Engine/Transmission (1998.5 - 2002) First introduction and operating temp question

[AHuska]

Hello TDR!



I've been a member for most of the past year now, but I've just been soaking up information as I hunted for the perfect truck. Well it finally arrived! It's pretty much the nicest 90,000 mile truck I've ever seen and should serve me well for years in my hobbies of hauling classic cars, 4x4s, and the occasional tractor.



So on the drive home, about 60 miles @ 60mph, I was studying all of the gauges with good numbers all around I think (transmission 140*, fuel 14psi with not much drop at WOT, engine oil 155*) except for coolant temp (150* MAX). Even on the longest hills I couldn't get that needle above 155, and it wouldn't waste anytime going lower when I was sitting in the drive-thru. I read that 180-190 is normal, with the stat opening around 170ish. Ambient was around 45*F and cooling off toward the end of the drive. I'm assuming the thermostat needs replacing, but since this is my first diesel of any kind I just thought I'd ask for confirmation. Is it possible that 60mph (less than 2000 rpm) isn't enough to stay warm in the cool weather? The vents were blowing warm enough that I had to turn down the mixer controls.

 

[johncameron]

You are correct, you should see ~180 within 15-20 miles easy at that outside temp. The thermostat is easy to change.
John

 

[Joe Mc]

Yep, sounds like the T-Stat. Make sure you get a good one, not a POS from the local auto parts places. I'm guessing NAPA would have a quality unit probably STANT manufacturer. Make sure when you install it the air bleeder valve is on top.



180-190 normal operating temp. Mine gets there on a 7 mile ride to work.