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jvigier 02-08-2010 05:13 PM

Overheating, no heat in cab, 03 Ram 1500
Hi folks, been working on this for a while now and cannot seem to sort this out.

2003 Ram 1500 4.7 2x4

Started overheating with no heat in cab. Top hose into rad is hot but bottom hose is cold. Changed the stat but no luck there, same symptoms (not to mention the old stat worked just fine in a pot of boiling water).

the radiator drains fine from the stop plug, no leaks anywhere, so obviously not clogged.

I just replaced the heater core last year, as well as the water pump, I would imagine neither are the issue.

Here is the strange thing: when slipped off, both hoses (feed and return) to the heater core had hot liquid in them. Yet no heat in the cab...wth???

ONly thing I can think of at this point is to replace the water pump AGAIN...just looking for some feedback, war stories, shoulder to cry on etc...

RamTech 02-08-2010 05:38 PM

The 3.7/4.7 is notorious for trapping air in the cooling system and causing the problem you're describing. Try this - remove the bleeder plug on the water outlet for the upper hose and the radiator cap. Pinch off the upper hose with a pair of vise grips or something similar. Put a small funnel in the bleeder hole and fill with coolant until the system is full and then remove the pinch off and reinstall the plug. Finish topping off the system at the radiator, start it up and see what happens. This method isn't 100% guaranteed but it works most of the time. If you still have air trapped in the system you'll need to find someone with a vacuum venturi tool that can pull the air out of the system. One more thing, are you sure the poppet valve in the stat is pointing up?

bones64 02-08-2010 05:59 PM

Good pint Rem. I have done that before regarding the thermostat. What a piss off to find out that was the culprit after alot of angish.:smiledown:

jvigier 02-08-2010 07:29 PM

Thanks guys, I will definitely try the funnel/bleeder combo Rem suggested!

I will check again on the stat but pretty sure I did that correctly.

I have had to replace MAF, Rad, a/c comp, altntr, both front hubs...too many things to's the thing: weekend before Christmas, with 2 feet of snow in virginia, "tank" got us through even though we were towing a fully loaded trailer...even when the snow plows were getting I guess I have to keep him around.

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