kbourne

Hey Ramsir.

You mentioned you had an oil leak fixed by replacing your intake manifold? Did I read this correctly? It is my understanding that water and coolant run through the intake manifold so I do not understand how it fixed an oil leak. I am interested because on my 2001 Suburban 2500 LT it is leaking on both rear corners where the oil pan meets the engine block. The oil drips (on the passenger side) down the retaining bolts for the starter motor and along the bellhousing cover. I have replaced the valve cover gaskets, the oil pan gasket and the oil cooler gasket.

Thanks

Ramsair

So, I now have 4000 more miles on my Tahoe since having the intake gasket changed out - oil leak has stayed gone. I never did have any coolant in the oil or vice versa - from what I understand the coolant normally ends up in the oil due to the pressure being greater on that side of the equation.

If you do end up doing your intake gasket - replace the knock sensors and harness if you have that set up - no reason to have to go back later and do it again.

Good luck - chasing an oil leak from "back there" is no fun.

Chris

kbourne

KeithKman,

Ever get your leak fixed when you put it back in the shop? What was the problem?

KeithKman

They replaced the rear main seal. Still leaks. They replaced the drain plug and the oil cooler block plate gasket. Still leaks.

I even put dye in the motor before I took it in. I need to take it to another shop but I don't want to be jacked around anymore.

KeithKman

How much did the shop charge to replace the intake gasket? Or did you do it?

EDIT: I see they charged you ~$300.

KeithKman

How would I know if it's the oil pan gasket or intake manifold? I want to get the leak fixed once and for all without dumping more money into the Tahoe only to have it continue to leak.

I love my Tahoe, I just wish it didn't leak oil.

dh1

This is actually pretty easy to tell. Clean off the sides of your engine block and oil pan, then see if the leak is coming from the top or bottom.

If the sides of your engine get coated with oil, then the leak is coming from the top. If the sides remain dry, but you are still leaking oil, then inspect the perimeter of the oil pan for drips.

If you are a DIY mechanical type, you could do both sets of gaskets pretty easily for less than $100, and stop the leak fo-sho

KeithKman

It's hard to tell since the oil is everywhere towards the back of the block. The starter is covered in oil. When I pulled the air intake off the throttle body and opened the butterfly valve, there is a good amount of oil in and behind the butterfly valve. Is this normal or does it mean intake leak?

dh1

It's not uncommon to have some oil in your intake because your PCV is directed into the intake, directly from the rear of the driver side valve cover. You are likely overdue for a new PCV. It shouldn't be alot, but some isn't completely illogical.

Regarding the oilpan vs intake manifold gasket. I really don't understand the intake manifold being as big a source of an oil leak because the oil should only be getting into the intake manifold in very limited amounts. There are absolutely no oil lines that go into the intake manifold. If the gasket leaks, it would be more of a vacuum, and not a blowout...as the pressure inside the intake manifold is lower than ambient pressure while running.

My gut tells me that you are either leaking from your oil pan or your valve cover gaskets.

The point of my previous post is that oil leaking from the oilpan will NOT go uphill, it will simply collect at the lowest point and drip off. So if it is higher on the block than the top of the oilpan flange, it's coming from further up top (valve covers).

I am just thinking outloud, trying to help eliminate possible culprits.

I almost forgot to mention. When I bought my 2002 burb, the PCV valve had been pulled out of it's seat, so the crankcase was just venting overboard (rather than back into the intake). The result was a bit of an oily mess at the back of the engine. not enough to drip on the ground, but it coated the area pretty well.

KeithKman

Thanks for the response. Regarding the rear cover leaking, they replaced that gasket and applied RVT when they did the rear main. The truck leaks a lot less oil after they did the rear main and rear cover bit it still does leak. Maybe two quarter to half dollar size spots in a 24 hour period.

I replaced my PCV valve with the new updated one where there is no valve but rather a small hole. I did that about 6k miles ago.

I don't think it's a intake manifold leak because the truck starts fine even when it's cold.

The oil coats the starter and also covers the oil filter. It seems to be dripping from the bottom of the filter and from below the oil filter drain plug.