Rocker cover oil leak

[Ed H.]

This past week I had to replace the catalytic converter on my 1990 L-98 engine. I started to hear a load rattle coming from
the exhaust system. When I replaced the converter I found a major oil leak all around the front chassis of the car. I also began to see oil on my drip pan. I examined the area around the heads and found oil leaking from the rocker covers. This an original
engine and the rockers have never been removed. I checked the 1990 manual and found the 8 bolts on the rockers should be torqued to 90 inch pounds. When I addressed the bolts I found all of the bolts loose. If you have an L-98 engine with 60-65K
miles on it check the rocker bolts. Warning, do not over tighten them as this can crush the gaskets and cause more leaking.

[Joe L.]

Re: Rocker cover oil leak

This past week I had to replace the catalytic converter on my 1990 L-98 engine. I started to hear a load rattle coming from
the exhaust system. When I replaced the converter I found a major oil leak all around the front chassis of the car. I also began to see oil on my drip pan. I examined the area around the heads and found oil leaking from the rocker covers. This an original
engine and the rockers have never been removed. I checked the 1990 manual and found the 8 bolts on the rockers should be torqued to 90 inch pounds. When I addressed the bolts I found all of the bolts loose. If you have an L-98 engine with 60-65K
miles on it check the rocker bolts. Warning, do not over tighten them as this can crush the gaskets and cause more leaking.

Ed------


I think I'd recommend replacing the valve cover gaskets rather than just tightening the bolts. These gaskets are now 27 years old. GM #14088564.

[Mark E.]

Re: Rocker cover oil leak

Didn't L98s leak as delivered from the factory? My brother's '85 and '90 did.

It should be a point deduction if it doesn't leak.

[Phillip M.]

Re: Rocker cover oil leak

I had to replace the valve cover gaskets in my '86 when it had about 30K miles on it. This is an horrendous job! I checked with the Chevy dealer first and they wanted hundreds of $ to do the job. Parts naturally were cheap, but labor was about 6 hours as I recall. Issue is that R.S. cover entails removal of upper exhaust system to remove (and later install), the EGR pipe that goes over the top of the valve cover preventing it's removal. This pipe is held at the bottom connection by a crimp ring that can only be attached by having that portion of the exhaust system in your hands to get the crimp tool on it. Nasty job. I ended up making my own 2 piece ring held together with allen cap screws. Another case where if GM put in just a little more money into their product it would have made servicing a lot easier.

[Ed H.]

Re: Rocker cover oil leak

Phil and Joe, your both right. Normally I would have replaced the gaskets (Oh shades of my 57 rocker covers). So I lighted the bolts and guess
what, no more leaking. If it begins again I will replace them. Both sides are difficult. It is almost as bad replacing the sparks plugs.

[John M.]

Re: Rocker cover oil leak

Didn't L98s leak as delivered from the factory? My brother's '85 and '90 did.

It should be a point deduction if it doesn't leak.

Sigh ...