2000 Chev Impala 3.8l Intake and Valve Cover replacement

Hey guys, so I have my 2000 Chevrolet Impala 3.8l with around 244,000 on the body and around 90k on the engine and transmission. I have this problem with the valve cover gaskets leaking pools of oil on top of the engine and its gotten to the point where I can’t even add oil to the thing because the oil is up past the spark plugs, I just haven’t been driving it for the past few weeks. The coolant is also looking a bit scuzzy too. I would’ve done this sooner but I didn’t have the money before to take it to the shop and I didn’t have the time to replace it myself since I’m working 6-7 days a week. I went and talked to the most renowned mechanic in town and told me the best option would be to replace the valve covers and the intake manifold at the same time, which he said will run me around $600 or so. Is this a pretty accurate price estimate? I’ve always wanted to try to tackle it myself because I’ve taught myself a lot about cars and did some repairs on the car in the year I’ve had it, but I don’t really have a garage and my time schedule is tight, as well as my wallet. Do I really have to replace both of them? I know the valve covers are bad, but there’s no oil that goes through the intake, so I’m not sure whether the intake is bad or not (I have no vacuum leaks, or system too lean codes). Is the old man suckering me in to doing 2 jobs to make me shell out more money, or is this really a situation where I have to bite the bullet and replace both?

“I can’t even add oil to the thing because the oil is up past the spark plugs,” - OP
Seriously? Are you aware that this is bad for the engine?

Replacing the valvecover gasket should help, but it really isn’t the root cause of your problem. I’m betting that the cylinders are so worn and the rings so tired that the combustion is blowing combustion gasses by the pistons faster than the PCV system can relieve it. That builds up pressure under the valvecovers, which are connected to the crankcase via the oil return channels through which the oil that lubes the valvetrain parts drips back into the crankcase, and the pressure pushes oil past the tired, too-long-compressed gaskets.

While there isn’t any test specifically for the oil rings (for blowby), I recommend you start with a compression test. If your compression readings are way down and/or uneven, that’s a pretty good sign that the engine is just plain worn out.

In summary, if the pressure under the valvecovers isn’t relieved, new valvecover gaskets will likely be of temporary effect at best. And if the source of the pressure isn’t corrected, the pressure under the valvecovers won’t be relieved.

And if you’re really overfilling your oil, stop doing so. If the oil level in the pan is too high the crankcase can whip it into a froth that the oil pump can’t effectively pump and that cannot maintain the necessary pressurized fluid barrier between the sleeve bearings and the corresponding wear surfaces on the crankcase, the rods, and even the camshaft(s).

From what you describe, it sounds like all you need to have done is have the valve cover gaskets replaced.

And you’re right. The intake manifold doesn’t have oil flowing thru it. So there’s no reason to replace that gasket.

The price to just replace the valve cover gaskets is about right.

The left side valve cover is pretty easy to remove. But the right side valve cover involves removing other engine components along with tilting the engine in order for it to be removed.


I’m assuming by replacing the valve covers and intake manifold, you mean the gaskets that hold them tight to the engine, not the parts themselves. If I had this problem, I’d probably just do the valve covers first, see if that fixed the problem. You might get lucky. But if you trust your shop, they can see the engine, I can’t. If you trust them probably best to just go along with what they recommend. $600 is small change for engine-fixing these days.

As mentioned above by TSM, the PCV system can get involved with oil leaks too. I’d probably have the shop replace the PCV as part of this job.