Got in my truck this morning, 1995 D3500 12valve engine, It was about 2-5 degrees outside, and what always seems to be a slow heat up, on my way to work, never happened today. I froze all the way to work (45 Minute Drive), but the engine did warm up according to the gauge, in the normal distance/time as always, normal operating range - not high or low. Any ideas to keep me from freezing, other than dressing warmer?

 

check your anti frezze. if it is low, at your temp should be 50/50. heaters and external hoses ect will freeze before block. If heater and hoses freeze it takes fore ever to thaw if it does not break.(no circulation)
Clark

 

Wow, even if my truck heater was plugged in all night and working, the other lines could still freeze up, I guess I didn't realize that. I do keep my fluids checked on a regular basis, so the low fluid would also surprize me, unless I have recently developed a leak. I will check it out. Thanks

 

Not low fluid level, low coolant mixture( not enough antifreeze to water)
Clark

 

Check your heat controls on the dash. It moves a door in the heater box and controls how much air goes thru the heater core and how much bypasses it, and that is how it controls the temp inside the cab. An easy way to see if the coolant is flowing thru the core is to hold the heater hoses between the eng and firewall to see if they are hot. If one is hot and the other is cold then you have low flow(plugged core), If both are hot then the problem is under the dash.

 

Did you feel the heater hose at the heater plenum after you stopped to see if you had hot water going to the heater?