Hey guys....my first post about the new to me 2001 dodge ram 2500 truck. I have never owned a diesel pickup before...all prior trucks have been gas. My only experience with diesels are the motorhome I have and even that I don't know much about.

I purchased the truck in Florida approx. one week ago and drove 1300 miles to Chicago to get it home. Ran great except one issue I learned about. While in the 94 degree weather in Florida the engine temp seemed fine in the 180 degree range. As I got further north the temp was falling until it never got over the 140 degree mark when I got into 40-50 outside temps. When I tried to run the interior heat it was barely warm air blowing out the vents.

I am wondering if maybe I have a thermostat stuck open?

Thanks much,
Phil
obtw....I averaged approx 22mpg on the trip....which I was pretty pleased with

 

I think you're right on the money. Sounds like the thermostat is stuck open to me.

 

Id have to say your right, id get a new thermostat and see what that does

Sent from my HTC Evo

 

Also,

 

yea ivote stuck thermo... whats the temp do at idle... if its stuck open should heat up alot!

 

If its stuck open, it wont heat up hardly at all because its allowing coolant to constantly flow and not heat up. Now if it was stuck closed, it would.

To OP, t-stats are about the easy things to replace on an engine, right on top and relatively cheap. I'd start there

 

thermostat is open for sure

 

When at idle nothing changes...temp stays low....which is what I would think should happen if thermostat is stuck open.

Thanks guys. I know in the past I have had issues with thermostats being stuck open or closed but those were gas trucks. I kinda figured the diesels were pretty much same but have no history and wondered if maybe they just ran cooler by nature.

I will get a thermostat and replace and see if it fixes the problem. I suspected with the truck spending it's life in Florida the thermostat stayed open more than closed.

Thanks,
Phil

 

Yea thats a cummins problem, we've had several T-stats do the same thing, the disk that seals against the seat will warp and let water through, some flow a little and some alot.

When you get it out, dry it off good and I bet you can see light through it.

 

Just to update....I replaced the thermostat with new and all is fine now. Can't see any physical problems with the old one but it does have two little holes that are plugged by what looks to be ball bearings. When I took the housing cover off to remove the old t-stat antifreeze came flowing out the two little holes which tell me there was always fluid flowing which would not let the engine heat up.

The new t-stat does not have the two little holes/ball bearings....I never saw a t-stat like the old one before.

O'well....I'm just glad it was a simple fix.

Thanks for the feedback,
Phil