I changed my water pump today, pretty straight forward job I thought until
I went for a test drive and the temp climbed up to 200.
Checked under the hood, hot engine and cold rad.

I assume I have a failed thermostat, anybody have the
Cummins replacement thermostat part number?

Thanks

 

Here's the number from the sticky. Cummins Part# 3802968, there is also a write up in there to glance over.

 

Are you sure you have all the air out of the system? An air bubble will do the same thing.

 

I'll try loosening the plug on the housing and see if any air burps out
before I order the stat.

 

Try taking plug loose at top of cylinder head the small plug. Open radiator cap and fill radiator untill coolant comes out threw plug hole. Then install plug ( put a little teflon tape or sealer on threads). Fill radiator and overflow bottle with 50% mixture.

 

just checking did you put fluid in the rad, its not enough to just putting it in the over flow bottle, just checking, you dont know how many people think thats all it needs

9 times out of 10 its air in the system, grab a fender and shake the truck around, put it on a bit of a hill and open up the screw to let the air out

 

I went to work on the truck this morning and found that the cooling system
had burped the trapped air out overnight.

It had sucked the overflow dry, and I had to add another gallon
to the rad and refill the overflow.
That was some burp! (2 gallons worth)

I test drove it and everything is OK now.
Hopefully I didn't hurt anything when it got hot yesterday.

 

If the head gasket didn't blow you are OK. 200 isn't that hot.

 

I haven't wrenched on cummins much yet, but whenever I changed a t-stat on a gasser, I would drill a 1/8" hole in the t-stat flange for the single purpose of letting air through while the stat was closed. The tiny bit of h2o that passed never seemed to make much difference.