No heat !!!

[jimmyz32]

2004 F250 diesel 4X4, Ok I changed my degas bottle to the new style. My heads were
Done about 3 months ago so it is not the heads. I am not loosing
Coolant at all. Does not over heat at all. My coolant is Cat ELC coolant
I turn on the heat and the input side of the heater gets hot but the
Output side stays cold unless u get on the skinny pedal a few times
Then it will heat up and stay hot. When driving it only gets Luke warm.
I was wondering if it could be the thermostat or water pump because they are the only things I have not replaced on the truck.
They don't cost much so I am doing them this weekend just want to see if I am in the right direction. Thanks

[jimmyz32]

sorry I don't no why my phone posted it twice?

[twoicebergs]

It could be either of those, but the water pump may have shown other symptoms. The easiest change is obviously the T-stat, if your temp was really low <150. Have you checked the in-line valve on the supply line to see if it works or has all the pieces connected? Fortunately, it really doesn't get cold in Florida, well maybe a few days - it's all relative! Without a lot of fluid going through the core, you have a better chance of corrosion or settlement of debris in the heater core. You could try back-flushing just the core, it may help.

[jimmyz32]

I only use the heater 1 week or so out of the year. The vacume valve works. I will start changing things out this weekend. Thanks