Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Valve Cover leak, how serious can it be?

Hey fellas,

My uncle has a 1997 Corolla that has been sitting on his garage for about 2 years. We jump started the car and after a while recharging the battery, we saw fumes coming out from the engine. I then noticed that there was oil all over the front of the engine… From what I have found in google it seems that this is a valve cover leak. How serious can these be? Are they easy to fix? because my uncle is thinking on calling the junkyard.

The valve cover leak is maybe the easiest to fix. Removing the valve cover requires maybe a few screws or bolts and removing a few other pieces that connect to or lay across the cover. Maybe an hour’s worth of work?

however, if the valve cover is leaking, then the condition of other rubber seals are also in question. I’d also consider changing the oil with a high-mileage oil or add an engine oil stop leak product to help recondition those seals.

Good Greif…PLEASE dont junk an otherwise good vehicle because of a 9 dollar gasket… Simply remove the bolts holding the valve cover on…and replace the gasket.

The only thing you need to devote time toward in this service is cleaning the cylinder head gasket mating surface… Use a solvent or carb spray or Brake cleaner on a rag and wipe any oil residue off of the gasket mating surface on the engine…the shiny gasket surface exposed when removing the cover…

Next I always use a pea sized dot of RTV silicone gasket maker wherever there is an Arch…like over the cams you will see the gasket arch over it…you put a small dab of sealant at those corners…

Then just reinstall the valve cover gasket…tighten bolts…de-grease engine (Optional) and GO…

Put it thisa way…I had my Girlfriend do hers while I monitored things…She had no issues what so ever and had a huge smile on her face the rest of the day feeling empowered…you will have the same feeling when you finish. Then she did her own brake pads too… Spent the rest of the day trying to explain how good it felt too…which is why I hold “class” every now and again…to pass on the empowerment…

This is as minor and easy as it gets really…aside from changing a lightbulb


Thanks a lot guys! Glad I came here, otherwise we would have made the mistake of junking the car. We will get it fixed now! =)

No worries. You tapped into a DEEP Deep well of knowledge in this site. If we havent seen the problem it probably doesnt exist. Many of us are Pro’s…Semi-Pro, Super Shade Tree or what have you type of Mechanics and Engineers and even a few Airplane mechanics.

Like I said…if we collectively havent seen or directly dealt with the problem…it probably doesnt exist.

Good Luck with the car…Valve Cover gasket is CAKE… Think “Nike” …Just Do It… haha


I had a 1965 Rambler that had to have a new valve cover gasket every year. The dealer replaced the first one under warranty. From then on, I did the job myself–I could do it in less than half an hour.

Every YEAR? Can you say warped Valve Cover? Yipes… Oh The Rambler 6 cyl… Good little workhorsey

The valve cover was probably warped. No more than a gasket cost and how little time it took to change it, I never looked for a new valve cover. I had later AMC products with the same engine and didn’t have that problem.


After being compressed for years, gaskets reform themselves into the shape of the cavity they’re in and lose their compression and ability to seal. The space under the valvecover being pressurized, oil weeps through. The condition is perfectly normal on older engines, and very easy to correct.

One caveat: don’t overtorque the valvecover nuts and break the studs off. They’re typically torqued to about 10 lb-ft, about half what a typical sparkplug is. Snug them down, but don’t try to get them as tight as you can. They don’t have to hold the engine in, just compress the gasket.

Here’s a drawing of how it all goes together.

In addition to the advice above, I think this engine has two half moons, one at the end of each camshaft. The new gasket will come with them, but I have heard of the old ones coming out and falling to the ground without the owner noticing them. They see the new ones in the gasket kit but don’t know where to put them, so they end up with a giant oil leak.

I can’t tell from SMB’s drawing as it doesn’t expand when clicked on, it stays a thumbnail, at least until he comes back and fixes it which I know he will.

Here’s the link to the source of the drawing.
You can click on whatever exploded view diagram you choose, and expand it to full size from there.

Apologies for taking so long. I took the day to sit in the sun and try to photograph bees to identify the specific species. Really.

My car is an early 90’s Corolla, 4afe engine. I’ve replaced the valve cover gasket a couple of times over the years b/c of leaks. It’s an easy job, takes me maybe 45 minutes. It’s important to fix, not just b/c of the mess and smoke, but b/c the oil can leak onto the timing belt. That concern would only apply of course if your engine version uses a timing belt.

As mentioned above, replacing the gasket is a little tricky. There’s those half moons for the camshaft, important to get those replaced and oriented and installed correctly. And also near the camshaft you have to apply a little rtv sealant in a couple spots where the gasket doesn’t quite reach. This is all well-explained in the factory service manual procedure.

One more thing, be sure not to over-tighten the bolts when you replace the cover. Only to the factory service manual torque recommendation, no more. Otherwise you risk warping the cover. Best of luck.