So I've recently acquired another XJ on a trade, it's a 96 4.0, 5 speed and was someone's turbo project. It runs great except for if I get the Jeep up to temp, it'll stay somewhere close to 210 while driving, but as soon as I let it idle after it's up to temp it starts to get hot pretty quickly. The jeep has a new water pump, new radiator, an efan that is wired to the ignition which replaced the clutch fan, I put in a new thermostat yesterday, and did a coolant flush, oh and brand new head gasket as well. Probably pretty important to add that this issue is new, I had no temp issues until one of my rubber coolant lines cracked causing me to lose all coolant and go up to about 250. Ever since I replaced that line, it's a constant battle to get it to stay at a good temp when I'm not driving. And another thing I've noticed is if I park and immediately turn it off when the needle says 210, the temp will climb 20ish degrees AFTER shutting off and then cool down pretty quickly. Don't know where to go from here, any help is much appreciated.

 

Might need to flush and bleed your cooling system, if it lost coolant and you replaced a hose, likely there is air in the system. Also go back to the mech fan paired with the stock efan. Most efans cant move enough air when the car is moving slow.
The temperature always heats up when the car is off and parked. No air or coolant circulating through the system

 

Many junk new thermostats being sold. Id replace the thermostat first. You may need to buy 3 or 4 to get one that works correctly

 

Tried bleeding again today, did the spilless funnel method. Stayed around 210 for a bit while I let the bubbles come out and when I shut it off I guess it was hotter than it said because the coolant all boiled out. And my issue with the stock mech fan is there's not enough room with the intercooler, the radiator is moved back to fit it which leaves no room for the mech fan. This is gonna be a fun issue to fix because sounds like I'm going to have to relocate stuff :/

 

This is already the 3rd new one, and to be honest I don't think there was anything wrong with the first few, but I've been told that thermostats are made pretty poorly so I've tried a few different brands to see if it made any difference, which it didn't. Tried running no thermostat for ****s and giggles and absolutely 0 difference.

 

Put them in boiling water to visually see if they work or not.

 

Buy Mopar thermostats only FWIW. Pricey but worth it.

 

Stock dash gauges don't read correctly, at operating temperature mine is off by 10'

 

The Efans are your problem, none of them pull as much air as the clutch fan. Put the factory fan setup and a good shroud on it and your problem will most likely go away.

 

I'd have done that with the old one, to see if it needed replacing.

I doubt if there ever was such a thing as a Mopar stat. certainly not after 20+ years. (just a generic one bought in from the cheapest source, put in a Mopar box & priced accordingly).

You could cut out the middleman & get one one from whoever Mopar does (did?) but, personally I've always bought things like 'stats of a leading brand of that component. That said, I've never had to replace a Jeep 'stat, although I think the '97 XJ got one when we did the HG, so it probably came from the local wholesaler, who supplied the gaskets.

 

As re-instating the mech. fan appears not to be an option, is there room for a 2nd e-fan? (that's what everyone seemed to be doing 10years ago, when I got my 1st XJ). Failing that, the option is to go the Taurus/Crown Vic/Volvo route.

 

I agree. The cummins guys used to swear by only cummins tstats but they seem to be hit and miss now. I currently have a tstat in my jeep that runs to cold. Like max of 150deg unless im idling in 100 deg heat for a long time.
I dont think it closes allowing fluid to come up to temp before cycling through system.

 

You would need at least 3 e fans and they still wouldn't flow as much air as the mechanical fan, and with the engine being turboed it will produce even more heat.

 

There is indeed a Mopar stat!!

It functions like no other knock off or generic stat.

 

hey Cruiser, see my thermostat question in the "stock" forum?