Question for the Cummins Guys

[DrkMtnDew]

My dad has a 1997 Dodge 12v. Complaint is the heater won't get hot. Thermostat changed. Twice. No Heat. Engine Temp gauge climbs up to 210* and thermostat opens immediatly cooling it off to 160*. The local mechanic told Dad to keep changing the thermostat until he found a good one.

Its in another state so I can't take a look at it.
Whats your thoughts?

[chris142]

Both heater hoses hot? Broken blend door?

[waterboy12]

what brand thermostat are you using?

[DrkMtnDew]

Originally Posted by chris142

Both heater hoses hot? Broken blend door?

From what he's telling me the heater core was replace before he bought it (2 years) and the blend doors seem to be switching. But I will have him double check the heater hoses.

[DrkMtnDew]

Originally Posted by waterboy12

what brand thermostat are you using?

Picked it up a CarQuest. not sure who actuallly makes it.

[Moose-LandTran]

Originally Posted by DrkMtnDew

Engine Temp gauge climbs up to 210* and thermostat opens immediatly cooling it off to 160*.

That sounds like an airlock, temp should reach thermostat opening point, open the stat and it should then remain level at the thermostat opening temp. It shouldn't climb higher, open the stat and then drop and stay level.

[Wackerjr]

Keep swapping tstats.... thats funny... Find a better mechanic for one....

Start with the easy stuff, disconnect the heater hoses and back flush the core first.

Then top off everything and take it for a drive.... make sure it isn't air locked as stated earlier.....

[geologist]

Originally Posted by Moose-LandTran

That sounds like an airlock, temp should reach thermostat opening point, open the stat and it should then remain level at the thermostat opening temp. It shouldn't climb higher, open the stat and then drop and stay level.

I agree. I had this problem as well. On a side note, I had to replace the head gasket on my car. I wasn't finding any coolant in my oil or any oil in my coolant, but I started noticing an oil leak. I tracked it down to the valve cover gasket, replaced it, still had a problem. Checked around the block for leaks, no dice. Pulled the head off and the gasket was destroyed. Did it cause the other problems? Who knows, but once I purged the cooling system and flushed it (after replacing the gasket) I had no problems whatsoever.

[dlenkewich]

I believe water pumps are common issues on 2nd and 3rd gen trucks not producing enough cabin heat.

Also diesels don't produce as much heat as a gasser, almost nil if they are idling.

[Original Man]

Originally Posted by dlenkewich

Also diesels don't produce as much heat as a gasser, almost nil if they are idling.

Really?

[Moose-LandTran]

Originally Posted by Original Man

Really?

Yep. They produce very little heat and it takes a long time for them to warm up.

[ratdoggy]

That's why they use winterfronts in cold weather.

[DrkMtnDew]

This truck even August will not stay at normal temp. Even when Dad has got the horse/house/flatbed trailer on the back. talked to the original owner and he said that truck hasn't had heat or reached operating temp since it was new.

[tonycastec]

Somebody removed the thermostat? T'stat defective and is always open ? Use a cheap I.R. gun and follow the heat along the hoses?

[38Chevy454]

No idea if the Dodge has one, but is there a heater valve that may be not opening fully or plugged up? I would do as some others suggested, use a IR gun and follow the hoses to see what is going on.

[theo2]

Test the T-stat in a pan of hot water on the stove just to see if it opens, try all the simple things first.If you have a thermometer to stick in the pan to check temp. of water when and if the T-stat opens.

[theo2]

Originally Posted by DrkMtnDew

Picked it up a CarQuest. not sure who actuallly makes it.

I know i've tried autozone t-stat in my diesel, no luck. Went to IH and bought t-stat,,,roast you out!

[purplezr2]

Try pack flushing the heater core.

Are you getting good air flow out of the vents. I know after a bit of time, my air flow stops out of the vent creating a low heat condition.

[HOTFR8]

Originally Posted by ratdoggy

That's why they use winterfronts in cold weather.

Originally Posted by DrkMtnDew

This truck even August will not stay at normal temp. Even when Dad has got the horse/house/flatbed trailer on the back. talked to the original owner and he said that truck hasn't had heat or reached operating temp since it was new.

I would try a winterfront but then by what you have added it sounds like a problem the original owner should have had investigated under warranty.

[fury9]

there MIGHT be a vacuum issue,as for the temps going UP and down all the time,perfectly normal. I had a 97 cclb 12v 4x4 for the longest. Heater always worked. Tell him to tab the Killer Dowel Pin with a fender washer (plenty of write ups on dodge diesel cummins forum) That should be his first task. If that pin falls out it could very well possibly KILL the motor