I'm wondering why you couldn't fill the groove with RTV and just screw the covers down. Anybody tried this? If so how did it pan out? I guess the big drawback would be getting it out if you had to.

Make it easy on yourself, use the the rubber valve gaskets.
Available from the Fiero Store, mention you are a member of PFF and get a 10% discount.
They don't leak at all.

Jetman, I usually do use the molded rubber gaskets and you're right, they don't leak. I have a set of Felpro's on hand. This question about RTV was more just wondering if it would work. RTV has become almost a universally applied sealant in the auto industry. Last month we started using it on the 2005 3800 oil pans. I just thought maybe a forum member had tried it and would share the results.

Given the pain in the butt to replace the valve cover gaskets, I wouldn't chance it. It may be that the difference in thermal expansion rates of aluminum and iron would make an RTV seal fail prematurely. The silicone rubber FelPro gaskets hold up very well.

JazzMan

The RTV would probably work fine if the covers had a flat mating surface and I would actualy use it in that case. I noticed that there was a considerable amount of extra depth to the rubber gaskets to allow for compression as you tighten down the valve cover bolts. I'm unsure if the RTV could be built up enough as I don't have much expierience with it.

GM tried RTV Silicone on the L4 cover gasket. The term Abysmal Failure accurately describes the result.

RTVS is a bad option in many cases. It needs a certain amount of gap to actually work right. Example: Valve covers made for RTVS as the only sealer had dimples etc to create a controlled space for the RTVS. Even then it often doesn't work well.

Many ill informed "mechanics," including many so called pros, use RTVS all over the place. They very often end up with comebacks and lost business as a result. There is no substitute for using the correct gasket and, if needed, the correct sealant. Many gaskets made today are to be installed DRY or with a thin sealant like Permatex High Tack spray on adhesive just to help hold them in place durring assembly.

One of the few places where RTVS is actually called for is the overlap in multipart oil pan gaskets where the silicone end parts meet the side parts. Or in places like the Mistubishi 2.6l OHC valve cover gasket that has a couple sharp corners you can't seal easily without it. (This engine was used in Dodge Caravan for a few years.)

Since you didn't say... Let's assume for the moment you are working on an assembly line at a GM plant... (One of which is here at Boxwood Rd in Newport DE.) This isn't a GM bash... They all work like this...

Even if the stuff coming out of your sealer tool looks like RTVS Don't asume it is the same stuff you buy at retail in the parts stores. Even if it is, the stuff may be yet another recall destined attempt to save money. All the carmakers care about is saving money up front. They know that even if they issue a recall later, very few of the defective cars will actually get fixed. It is very rare for a recall to cost more than what they saved up front. Even when a recall affects millions of cars, only a few thousands get into the shop. If they actually had to fix all the aplicable cars, the cost would make stock holders barf and call lawyers real quick. NHTSA is mostly a joke in the real sceam of things.

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The only thing George Orwell got wrong was the year.

The Ogre's Fiero Cave (It's also at the top of every forum page...)

I had a 84 Chevy Celebrity with the 2.5 engine. That whole engine was sealed with RTV. I prefer gaskets over RTV, and many gaskets now are just preformed RTV silicone, but if you use RTV correctly it will outlast gaskets in many cases. The sealing surfaces have to be absolutely clean of any traces of grease/oil and of old RTV. Some stampings such as valve covers or oil pans are designed with grooves or spacers stamped into the sealing surface and such to accomodate the use of RTV.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Logic is a systematic method of coming to the wrong conclusion with confidence!

Ogre, once again you are right on the money......no pun intended. I am a fastener tech on the 3800 build line. We went to RTV on the oil pan to save money and the process ended up being such a cluster f**k that it is now costing more than the elegant molded silicone gasket it was meant to replace. Looking at the Fiero valve covers and the groove all around the perimeter I got to thinking that filling the groove with RTV might work, but would certainly be messy. After thinking about the potential for major rework and pia I've pretty much abandoned the idea. And oh, we are still using RTV on the 3800 pan and will continue to do so because some engineers even in the face of disaster can not admit they had a bum idea.....oh and did I mention the 200,000.00 application machine? and going from 1 person to install the pan to 3 people? GM seems to have an official policy of grasping every penny while hemoraging dollars.

If you have the "beaded" vavle cover, I think you have one of the ones GM already tried and failed sealing with RTV. As I remember the OE gasketed ones had no beading or dimpling. The beaded covers can't use certain gaskets. I forget which right now. I think you can't use the silicone or rubber with those. You need something soft like the cork composite so the bead can sink into it. There is a TSB about them someplace. They are also mentioned in the gasket (Felpro etc) parts books I think.

Myself, I'd try to swap a beaded cover for a flat one (These just have a folded lip around the edge. the seal area is all flat.) and use the rubber or silicone gaskets. The silicone gaskets have metal inserts that limit clamping pressure and reduce the chance of bending the cover. As long as a cover is true to start with those are the lest likely to ever leak again. I've used rubber and it is good but can leak. Not from the gasket failing but the screws working loose. I'd recomend a lock washer but I'm not sure they will solve the issue and do it without chewing up the cover a bunch..