Hi y'all,

My '02 Dodge Ram 1500 (4.7L V8) is overheating while idling or driving slowly in traffic. It will redline, the check guages light comes on, and it starts spewing coolant. But at speed, it cools down and is just fine.

I've replaced the t-stat and the radiator cap, hoping one of those would solve the problem... no luck.

Any ideas? Or do I need to call a more mechanically inclined friend?

Thanks!

 

Overheating at Idle and low speed?

1. Is your fan working? If the clutch is not engaging, the only way your truck will get adequate airflow through the radiator is by travelling at higher speeds which would be a perfect explanation as to your issue.

2. When was the last time you flushed your cooling system?

3. Have you checked the coolant with a coolant tester to see what the boiling point is? An improper ratio of water to coolant to can cause it boil over much sooner then it should.

4. Is your radiator original? If so, what does the interior look like? It could be heavily fouled with mineral deposits and/or corroision.

 

When was the last time the coolant was changed? If recently, was it "burped" properly? Maybe have some air pockets in there.

 

Overheating at idle means your fan clutch is likely not working. Redlining a 4.7 and getting it to the point that it spews coolant means that you either have head or head gasket issues in your future if not already.

 

Also try taking a garden hose to the radiator fins to clear them out of bugs and road grime.

 

With those symptoms, it 'bout has to be the fan clutch. If you can turn the fan with the motor hot, the clutch has lost its grip on the water pump shaft.