Tyheethan

My 2001 has been running at about 185 to 220 for sometime now, unloaded and regardless of where I am-both on the interstate and in town. The outside temp has been around 32* or so.

Yesterday. after driving about 20 miles where it ran in the temp range I mentioned above, I stopped to check the level of the coolant. There was some pressure on the cap but not an extreme amout-it did not spew all over, simply vented the pressure and then I was able to remove the cap-which was not overly hot to the touch.

5 days ago I had the radiator pulled, flow tested, as well as powerwashed for improved airflow as the airflow was somewhat restricted. I had hoped this would help the problem but it really did not do much.

Any ideas?

nitrousn

It should run about dead center on the 190 mark when good and hot when operating at hwy speeds. If you work it such as pulling a trailer i see it climb over the mark a bit maybe 200 or so. I would get a new thermostat from cummins or dodge and do a good flush of the system.

Tyheethan

Has anyone ever had any problems with engine operating at a normal temp but and simply not getting a good reading on stock guages?

RustyJC

My 2002 has run 1 needle width below the 190 mark when empty and 1 needle width above 190 when towing our heavy 5th wheel since it was new - even in ambient temperatures over 100 degF. Have you changed out your thermostat? That's the most likely problem if you've had the radiator cleaned. If you do, get a genuine Cummins stat, not an AutoZone (or other) cheapie!!

Rusty

AggieJustin

Another vote for the thermostat. If you had the radiator checked and cleaned and everything was OK, you shouldn't be getting to 220 unloaded in 32*OAT. I don't even get to 220 loaded running in 100*OAT unless its working REALLY hard.

A common failure with the thermostats is that the supports break and don't allow the thermostat to open fully, so you only get partial flow back to the radiator.

dssimecek

Is the fan running? When my temp gets a little above 190 the fan kicks on. If you hear the fan, Tstat.
good luck

Tyheethan

Going with the T-Stat. I will let you know how it goes.

dieselfan

My fan runs constantly, as soon as i start the truck its on. i thought it was normal, or is it just on 02's?

bamadzl

Last summer I thought my thermostat was bad because I was only getting up to about 160 deg. I replaced the thermostat with a new Cummins thermostat and it didn't change at all. I've since just assumed it was a problem with the sending unit or the gauge. Anyone else had this problem?

Brad

RustyJC

It will run at cold startup until the viscous fluid in the fan clutch warms up. Normally, mine will shut off within a few blocks. If it truly runs at full speed continuously, it sounds like your fan clutch is bad.

Rusty

Tyheethan

Very pleased that changing the thermostat has seemed to work. Temp appears to be steady and just below 190* when up to temp.

I am also glad to find that I do not have a 53 block, but rather one with no numbers.

Lastly, I am also very glad to report that after searching DTR for info on accessing the heater fan, I determined it was very easily accessed and I removed a very annoying leaf caught in the fan squirrel cage that was making a very noticable noise for past 6 months.

Thanks for the help everyone!

Chilidog

I just bought a "new" 2001 and it seems like it takes the truck maybe 20 to 30 minutes to get to 165 or 170 (idling) and both upper and lower hoses are rock hard. Is this normal? I'm trying to troubleshoot a heater issue and wasn't sure if the truck was getting warm enough. Both hoses in and out of heater core seem hot but the radiator hoses don't seem to get too hot. Is this normal?

KATOOM

Welcome to the forum. But its not advised to post new questions in existing threads. Especially one thats over ten years old. Not sure why this forum doesnt close these old threads either...