mschi772

Please verify your actual engine temp before assuming your thermostat is the culprit. Thermostats technically only set the minimum operating temp of an engine; likewise, the fans set the maximum (assuming all parts are in proper working order). A 4.0 even with a 160 stat should approach a running temp of 195-210 at which point the fans should stop the temp rise. It COULD be your stat, but I'd rule out a bad sensor and/or gauge first if I was you.

It can allegedly happen to us. Marcus Ohms (gojeep) had this issue with his rig after mods increased his coolant flow too far. http://jeep-xj.info/HowtoRadiatorRestrictor.htm

toasterknight

You are correct that it can happen, but that is a highly modified cooling system. The stock water pump is slow enough that it will not happen.

jopez_89

The reason I'm thinking I have a 160 thermostat is because on start up, my temp will rise and consistently stay at or around 160. If I idle for about ten minutes it will creep about 20 degrees up but drop back down to around 160 when I start driving.

salad

I agree that your gauge should be verified, but it sounds like an open or cold thermostat. That is too much variation.

The rest of the cooling system is designed around an operating temperature in the 195-215 degrees Farenheit range. The thermostat holds temp to a MINIMUM of 195F. Hotter than that the clutch fan pulls more air. Even hotter and the electric fan comes on. Low temp thermostats do not accomplish anything.

Also, closed loop has nothing to do with this. ECT is always considered for the fuel mix. I am not sure what year you have but an OBD-II PCM will set a code if the coolant temp never breaks 180F.

It's a regular wear item - replace it

jopez_89

It's a 2000 jeep Cherokee sport so definitely obd2, with that said I have never gotten a check engine light? My plan is to replace it anyways since I don't know when it was last replaced. If anything arises such as overheating, I'll fix it properly and not just bandaid the problem. The PO did mention something about a loud fan I'm assuming the clutch fan. Makes me wonder if a 160 thermostat was placed purposely to keep the fan from kicking on...

jopez_89

Just replaced the thermostat with a 195 and still doing the same thing. 195 was already in there. Any idea why it's staying so low? I plan on buying a temp gun to verify actual coolant temp soon.

toasterknight

Did you verify the thermostat was functioning before installing it?

mschi772

I'm waiting to hear about the status of the sensors and gauge first.

jopez_89

It was a quality thermostat made in the USA not sone crap from China so I didn't feel the need to. I'll be checking the temp with a gun soon.

toasterknight

No matter where it was made, it can be defective. Always verify, but yes I agree verifying temp is a good next step.

yazd

Just did a radiator flush and put the 160 thermostat and runs a lot cooler plus more performance but who cares if I eat a little more gas and when I have my AC on it stays much cooler it was a little over 200 with the stock thermostat

cruiser54

6.5 year old thread......

yazd

Sorry didn’t realize how old it was but I found this post on the Internet I figured I’d let everyone know the 160 thermostat is just fine to keep your Engine cooler especially when using the air conditioner on load

cruiser54

So, that's not something you've done, but a snippet of someone else's post?

Rogue4x4

Let's see...

Brand new account, check...reviving random old thread, check...posting snippets of other internet posts, check...so tell me, how long before you start spamming links?

I got eyeballs on you. Hopefully it's not what I think it is.Time will tell.