98 Ram 1500 no heat

GM1955 · 12-09-2009, 04:55 PM

I have a 98 Dodge Ram 1500 3.9L that is putting out very little heat. The thermostat has been changed three times. The thermostat is 195F. The heater hoses are warm and about equal temp. I measured the engine temp with an IR thermometer and am getting about 170F and this shows on the temp guage. Does Dodge have a heat problem with this engine?

Chris Stewart · 12-09-2009, 06:51 PM

You might have some air in the cooling system. Others here have "burped" out the air by parking with the front-passenger side much higher than the rear-driver's side, let the engine cool then top off the radiator.

wfrederick · 12-09-2009, 08:14 PM

Reverse the heater hoses by switching them.It works most of the time and cleans the heater core out.

aleekat · 12-10-2009, 06:21 AM

Quote:

Originally Posted by GM1955

I have a 98 Dodge Ram 1500 3.9L that is putting out very little heat. The thermostat has been changed three times. The thermostat is 195F. The heater hoses are warm and about equal temp. I measured the engine temp with an IR thermometer and am getting about 170F and this shows on the temp guage. Does Dodge have a heat problem with this engine?

Back flush the heater core. If you are still running the Dexcool, orange crap. Flush it all out, go back to green. Replace your cap with a Stat.

wfrederick · 12-10-2009, 10:35 AM

That is what reversing the heater hoses at the heater core does,clean the heater core out.Chrysler still used green in 1998 for antifreeze and not dexacool.Changing the heater core is a huge job and the whole dash comes out.Do not flush the cooling system with the machine,it sends the dirt and crud back into the cooling system which is not good.It has been proven any type of flush is not needed and a huge waste of money

GM1955 · 12-10-2009, 04:57 PM

Thanks for the tips but... the heater core has good flow through it. The coolant is green and good. The problem is that the engine is not putting out the heat. Upper rad hose is warm at best, and the lower remains cold. I would normally guess the thermostat is at fault, but how many dealer supplied thermostats do I need to go through before I get a good one?

Chris Stewart · 12-11-2009, 06:53 AM

Was the heat good last year?

GM1955 · 12-11-2009, 10:55 AM

Two years ago. Last year my son was out of town with the truck. I changed the thermostat just before he left and again half way through the winter. I changed it again this week, but same old story. No heat at the rad hoses, little heat at the block.

Chris Stewart · 12-12-2009, 04:36 AM

The gasoline engines in my yard call for 210F thermostats and generally stay close to those temperatures.
I block off about 3/4 of my radiator in the winter to encourage good circulation and keep the temperatures up a little on my truck.

GM1955 · 12-12-2009, 12:26 PM

Where does one find a 210F thermostat? The hottest I can find from either the dealer or aftermarket is 195F. As well, about 90% of the rad is covered. By the time the coolant gets to the lower rad hose, there's not a hint of heat left.

aleekat · 12-12-2009, 05:12 PM

Quote:

Originally Posted by wfrederick

That is what reversing the heater hoses at the heater core does,clean the heater core out.Chrysler still used green in 1998 for antifreeze and not dexacool.Changing the heater core is a huge job and the whole dash comes out.Do not flush the cooling system with the machine,it sends the dirt and crud back into the cooling system which is not good.It has been proven any type of flush is not needed and a huge waste of money

My 96 Ram 1500 came from the factory with dexcool orange.

BleedDodge · 12-24-2009, 06:03 PM

My '97 Ram 1500 still has the original green antifreeze in it, from factory.

truckbro · 07-12-2012, 06:12 PM

could be a broken blend door. I found a kit that repairs the broken blend door problem with no dash removal and takes about an hour. The kit is called the HeaterTreater and they have installation videos on youtube. check it out: www.heatertreater.net

truckbro · 07-12-2012, 06:30 PM

sounds like a broken blend door. I found a blend door repair kit called the Heater Treater that fixes the blend door cheaply and quickly, with dash removal! check it out www.heatertreater.net

GM1955 · 07-14-2012, 09:31 PM

Thanks for all the suggestions. Turn out it was a combination of things. The impeller on the water pump worked it's way forward and buried itself into the housing. It still turned, but would not pump coolant. The overheating, however small because of the massive fan kept the thermostat open and did not allow the engine to overheat. The alumimum from the waterpump housing plugged most of the heater core, but not all. It allowed for some heat and when flushed, appeared to have good flow. The heater core eventually started to leak, forcing the final fix on a long term problem.

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