Running hot randomly after new water pump

[danielmid]

I would tend to agree with your testing and thought process. Parts stores should have the Stant or the Gates in stock, you can drop the temp from the OEM rating as well, like the 190 or even the 180.

 

[Dean2]

Did some troubleshooting this morning. Ive determined that I don't think the thermostat is opening, let me know if you agree.

1. Confirmed no more air in system (best I could).
2. Filled reservoir tank to correct height (it was empty)
3. Let truck idle with radiator cap off and heat on.
4. Truck idled until it reached 206*

At this point the radiator overflowed out of the cap and all over the floor. The top hose measured 160*, the bottom hose was 110* and the thermostat housing was 150*.

This leads me to believe the thermostat is not opening correctly and is also probably getting stuck closed during the times it reaches 221*.

Agree?

Something wrong with these numbers. 1st leave the rad cap on the radiator. The system needs pressure to operate right. If your dash is saying 206 and the thermostat housing is saying 160, what is the temp on the motor side of the thermostat, as in before the water goes through the T-stat. It should be 206 if your truck gauge is correct. If it isn't your sensor or gauge is defective.

If the Thermostat is not opening, then the Radiator should never have overflowed, otherwise where did the overflow coolant come from?

The cooling system in your truck is really pretty simple, it should not be anywhere near this difficult to figure out what is going on.

Simplified picture of how the coolant flows.

 

[Ramrob20]

The radiator cap was off so that any air burped when the thermostat opened. And yes I agree the thermostat did open, hadn’t had enough coffee this morning when I typed that. I guess this thermo just opens a little hotter than the other.

Still don’t know why it’s jumping up to 221* randomly when driving the same routes I always do.

Temps I took just now.

Dash reading:


Top hose:


Bottom hose:


Thermostat:


Water pump:

 

[RedSRT4Me]

The radiator cap was off so that any air burped when the thermostat opened. And yes I agree the thermostat did open, hadn’t had enough coffee this morning when I typed that. I guess this thermo just opens a little hotter than the other.

Still don’t know why it’s jumping up to 221* randomly when driving the same routes I always do.

Temps I took just now.

Dash reading:
View attachment 510239

Top hose:
View attachment 510241

Bottom hose:
View attachment 510242

Thermostat:
View attachment 510245

Water pump:
View attachment 510246

Those temps seem normal with a stock thermostat with + or - in manufacturing tolerance. Likes other suggested you could always get another.

 

[Dodge 1500 4X4]

Bottom hose:

Bottom hose should be allot cooler than 146 degrees, looks like the radiator is clogged!!!

 

[Dean2]

Bottom hose should be allot cooler than 146 degrees, looks like the radiator is clogged!!!

He was sitting still at idle, no air flow. Unless the fan kicks in that reading is about right.

 

[crash68]

Using an infrared thermometer is great for reference purposes but they can be really inaccurate especially when reading through a moving air stream. Couple that with your trying to read through rubber(it's an insulator).
Stick a surface probe on the top of the thermostat housing and/or the metal part of the radiator as close to the upper hose as possible.

 

[Green_Manalishi]

The radiator cap was off so that any air burped when the thermostat opened. And yes I agree the thermostat did open, hadn’t had enough coffee this morning when I typed that. I guess this thermo just opens a little hotter than the other.

Still don’t know why it’s jumping up to 221* randomly when driving the same routes I always do.

You won't properly burp it with the cap off. You need to burp it a the pump. My apologies if you have already done so.

 

[Dodge 1500 4X4]

He was sitting still at idle, no air flow. Unless the fan kicks in that reading is about right.

He wasn't doing it through the air stream of the cooling fan, He still should have got a lower reading using a infrared gun, they are the most accurate, A temp prob who has time to read it!!!, also that heat at idle is the best time to check it, with no cooling going on!!!!

 

[Freakydude]

If the air is out then I would change thermostat. Its going to be your best shot at a simple fix. could be a sensor as well?