What is this leak behind the exhaust manifold?

toyota
corolla

#1

Car is 2000 Toyota Corolla with 87K miles. What is this leak behind the exhaust manifold (I think that’s what it’s called…it’s right behind the engine top cover)?


#2

Could you take another picture from farther away to show the location in the engine bay?


#3

@xaml
Appears to be a valve cover gasket leak. Pretty normal for a 2000 model-year car!
CSA


#4

I see a valve cover gasket leaking. The exhaust manifold isn’t even visible in your pictures.


#5

@xaml

That gasket is there to seal the seam between the valve/rocker cover gasket and the cylinder head of the engine. It keeps the oil inside. Gaskets age, shrink, crack, and generally lose flexibility. Then they leak. (That’s the MO of almost all gaskets!)

It becomes a problem if/when they leak enough to increase oil consumption and/or create a fire hazard when oil drips/runs onto hot engine parts (usually exhaust components).

My sources indicate that it’s only 1/2 to 3/4 hours labor for most shops to replace the gasket. The gasket/gasket kit needed should not be on the expensive side, either.

That gasket could have been weeping oil several years. A trusted mechanic should be able to advise on the necessity to replace the gasket now or in the future. Sometimes just keeping an eye on it at oil change intervals is the easiest/cheapest operation that makes the most sense.

A little bit of oil can make what looks like a big mess.

Bringing everything up to “as new” condition on a car that is 16 to 17 years old is generally not practical or affordable.

CSA


#6

Thanks everyone for the reply. I checked the oil level and it is fine but I will take it to the mechanic to get the gasket replaced anyways.


#7

I agree. And it’s running down onto the manifold.
What you’re seeing in the photos is (1) the plastic cover shroud, and under that (2) a stamped metal heat shield. Below the shroud is the valvecover, below the heat shield is the exhaust manifold.

The interface between the valvecover and the block, wherein lies the valvecover gasket, will be visible with the plastic shroud removed. You should at that point be able to see the seepage trails.


#8

If you do have it replaced, I’d have him check the valve clearances while the valve cover is off. Shouldn’t cost much more, once the valve cover is off. Make sure you aren’t double charged. It should just be the cost of a valve clearance check (a new gasket would be used anyway).


#9

@xaml, if the valve clearances need adjustment on this side, tell the mechanic to check the other side.


#10

If the valve clearance are off…is adjusting it complex? Can it cause more problems?


#11

This side?


#12

Checking the clearance is straightforward, assuming he knows what he’s doing. Adjusting it takes more work and may require some special tools, so make sure your mechanic is qualified. It’s very likely adjustment won’t be needed, but if it is needed it’s well worth doing it. Done wrong it could cause problems, that’s why a good mechanic is needed.


#13

There’s a possibility that’s a cam seal that is leaking too. That would be evident , yay or nay, once the valve covers are off . Doesn’t look all that serious. If it were my car I’d just keep an eye on the oil level and if the level holds steady, don’t do anything about it until summer. No fun having a non-working car in the winter.

I’ve had to replace the valve cover gaskets on my own Corolla 3 times over the course of 20 odd years, so a leak there isn’t uncommon. If you do decide to replace them, make sure the shop follows Toyota’s procedure from the factory service manual b/c it is critical to place some rtv sealant in a couple of places as part of the job, otherwise it will continue to leak even w/new gaskets. Best of luck.


#14

I’m pretty sure this is a 1zzfe engine.
That leak is probably from the timing chain tensioner.
It can be removed to replace the o-ring, which costs a couple of bucks.


Checking valve clearance is easy, but adjustment requires removing the cams and changing shims.


#15

It’s a 2000 Corolla. There is no “other side”. :grin:


#16

Mechanic said that he does see the valve cover gasket leaking and he will replace it along with an oil change but he does not think that is the problem of the “oil leak”. He said I had lost about 2-2.5 quarts of oil and because it’s been about 3500 miles since my last oil change and because the car has almost 90k miles, he considers that normal usage.

I drove to west virginia a lot (many mountains and steep hills)…the engine hit 3500 rpm…I wonder if that was what caused the oil loss.

I just can’t believe a well maintained engine (since i bought it used at 45k miles) burns oil at 90k…and I wanted to take it 500k.


#17

3500 RPM is totally normal.


#18

Do you check your oil regularly? Or was is 2 quarts low at the mechanic? That’s a BIG problem, of your making. How many miles per quart?


#19

@XAML How many times to you have to be told that your car will not let you over rev it. And if you read anything at here you should know by now to check your oil on a regular basis.


#20

I check the oil regularly…although this time, I forgot to do it for 3 months. Last time I checked it (back in Oct), did not see any oil splash.

When I pick the car from the mechanic, can I take it for a ride or should I let it sit until the “gasket seal” hardens?