rdub25

I have a 2004 f-250 super duty 6 liter diesel and I have been having some problems with the heater. The problem is that the only time that it gets warm is when I am going down the road at 70 mph. When I slow down for a stop light etc... the heater goes cold again. My temperature is running right in the middle of the guage which seems normal to me. I thought about getting a grill cover but it doesn't seem like that would fix the problem. Anyone have any ideas?

360ci

Have you had a coolant flush and fill performed? If not, it'd be a wise choice as it will remove any contaminants. Heater cores will rust out over time, blocking the coolant from flowing properly. This would explain why you get heat when traveling on the highway. There are also kits one can purchase where you can backflush the heater core with a standard garden hose - it's just not the right weather outside to do that.

__________________
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!