Heater not working unless driving(warm air at a stop), coolant level right at the max line, upper radiator hose is only warm to the touch and the lower radiator hose is cold to the touch with the engine up to operating temp (after a 30 min drive) and I can squeeze the hoses very easily. Its about 35f - 40f degrees outside. The hot water valve but the oil fill tube is opening and closing and the vacuum line is hooked up. Wasn't to sure where the heater core is in the glove box but I reached my hand up around the top of a box that resembles a fuse box cover and what ever I touched was to hot to keep my hand on it. Any ideas? 04 6.0 with 110k miles heads, head gaskets, oil cooler, turbo and arp studs done by ford under warranty at 95k miles. EGR welded shut. Thanks for any ideas and hope its not the head gaskets again!
If it were my truck I would flush the cooling system with Restore (both directions on the heater) and change the thermostat. The restore removes the silicate deposits left by Ford's gold coolant, refill with a HD truck coolant like Rotella ELC. My '04 makes nice heat in the 20's in two miles of driving, and my EGR cooler is deleted as well.
usually thermostats stick/fail-safe OPEN - requiring longer warm up times -
if the thermostat is stuck CLOSED you over heat (lack of cool water circulation).
you dont say the year or mileage of your truck so im guessing when i say it could
be a water pump.
you could also have air trapped in the system preventing coolant flow....have
you recently drained or flushed the system ?
what happens when you <SLOWLY & CAREFULLY> open the degas cap (do you
hear pressure let off) ??
flushing isnt a bad idea but if the system is plugged enough youll like have to remove
the radiator and have it rodded and cleaned by a radiator shop - if the radiator
is plugged up that bad you could also have issue w/ the oil cooler and the heater
core also plugged.
changing the coolant will not affect this problem - you've got a coolant flow issue.
It's in there at the end, "04 with 110k miles". Yes I hear a pressure release when I open the cap. Last time radiator was flushed was on the head stud job about 16 months ago.
if you just had the oil cooler replaced, i wouldnt do the coolant flush.most likely just a stuck open thermostat, especially if you say the lower hose is cold. just my opinion
My t-stat dosen't open at all lately, truck averages a coolant temp of 168-172 degrees, lower radiator hose is ice cold after any length of driving. I can hammer the throttle at full boost and never see above 172. I probably should put a radiator blocker in to help heat things up. I forgot to mention, it's been in the low teens today and around 3 tonight. I found my t-stat won't open until it gets in the mid 40's. My heat works fine and fairly quickly. These trucks have a huge cooling system, and with egr deleted, its even harder to warm the t-stat up enough in cold weather. You may actually have a clogged heater core though, thats just my opinion. And don't put green coolant in, when 69cj said simple green, he meant the simple green cleaning soap to flush out your cooling system with. Only the gold or elc coolants have the proper cavitation protection you need for the 6.0 diesel engine. Good luck.
EJ Krueger,
Im having the same problem. What is it that fixed the issue?
Thanks
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