The Best RTV for sealing valve covers

[firstq]

My 92Q is going back to the shop for resealing the passenger side valve cover - it has leaked twice in the last 12 months - last time it did not even last for 3 months (one oil change and it started leaking). Seems like it can not hold the synthetic oil (even the blended ones).

What specific RTV (brand and color - he has used the red one and it does not seem to hold the synthetic oil) do you guys use (so that I can recommend is to the shop as well) and if there are some best practices here (curing for 24 hrs , etc) that the shop should follow?

Thanks

[DAEDALUS]

RTV is good stuff. Holds satellites together for 15 years with daily temp cycles of 300 degrees or more, but admittedly without the shocks and vibrations your car endures. My hunch is that your shop is not spending enough time cleaning the mating surfaces of the covers. That is the most important step--glue doesn't stick well to crud and oil. They need to have the vast majority of the old RTV off both surfaces and THEN they need to degrease both surfaces repeatedly using a non-residue degreaser like Brakleen or contact cleaner. And I don't mean just spray it on. You need to wipe it down again and again with a rag soaked in the stuff. It's a shame to pay someone $65/hour to do this, but if they gave you a fixed quote on the job, that quote SHOULD include this labor.The facory RTV usually lasted 5 years or more. If you think there might be a difference in the RTV itself, you can get a large tube of Nissan factory RTV for $10 from Scottsdale. I've also heard good things about marine RTV, but again, I think the failure is in the process. A 24 hour cure should be mandatory if they warranty their work.

[DAEDALUS]

Also, make sure they're following the torque sequence and torque values. There's a bondline groove in the cover to prevent excessive squeezeout, but they should still be following the instructions to get the best bond.

[shaginator]

I used the red RTV in my own valve cover gasket job. I can't attest to how long it's lasted since it's only been around a month and a little more than 1,000 miles, but I checked this past weekend and it's holding up well so far. I use synthetic oil too.

Seeing that yours has leaked 3 times in the past year, I'm wondering if you're really getting brand new gaskets, or if the mechanic is just adding rtv to the old ones? The use of RTV on parts of the gasket seem more like "added insurance" than part of a fix.

And like Deadalus pointed out, the service manual specifies torque values and a sequence that guarantees even pressure on the gasket contact points. The sequence is very important; I'd say more important than the RTV.

[Q451990]

No gasket on the 92 - just RTV. The head and rocker cover design change with the 1994 model year to a gasket.

I've always used Permatex Grey - same as my local dealership. Nissan sells a gasket material that's more of a burnt orange color. I think the dealer uses grey since it blends in nicely with the engine.

The other important factor is the cure time after the car is reassembled. Just putting it together and starting it up is a recipe for disaster. That's what my dealership did the first time, and when I got it back half of the bead was hanging down over the exhaust manifold. You might have them complete the job and let it sit overnite before starting.

Heath

[911/Q45]

I used the red and spent several hours with a dental pick cleaning out the grooves. I had plenty of cure time while Scottsdale and I chased down all those nasty hoses under the plenum. Still sealed tight after six months and 5000 miles.

[Eswift]

2nd on the permatex grey.

someone mentioned RTV on satellites for 15yrs....RTV is also what they use to affix the reuseable thermal tiles to the space shuttle. apparently 23 years is a bit too long, or at least too many huge thermal cycles, inducing some fatigue along the way. now they know, one would hope.

[shaginator]

Quote »No gasket on the 92 - just RTV. The head and rocker cover design change with the 1994 model year to a gasket.[/quote]Ah! I stand corrected.

Just to add, even the teeniest bit of oil can destroy any chance of having the RTV stick to the metal and then cure. I noticed this after a goopy blob dripped onto a piece of metal that had a light coating of lube on it... most of it just slithered off and fell to the floor. What was left on the metal took forever to cure.

[nisstek]

I agree with all the above. Its gotta be clean and dry. Did they replace the 1/2 circle plugs in the back of the valve cover? I've had good luck with both the Permatex grey and the NISSAN orange. I wouldnt use anything else. If its something that's stand out visible under the hood I use the grey otherwise I use the tried and true orange. Orange goop everywhere kinda looks shadetree.

[firstq]

Thanks guys, I will debrief the tech on all the best practices mentioned here. This is still under warranty, so hopefully I am not in a hole for this one.