Engine/Transmission (1998.5 - 2002) Coolant Temps above 200

[RJWEST]

After about 5 miles of driving , I noticed my coolant temps were running about 210 degrees ( needle to the right of center), stayed there for about another 3 miles, than dropped back to normal. Outside temperature was about 75deg.



Is this normal, or is a new thermostat in order, 63k miles on truck,

doubt coolant has been changed. . Do coolant/thermostat ?



Any recomendations, on either/both...

 

[georgej]

While 210 degrees may ok for the thermostat to open I would go ahead and do the antifreeze-t stat change just to be sure and rest easy

 

[blacksheepdiesel]

RJWEST,

Carefully pressure wash the engine side of the radiator, it is likely coated with oil which attracts dirt which keeps the rad from cooling properly. I actually pulled my radiator out and washed both sides, put it back in, problem solved.

If you do put a t-stat in only buy Cummins, the others just don't seem to work correctly.

Godspeed,
Trent

 

[RJWEST]

Thanks, is it a 195 and does anyone have the cummins PN,

Got rid of the oil vent bottle, washed the back side,
Probably a good idea to check radiator,

 

[jkidd]

ditto on the radiator being plugged up. could not see through mine, I removed it and relocated the breather bottle. I was stuck going 30mph up a hill because my coolant temps were too high. not any more... .

 

[Graphic man]

I agree..... pull the rad and clean it..... it's easy to pull should only take you about 10 min

 

[Boondocker]

The factory engine temp gauge isn't a precision instrument. Starting with a cold engine (thermostat closed), as it warms up, it is normal for the temp to go past the "normal" point then drop back down. This means your thermostat opened. It's a good little sanity check really.



If your crankcase breather bottle is in the stock location, expect a dirty radiator. Be gentle when you clean it, doesn't take much pressure to bend the fins.

 

[RustyJC]

After about 5 miles of driving , I noticed my coolant temps were running about 210 degrees ( needle to the right of center), stayed there for about another 3 miles, than dropped back to normal.

The fact that it stayed up, then dropped back sounds like a sticking thermostat to me. If the radiator were plugged up and load/speed didn't change, there would be no reason for the temperature to drop.



Rusty

 

[RJWEST]

OK checked the temp gage real close, cycles from ? 1/3 below center mark
to slightly over center mark, Only seems to do this when outside temps
are at least 75 degrees,
Not normal???? Cummins PN anyone...

 

[blacksheepdiesel]

Yep, you need a new Cummins t-stat. You can log on to Cummins QuickServe Online with your ESN and find any part # for your engine. Sometimes it is much easier doing it that way than having the dealer try to figure it out.

www.quickserve.cummins.com

You will have to create an account first.

Godpseed,
Trent

 

[RJWEST]

thanks !!!!

 

[Jengle]

Mine has done that since new. Only when it first warms up, it will go a little above 200, then come back down, and hold steady. I just put a new 195 thermostat in, and it does the same thing, too. Radiator is clean. I take it to mean this is normal for this truck.

 

[rotohead]

I just did a coolant/t-stat servicing and I found the little round flat plate of the Cummins t-stat that seats down to stop coolant flow... I found it broken off the main t-stat and wedged in a top coolant passage. Normally it's attached to the t-stat with just a rivet type connection. I looked around and found the best replacement at NAPA. It is re-designed and looks like a 1/2" brass plug that is much more durable looking. Just what I found and thought I would pass it along.

Chuck