valve cover gasket with or without silicone.?

**promdiboy** · July 5th, 2004 02:27 AM

Oil started coming out from my valve cover and half moons, when I started using 5w-30 oils. My suking mekaniko said I should buy a new valve cover gasket and half moons. Since I live in the province, I could not get orig mitsu parts here. What he did was put silicon on the valve cover gasket and hal moons. and so far there has been no leaks.

My question is what's the disadvantage of using hi-temp silicon vs new gaskets? should I replace it asap even if itt does'nt leak anymore?

**yebo** · July 5th, 2004 10:26 AM

pare,

i personally would not recommend using silicone (any type) IF it is in contact with oil or fuel. there is nothing wrong with its use on the engine since silicone sealants are basically chemically neutral (i.e., they don't react with most substances it is in contact with), BUT when in contact with oil or fuel they tend to cure longer. longer here means a few days before it sets completely. now of course there is nothing wrong, as long as you do not use your car for a few days. but if you use it immediately after applying silicone, there is a danger that the silicone which is still soft can migrate to the oil passages or fuel lines. this can lead to a blockage of oil or fuel. if the blocked passage happen to feed oil to a bearing, patay kang bata ka.

so the verdict? YES you can use silicone, but make sure the surfaces are free from oil and you don't run the engine until the silicone has fully set. if it is free from contact with oil it should set completely within 2-3 hours. but if you intend to run the engine right away then it gets into contact with oil, and that prolongs the curing process. it's like playing russian roulette - will the silicone set in time and not block the oil passages, you can only wait for the results to happen.

**speedyfix** · July 5th, 2004 11:32 AM

ok lang na linagyan nya yung existing mo na gasket ng silicone. pero if you buy a new one do not have him apply it all around. silicone should only be used in the corners of the gasket to form a proper seal and not over the whole surface.