newhandle

03 c240. I'm hearing conflicting info on this. Is it necessary to give the new gasket a doze of gasket sealant? I have some Permatex black that I will be using to reseal the breather covers, but would it harm or make any difference if I used it to seal the valve covers after putting the new gasket in?

Thanks

TruTaing

MB does not have a gasket for the recirculating valve covers - it is sealed with a sealant and you'll be fine using Permatex black

Glyn M Ruck

If you are really talking about the cam covers then Yamabond 5 or 6 works wonders.

pcy

For valve cover - sealant should not be used; only the gasket.
For breather covers - use sealant.

Glyn M Ruck

I generally agree with that comment pcy - but the V6 engines are inclined to weep a little at those covers & Yamabond fixes it. The world of racing could not survive without Yamabond. You won't find an F1 pit without it. Yamabond is not like Permatex crap. It is designed to seal alloy casings with no gaskets that might be subject to vibration. It remains pliable at high temp & is easily removed.

JoeVal

I would not use Permatex for other that sealing a vessel plug or bushing. Materials to form gaskets in place have been long ago developed and are now well proven in desired viscosity, curing process and ease to apply. Permatex flows way too easily for this purpose and is messy (to the point that can contaminate vessels sealed by delicate gasket-on-lip joints). Anyway the technology is there and the chemical specialists (Permatex mother company included) offer a wide array of products at competitive prices and for easy application. Availability, ease to apply and vendor's recommendations should show the way.

By the way, thanks for the Yamabond pitch.

JV

newhandle

What if I wanted to use the gasket still? Can I use yamabond to top off the gasket before bolting down the covers?

Carsy

I have always used a pliable liquid gasket ( Loctite) for the sealing of tappet & sump joint applications. So long as you do not over apply & contaminate the oil .

Glyn M Ruck

Yes - I recommend using it in conjunction with the gasket for a permanent but easily broken seal the next time you want access.

newhandle

sounds good. Thanks

danev6972

Just sealed mine with permatex not too long ago. No problems. Not messy at all.
Those bolts are delicate though...I stripped on of them. Be careful with them.

ncmudbug

Kind of a humorous story: All this reminds me of a time I was racing and was at my engine builder's shop when he was working on his Datsun sedan race car (it was long enough ago that it was a Datsun, not a Nissan). Silicone sealants were very popular and people used them almost everywhere. Well he couldn't get his car to start because it wasn't getting fuel. You could hear the fuel pump run, but it took him a while to find out why it didn't pump any fuel. He started taking hoses of his fuel cell and one of them was filled with a rope of silicone sealant! He had either used too much or it collected in his cell over time and assemblies and disassemblies and finally his fuel pump became a silicone sealant pump! BTW - I'm ordering tube of Yamabond to try that out. It sounds like good stuff.

I guess the moral of the story is that silicone isn't always the best sealant (it was more susceptible to attack from gasoline than people thought) and to be judicious with the use of any sealant.

Glyn M Ruck

Acetic acid curing silicones attack alloys & silicone in general if ingested by the engine will destroy your O2 sensors.

ericgoh

+1 to Glyn's recommendation to use Yamabond. I replaced both valve cover gaskets in February (with aftermarket seals - Victor Reinz) and they just started leaking again. Checked the torque...even tried increasing the torque spec a hair but these seals are weeping a bit. Just order OEM Bruss seals to replace them and I'm definitely using Yamabond this time.

ericgoh

Hey Guys,

I just removed the 8 month old Victor Reinz leaking valve cover gaskets. I noticed that the seals are slightly melted and have a distinct burnt rubber smell. We had an extremely hot summer here in Texas with 90 days of 100+ temps but I didn't think that would be enough to melt these gaskets. Also, the engine seems to run a bit hotter than it used to - hovering around 95 degrees (perhaps hotter, although it's hard for me to read accurately). But, the fan does eventually kick in.

Any chance this is a thermostat issue causing the premature wear? Or, did I get a bad batch of gaskets? Many thanks!

FYI, I checked for codes but there is nothing stored.