I used heat Monday worked fine, tried it tonight (Sunday) and nothing. I did a search. I have no heat at idle or during acceleration. I added about a half gallon of anti freeze about a month ago when I noticed it was low. It's only about 50 degrees out also, and the temp gauge is in the normal range. When I got home I checked the overflow tank, it was fine. I was able to open the cap with no overflow though and just a minor hiss. Upper hose is warm, not hot same as the radiator. My ride home was only 20 minutes but that should be plenty of time to get to operating temp. My truck is bone stock (until I pay it off) I ran it for a bit without the cap on and it never overflowed, it moved about half an inch when I gave it throttle. This truck is my first diesel, I've had it almost two years and the only major issue I've had was a high pressure oil pump in July, that was tough to swallow but I just paid that off. Any ideas on where I should start? Thanks in advance for any help...

 

Is the blower switch working ? (fan speed). Can you change between different locations (defrost ,floor vents,dash vents,etc?) You can empty your glovebox push the sides in to tip it down . Right behind it is the heater core. You should be able to reach in and feel if it the lines going in and out are warm.

 

All the controls fan speeds etc work fine I'll check behind the glove box tomorrow, but the radiator itself doesn't seem warm enough... I can touch the aluminum top tank without burning my hand.

 

I don't have a powerstroke so I'm not sure how quick your radiator should warm up. I'm in the middle of fixing a blend door issue on my 2007 v10.

 

Interesting update, made the hour and and a half commute in stop and go traffic this morning with no heat, 37 degrees out when I left When I got there I could touch the radiator I even opened the overflow tank and touched the fluid, it was hot but didn't burn meI could leave my finger in it for as long as I liked. Two hours after I got there and parked it when I left for my next stop, I had heat.... have had it all day ever since until I got home at 10:30 PM....

As the day progressed, everytime I stopped I would pop the hood and try to touch the radiator, it was way to hot to touch, Thermostat? Blockage? Ideas? From what I can read and see it looks like diesel cooling systems have some major differences from what I am used to