Heat Problem 2003 6.0L - Diesel Forum

hayes9000 · 12-18-2009, 09:47 PM

My truck can idle for 20 minutes with the heat full blast and only blow cold air. It only blows hot air when I give it fuel, and even then takes a while to kick in. I live in Michigan and it's damn cold out. Any ideas?

Btravelen · 12-18-2009, 11:44 PM

The 6.0's won't blow heat if the coolant level is lowered much.that's the first thing I'd check.

bismic · 12-19-2009, 06:10 AM

Also - If your coolant level is low, look for signs of coolant puking if your level is low (white solids around the degas bottle).

Also again - the 2003 model years had a water pump design weakness. The impellors would crack and come loose from the shaft. The result was "reduced flow" from the water pump.

**teamroper60** · 12-19-2009, 05:15 PM

Quote:

Originally Posted by hayes9000

My truck can idle for 20 minutes with the heat full blast and only blow cold air.

While I agree with the responses listed above, one thing that is being overlooked here is he is apparently expecting it to heat up at idle.. It will not. Diesels don't behave like gassers. They will not heat up at idle.

Get an AIC and ramp up the idle speed to 1200rpms and it will probably roast you (at least mine does).