thing is I have barely any heat. Was out a few nights ago, and it was around 15F. I was pretty cold in the car. It was barely lukewarm air. So I'm thinking stuck open thermostat possibly?

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1990 300D 2.5
1991 F350 7.3 Dually IDI

1997 F350 gasser dump
1980 H-D 93 inch Shovel
2000 SE Roadglide