pfossat

Ok, I've been looking at old forum posts. There are some strong opinions out there about tstats. Will a 180 tstat really run cooler? Some say it won't let the water cool in the rad. Others say it works great. What experience have people had? Has anyone put in the 180 and increased their heating problems?

phsycho

I have a 180 in my jeep and I have had a few time that it overheated. The 4.0 or any inline 6 is bound to run hot. If your stat keeps opening to allow more coolant to flow then as you said it does not have time time to cool in the radiator. Also if your stat is stuck open you will have the same result. Run a 190 and you will get a higher run temp but it will be more consistant.

djb383

A t-stat only controls minimum coolant temp, that's it, nothing more. If ambient temp is cool/mild, coolant temps while using a 180F will be 10-15 degrees less than if using a 195F t-stat. If the heater core is clean and allows good coolant flow, an engine with a 180f t-stat will also have a good/effective heater. This time of year, with high ambient temps, using a 180F vs a 195F makes little to no difference in coolant temps. With summer time temps, coolant temps in the XJ easily reach 210+ (mainly due to the dinky radiator). At 210F both a 180F and 195F t-stats will be wide open. When wide open, they both flow the same amount of coolant. When the t-stat is wide open, the rate of flow is controlled by the water pump and any restrictions (including crud) in the cooling system/passages.

Don't know why any INLINE engine would run hot????? Seems to me both sides of the cylinders on an inline engine are exposed to cool air where as with a V-block engine, the inner portions of the cylinders are buried deep inside the block, much less cooling.

Once the t-stat is out of the picture (open) there's only one source of coolant flow, and that's the water pump. Coolant needs to flow as fast as possible thru the entire system. That's why hi-flow water pumps are available but they will not compensate for a poorly maintained/crudded up cooling system.

TrekkerJmm

I am "Old School" and used to believe I "knew it all about jeeps" so I put a 180 in and it did run a bit cooler but when it got hot it would not cool down at all. I also noticed a drop in gas mileage with the 180 so I went back to a 195 and now it runs cool and my gas mileage is back up...Tj

pfossat

Ok, I'm sticking with the 195. I think I'll wire a manual switch for my aux fan, and install a transmission cooler.