics haven't had as much experience with these models, like my 94 4runner. Not only that but you start seeing parts go out that aren't typical and that seems to through them off. Anyway, maybe this will help someone that has a pop in thier front end combined with a pasenger side valve cover leak!

Thanks, John

1990yotapickup

can i use permatex red, grey or black sealant