Hi all,

I just picked up a 2001 Chevy 3500 6.5L Diesel Cube van (180,000km - 111,846 miles). previous owner said he took it to a mechanic and said there is oil in the coolant, but he says it's from an oil cooler gasket leak. no leaks whatsoever externally. some people say it's a blown head gasket, some say it could be the oil cooler gasket.

I've tried to search for an oil cooler gasket but can't find anyone that sells this. kind of strange.

Looking to start with an oil flush and a coolant system flush, and inspect the oil cooler gasket. trying to do the cheaper "fix" first before I go for the head gasket. I haven't tested the head gasket yet, but will be doing that after the flush.

any recommendations? this is my first diesel truck that I will be using for work, it's in pretty good shape, but running a little rough. has been sitting for about 6-8 months, just got it started yesterday.

After reading some threads on this engine, I'm getting this sick feeling in my stomach thinking I should have went with a ford or dodge diesel. this engine seems to have a pretty nasty reputation!!

Last question! I was given a shop service manual (2 big bastards), about half a million pages it's for a 1997 6.5L diesel, have they changed at all up to 2001 ?


thanks so much for any help and/or tips (other than I should have not bought it)!!

 

Hello first of all the biggest reason IMO that the 6.5 get a nasty reputation is that it's not a powerhouse like some of the Fords and Dodge and Duramax engines however they get awsome fuel mileage compared to the competition, I've had a few of them and still have my 93 and love them personally, my 93 gets northwards of 22 MPG highway.

And if you are talking about the seals for the oil cooler lines coming out of the engine block to the cooler there are o-rings inside the fittings they tend to leak with age if you replace these you can get them from the dealership for a few bucks and do get the retaining clips while you there.

 

There really isn't any oil cooler gasket that can let coolant in. Like a blown head gasket

 

Oil in coolant only, or is coolant in crankcase too?

Although wishful thinking, I suspect they blew smoke up your cash. Could be the in-tank cooler is leaking and there is a gasket used to seal the in tank coolers to the plastic tanks but that usually causes external coolant leaks. See videos.