Skip the auto shop - Our mechanics make house calls

Q: Van overheats, but only at idle - 2004 GMC Savanna 3500

asked by on

My van is having a problem with overheating when it idles. That is the only time that it overheats - just at idle. I have replaced the following parts: water pump, radiator cap, fan clutch, and the thermostat. One year ago, the head gasket was replaced and it performed in good condition after that replacement, until now. When it overheats, the coolant goes into the reservoir, but then when it is cool again the coolant does not go back into the radiator. I’m thinking this might mean a clogged radiator. But if that’s the case, then it wouldn’t happen at only idle. What is your professional assessment and how to fix it?

A: Hello. Assuming that you replaced the fan c...

Hello. Assuming that you replaced the fan clutch and the fan is actually working, I think you are on the right track as far as the radiator being clogged. When the vehicle is not moving, it does not have the same air flow that it does when the vehicle is moving. Due to the lack of air flow at idle, a clogged radiator would cause the vehicle to overheat.

When the vehicle is moving, the extra airflow passing the radiator might be just enough to prevent the vehicle from overheating even if the radiator is clogged. I would recommend getting the radiator tested for hot spots with a laser thermometer. If any hot spots are found, this would indicate that the radiator is clogged somewhere and the overheating would certainly be cased by this. If any hot spots are found, I would recommend having the radiator replaced by a qualified professional, such as one from YourMechanic. Once the radiator is replaced, the vehicle should no longer overheat.

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: Door won't open from outside.

Anytime I've seen those little clips separated, the doors ended up being broken. The dealership usually has those clips in stock and the hardest part is getting the panel back on afterwards. You can have a certified mechanic, such as...

Q: 1979 GMC Van is overheating

I have a video "How to Fix an Overheating Car". You should watch it because it has to be one of those things that make it overheat. The only other thing it could be is if your catalytic converter is...

Q: Truck won't start -1997 GMC C1500

Hello. The description of the pop and then your car dying makes me check to see if the timing is correct. Distributors will sometimes shear their roll pins and the gear on the end of the distributor will spin. Sometimes...

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.