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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My truck won't start and I've already replaced the starter and wiring is correct. 1979 Chevy C10

Hello - your starter problem may be in the ignition switch, or "trigger" side of the wiring. When you turn the ignition switch to the "start" position, is there 12 volts on the "trigger" terminal of the starter solenoid? If...

Q: Reduced engine power warning on, power loss, RPM decrease - 2005 Chevrolet Suburban

It is possible there is an issue in the electronic throttle control system. Faults need to be read out of the engine computer to determine if this is the case. Accelerator pedal position sensor, throttle position sensor, or throttle motor...

Q: Overheating for no apparent reason suddenly and after a longer drive

Hi there. It sounds like you may have a blown head gasket. This is typically the only thing that will allow the engine to overheat that fast. When the gaskets begin to leak, it will allow combustion pressure to enter...

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...