Odd t stat issue

[dlundblad]

I did post this on a Jeep forum, but I imagine anyone here could help diagnose the problem.

If the engine is turned on while warm, the it will run at only about 155*F (10:00 on the gauge.) for quite some time. I'd say 10-15 minutes at least. Also, depending on how long it as been turned off, it'll read slightly below operating temperature and then drop down to 155*F. After playing around with the heater, it does feel cooler when this is happening.

From a cold start, the engine gets to temperature normally and will stay there like it should. Sounds like the t stat likes to stay open at times?

Thanks in advance people of BITOG.

 

[BRZED]

Yes, sounds like the t-stat gets stuck in the open position. Do you notice increased fuel consumption?

 

[Lubener]

Change the stat, they do hang up sometimes.Check codes, some engines will throw a code which would verify low temps. Still acts up? Veifify the actual temp in the radiator, maybe the sender is flaky.. If you have an electric fan, make sure it is running when its supposed to.

 

[dlundblad]

My electric fan has been dead since March and have since upgraded to a mechanical fan.

As far as an increase in fuel consumption, no. But then again, the issue doesnt last too long either.

*Ill check the codes too. Thanks

 

[Drosselmier]

Good time to change the thermostat before winter. Good PM
I had changed one some years ago and the new one went to red line when warming up and then dropped to normal. I changed it once more.

 

[BigD1]

Good thing it is hanging open because closed is bad news as we all know. Yes I would change this part ASAP because there is the chance it could hang closed.

I changed a t-stat on my son's car last winter because he was complaining about a cold heater. It fell apart in my hands when I removed it from the housing.

 

[dlundblad]

I ended up ordering a Mopar thermostat and gasket from RockAuto. Came to about $25 shipped with 2 day shipping so I'd have it for this weekend. Used a code that was posted in the deals forum too.

Silly question, but how do you guys think the oil held up if she was running too rich at times? It only has only been in service for about a week, but it is pretty dark already. I realize color cant be used to judge condition, but it darkened abnormally fast this time.

 

[mk378]

Engine running too cold will contaminate the oil faster than if it were normal. It both runs too rich, leading to fuel dilution, and it never gets hot enough to drive condensed water out.

 

[circuitsmith]

I always replace the 'stat (& radiator cap) every other coolant change.

 

[dlundblad]

I bought a Mopar gasket, but should I used RTV as well?

Thanks for all the input guys.

 

[Nick1994]

Originally Posted By: dlundblad
I bought a Mopar gasket, but should I used RTV as well?

Thanks for all the input guys.
RTV isn't necessary unless it's leaking. I've done a few 4.0L thermostats, piece of cake. You'll know if it's leaking right away.

 

[Lubener]

Originally Posted By: dlundblad
I bought a Mopar gasket, but should I used RTV as well?

Thanks for all the input guys.


I always put a thin layer of permatex 2 on both surfaces of the gasket prior to installation.