Q: 1979 GMC Van is overheating

asked by on

We drive a '79 GMC Van and it's heating up like crazy. We had recent oil changes, transmission serviced, radiator flushed. We had the radiator cap changed, thermostat checked and all the fluid levels are good. Any idea what could be bad?

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 clogged up. It will make the engine overheat but for that you can get it tested. Any good mechanic can place pressure gauges on before and after to test and see if there’s a bunch of pressure before the catalytic converter, like 8 or 10 PSI, and if there is hardly any after. If so, the catalytic converter is clogged up causing the car to overheat.

As I mentioned before, try all of the tests in my video. It’s got to be one of those issues or a clogged catalytic converter. Also, I’d recommend having a certified mechanic take a look at your car to diagnose and fix your overheating problem if it persists.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. 1979 GMC Van is overheating

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

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...

Q: Window controls not functioning properly.

This is most likely the result of a failed power window motor or regulator. The regulator is a scissor-type lift that moves the window up and down when powered by the motor. A professional, such as one form YourMechanic, can...

Q: The Check Engine light blinks and the car stalls. Is this my catalytic converter?

This may be related to many different things such as a bad oxygen sensor (this monitors the activity of the catalytic converter), a bad or dirty idle air control valve, or potentially low fuel pressure. The low fuel pressure will...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...