Hey guys,

I have had my 04 Dakota 3.7L throw a CEL code P0128 3 times in the last 4-5 months, and I have changed the thermostat twice already. Once I put the new thermostat in, the truck is fine for a few months then it comes back on again.
The truck is running fine, not sure if it is a problem with my PCM or what, but I find it hard to believe that Ive put 2 faulty thermostats in.
I am going to reset my PCM today and see if the CEL comes on again. FIgured I'd see if any of you guys have had a similar problem. Thanks!

 

What's the temp rating on the replacement thermostat?

Lately there have been a lot of crappy parts out there. Have you tried an OEM?

 

To be honest, it was happening this winter so I brought it to a pepboys by my house that I use occasionally when the weather sucks too much to do the work myself. I guess I assume that they used an OEM part, which looking back, was probably my first mistake. The part and labor are still under warranty so I could bring it back but now I'm not sure if thats the right call. Its a 195* tstat, which is what the mechanic recommended.

 

I would change your coolant temp sensor next they are cheap its worth a try.

 

Get a thermostat from your dealer.

 

This winter I had a rad leak so I replaced the radiator, tstat, water pump(which was original), and the fan clutch. After that the truck ran great and temp was always good. Even still, with the CEL on, the truck runs at normal temp (according to the guages), and seems fine.

Thanks for the tip 98Dakaz. I am going to look into it.

Thanks for the help also, 00DakDan. Always appreciated guys.