Engine/Transmission (1994 - 1998) -5*F and heater won't work

[brewer]

My heater won't work when it gets real cold. It was plugged in all night. The heater will work when temps are around 20*F and up.



Anyone have this problem or know what might be causing it? Or how to fix it?



Thanks...

 

[JoeBioDiesel]

When you say the heater doesn't work, What do you mean exactly?

It blows air, but it's just not warm?

What is your engine temp? Normal?

what is the temps coming out of the vent? I know mine will only blow 110F when it gets too far below 0F. I know that sounds hot... but it's not for a heater.

Joe

 

[LostTrucker]

I would check your antifreeze 68-32 h20:-laf I would also check your engine's operating temp while driving 180-200 degrees, if its cooler than that, its possible that your thermostat is sticking open. This is kinda common and I would only buy a genuine cummins thermostat, I have had bad luck with after market ones

 

[EKlem]

If you are getting heat when it is warmer but not when it is really cold and everything else seems to be working, it is possible that you need to block your radiator. These engines are relatively thermally efficient and when it gets cold, the radiator is actually too large for an unloaded engine and the coolant can't get hot enough to give you heat. If I don't block most of the radiator in my truck when it gets sub zero, I don't get any heat. Try putting a piece of cardboard right in front of the radiator that covers most of it and see whether it makes a differece.

 

[LHastings]

If you are talking about your block heater. I don't think there is thermostat in it . Sometime the cord goes bad at the plug. You may have a break in the cord. Get you a ohm meter and ohm it out. Also check the connection on the block for corrosion.

 

[brewer]

Thanks, I'll try blocking the radiator. Everything else works fine. It blows air, but it feels like the temp that it is outside. What does check your anti-freeze 68-32h20 mean? Is that the ratio of anti-freeze to water? Thanks again...