Intake manifold - mechanic says oil in coolant

I have a 2002 Chevy S10 ZR2. So my intake manifold gasket has a huge hole in it and is leaking coolant. I identify this problem, no coolant in the oil, no problems other than overheating and never overheated. I am 1200 miles from home and have to get the dealer to fix it.

They pressure test it and I was right. Huge hole in the gasket. However, they claim that there was a hole in the gasket that allowed somewhere from a cup to a quart of oil into my coolant. Thus, they recommend a convenient $150 coolant flush to remove the contaminated coolant.

#1.Could they have gotten oil into the coolant on their negligence in doing the job right or not taking the proper precautions?

#2.How important is it that I get the coolant flushed? How soon? (I am driving 1200 miles towing a motorcycle this weekend)

I just had my radiator replaced a month ago and all the fluid changed for that. So just wondering if I need to get this done before I drive the 1200 miles home or not…



We have a truck with a problem, and you have to drive 1,200 miles towing a small trailer, is that right?

Oil in the coolant can’t be good. You just put in a new radiator, what will the oil do to that? Can you reschedule your trip? Rent another vehicle? Get the gasket repaired at a shop where you are, rather than drive it home and fix it after 1,200 miles? You are taking chances that what’s left of the gasket will hold up and won’t blow more coolant out during your trip. If the motor overheats it can cause more significant damage, more $$$ to fix.

What’s more important your trip or protecting the investment in your truck?

The upper/lower intake manifold gaskets have no oil ports because there are no components in these areas that need lubrication. So this can’t cause oil contamination in the coolant. Only coolant contamination in the oil.

If there’s indeed oil contamination in the coolant, I would look more towards a leaking transmission fluid cooler in the radiator. Because when an engine overheats, the transmission also overheats along with the tranny fluid. And this can be enough to cause the tranny cooler in the radiator to crack.


The intake manifold gasket is being replaced as we speak (already $650 in). However they mechanics are the ones claiming (I did not see the intake manifold off so I could not see if there was indeed oil leaking into the intake manifold) that oil was leaking into the coolant. My question is really about the coolant flush more than anything. How detrimental can a small amount of oil in the coolant be (ie: less than a quart)?

The radiator was replaced less than 2000 miles ago (in June), and I never actually allowed the truck to get into the red temperaturewise. I have been monitoring the coolant levels because of this problem to keep the temperature under control as much as I could.

You are hitting on what I thought in that I don’t believe there is a way that the intake manifold gasket can fail that would allow oil into the coolant. As far as I understood, you should not be able to get oil into your coolant unless you have cracked a head, blown a head gasket or the oil cooler that is in the radiator failed and allowed fluid to mix.

The coolant may be contaiminated, I’d get new coolant in there.

Exactly! That’s why I question if there’s actually oil in the coolant.