I'm completely baffled. I have a 2015 with the 3.6 and was getting the P0128 code, so I went ahead and replaced the thermostat with one I got from Mopar (part #05184651AJ. Anyhow, I replaced it, burped it, etc. but I noticed the temp is only hitting 185 and staying there and the code came back after about 3 days which I can only assume is because it's too cool? Anyone have any suggestions on what I'm missing?
Thermostat is baffling me
- Thread starter hicarbon
- Start date
Well, the likelihood of having a failed open t-stat (you can also check the one your removed too for verification) - AND having a failed brand-new t-state is incredibly, near statistical impossibility. Do you have good heat inside the Jeep? That would be a good indication that your engine is hitting the proper temp.
Sounds like your temp sensor is likely the culprit... Do you have JScan and a dongle by chance?
Sounds like your temp sensor is likely the culprit... Do you have JScan and a dongle by chance?
Yea I can't imagine it would be two bad t-stats either and I was really hoping it wouldn't be the sensor (I really don't want to deal with the frustration of replacing that lol). I don't have the old one anymore unfortunately, I replaced it about a month and a half ago. The heat inside isn't quite as hot as it was before but it's not just "warm" either if that makes sense. I do have JScan, but it's only showing the P0128
You should be able to go into JScan and check the monitors. On a cold engine, the ambient temp sensor and ECT sensor should show essentially the same temperature. Once running, you should be able to see the temps rise gradually under idle, and faster under load. It should also show you when your fans are kicking on (been a while since I've been in the monitors) and you can verify that the temps (and fan activity) are acting normally.
Been there, done this.
The best, easiest and quickest way to check your t-stat and make sure it's opening at the proper temp, or if it's stuck open:
1. Cold start the engine. Have someone do it for you, as you will be standing in front of the radiator with one hand wrapped around the upper radiator hose.
2. If you immediately feel water flow through the upper hose upon start, the t-stat is stuck open.
3. If you do not feel water flow thru the upper hose immediately upon cold start, while keeping an eye on your coolant temp PID on JScan, ascertain what the temp is when you do feel the coolant flow.
The best, easiest and quickest way to check your t-stat and make sure it's opening at the proper temp, or if it's stuck open:
1. Cold start the engine. Have someone do it for you, as you will be standing in front of the radiator with one hand wrapped around the upper radiator hose.
2. If you immediately feel water flow through the upper hose upon start, the t-stat is stuck open.
3. If you do not feel water flow thru the upper hose immediately upon cold start, while keeping an eye on your coolant temp PID on JScan, ascertain what the temp is when you do feel the coolant flow.
If the heat isn't as warm as it should be you might still have some trapped air in the system. When you bled the system did you jack the front of the Jeep up about 6" with the radiator cap off and engine idling?
No unfortunately I didn't. I also noticed this afternoon when I started it I could hear what sounded like water running right behind the dash which I've been told before could mean there's an air pocket. I'm gonna get the front end up, pull the radiator cap off and see if there's still an air pocket.
Typically, with air remaining in the cooling loop, the temp gauge will bounce all over, going hot, cooling off, etc.
When you get the front end up and open the rad, add coolant a little at a time and force the air out. Add coolant to the cap level. The rad will "burp" the air as it's forced out of the cooling loop.
When you get the front end up and open the rad, add coolant a little at a time and force the air out. Add coolant to the cap level. The rad will "burp" the air as it's forced out of the cooling loop.