I live in south dakota.
this is my first diesel truck.
they don't seem to warm up worth a dang. I drive 10 miles to work and the heater is just starting to get warm when I get there.

Is this just the nature of the diesel motor or do I need a new thermostat?

next questions are where is it on these trucks? how hard to replace?
is is on the upper radiator hose connection like the gas motors?

thank you for your time.

 

The first thing to do is to replace the thermostat. The Cummins ones are very good but the seal sometimes cracks and they leak internally.

I had the same problem and changed the thermostat. World of difference.

Don't expect blistering heat in the winter however. Even on a good day they take a while to warm up and will cool down while idling.

 

10 miles is not long enough for the motor to get warm, unless it takes you 1/2 hour to drive 10 miles.

 

if you plug it in it won't take very long.......when i start out in the morning, i drive in a lower gear until it warms up a bit

 

To replace the thermostat - there is a hose at the front of the motor, it goes from the drivers side to the very front right of the valve cover. (all this is looking @ the engine from the front of the vehicle) The elbow has 3 or 4 bolts in it, remove these bolts, and there is your thermostat. Easy to change. Will probably lose a little coolant when you replace the thermostat so have some extra to put back in.

 

I think before tearing into the engine replacing things, it would be a lot more prudent to do the basics first. Block off the radiator and plug it in for a couple hours before starting.

Not that replacing a t-stat is a big deal, but that shouldn't be the first thing to do when troubleshooting.

 

Not sure why no one asked how cold it is where you live because thats going to make a difference. If your trucks not fully warmed up in 10 miles then the thermostat is bad. I had one go bad on me too and it would not fully warm up in the winter. NAPA sells one that works great if you dont want to look for a Cummins one. Sure its not sub zero temps where I live but its still cold in the winter, and after starting up (not plugged in) and idling about 5 minutes, my gauge is moving in about 2 miles of very easy driving. I only work about 7 miles from home and my engine is easily fully warmed up by the time I'm there. Also, run the heat/defrost setting. The drag of the compressor and the heat of the condenser helps warm it up and will keep the EGT's up slightly while idling.

 

at 4 or 5 miles I feel the cold motor protection turn off on the edge chip.
but not much heat.
at 10 miles it is just starting to put out warm air on the low fan setting.
the temp guage shows around 160 or so.


the truck was full of stop leak when I got it due to a bad water pump.
I had the system cleaned but didn't replace the thermostat.
truck has 200k miles on it so it may just be time.

but sounds like it is not that far off from the normal.

worth a try I guess, I am tired of freezing. I guess I could also try blocking off half the radiator with some thing.

missed that last responce.

temp out side right now is 10 with a 50 mph wind. it is going to get to negative 4 tonight. I keep it plugged in when it is this cold. at home at least. at work there is no where to plug in and it takes a bit for the grid heaters to turn off in the morning.

this last post makes me think it is shot.

thanks for the input.

 

What temp thermostat should one use? I have the same problem with 180k on my truck. It was in the 30's the other day and I could barely get 140-150 out of mine.

 

Are you saying that it wont fully warm up in 10 miles even though you have it plugged in??? Definitely a bad thermostat. And if you opt to cover the radiator then make sure you do it right because there is wrong ways to do it too.

 

I just went down to the local NAPA and bought the one specific for my year. I think it was a 190*. I know that the Cummins thermostat is supposed to flow better that the over the counter parts store ones but I also live where triple digit summer temps are normal and the NAPA thermostat seems to work fine for me.

 

I will go to dodge and get one.
is there a gasket or an O ring?

I don't much care for the stant one's.

cost me a motor in my toyota when it didn't open.
18 dollar part cost me 2000.00. I even tested it before I put it in.


to bad one dosn't think of the heater untill it is to dammn cold to work on the thing!!!

 

Sounds pretty normal to me. You didn't mention how cold it was outside or what kind of driving it was. Does the gauge tick up inside of three or four miles? My drive to work is about twelve miles and I have 6 possible stops (signs and lights) on the way. Average speed is 45 and I don't get any quality heat until I am almost there on a 20 degree morning. Diesels can be pretty cold blooded beasts. Does it run warm, cold, after it is warmed up? I don't think your thermostat is the issue.
Edit: Does it maintain 160 even when running hard? That temp does sound a tad chilly. Is the gauge correct? You mentioned that it was full of stop leak when you got it. Is it possible that the heater core is now all clogged up?

 

this morning it is 15.
I have 4 miles of 45 mph driving, pretty flat road.
maybe see the guage move to the top of the 140 mark.

then 6 miles or so of 60 mph driving.
just about one needle width above the 140 mark.

plugged in all the time when it is this cold.

it warms up fully after about 20 miles.
cools right down if you let it idle.

 

I don't know. At that ambient temp my truck would peak at 200 and ride at about 170-180. Even plugged in, it takes about 7-8 miles to cycle open. Let us know after you replace the thermostat. Smells like I am wrong.