Skip the auto shop - Our mechanics make house calls

Q: Cooling system issue - 1999 Chevrolet C3500

asked by on

Several months ago, I did some repairs on the truck by myself. I had the radiator replaced. I installed a new lower intake manifold as well as new gaskets. It was all fine. The only issue I had at the time was loss of coolant. Now when I drive it, the truck is running fine and has no trouble starting. However, I had the oil checked and it turned into sludge and I found there is coolant in it. The radiator is full of this now. I thought that it's defective. It is spitting oil and is full of bubbles. I filled the cooling system with air but to no avail. Did I do the repairs badly and caused this or is it something else causing this? Do you have any advice what I should do now?

A: The lower intake manifold gasket you replac...

The lower intake manifold gasket you replaced seals both coolant, and oil passages. It is possible that coolant (under higher pressure) is leaking into an oil passage. It is also possible you have a bad head gasket - leaking coolant into an oil passage when you shut the truck off hot. A professional mechanic, like YourMechanic can help isolate this issue and address the possible coolant leakage you may be having.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Starting problem, engine revs at low RPM in drive - 1999 Chevrolet C3500

It sounds like the Idle Air Control valve is gunked up. It may be possible to clean it, or it might have to be replaced. A YourMechanic professional can help to diagnose the stalling issue and replace the idle air...

Q: ac compressor goes bad for the second time and burns out

It sounds like you have more problems than a compressor. Did you flush out the A/C system, replace the orfice tube, replace the accumulator, add oil before replacing the compressor, and then evacuate and recharge the system? If this was...

Q: Gasket or main seal leaking oil.

There are dozens of places where oil leaks can originate. The rear main seal and head gasket are just two of the possibilities. I suggest you have dye put in the oil system to determine where the leak is coming...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...