I live in az were its waaay hot out and I recently got a Cherokee, I drove it for about 15mins today and the second I rolled in the driveway it overheated and antifreeze went every where and some white smoke came out, I let it cool down and it was okay. This was with the ac on also. And right after I started it up and let it run sitting there with ac on and it was fine right at about 220 were it holds. I couldn't find any cracks in the radiator either, and the e-fan comes on with the ac as well.

I opened up the thermostat housing to find no thermostat, I got a 180 an am going to put it in, will it make a difference Having one? What other things should I look into? Or get? Any help is appreciated.

 

Should have a 195 degree t-stat, but the 180 is better than having no t-stat at all.

 

Yeah that's what I figured. Even though it didn't have t-stat it still overheated waay to fast.

 

I hope this helps it out having a tstat. Because it over heated really quick (15mins). Any more input is appreciated.

 

Thats because the coolant just keeps passing through the engine block.

With a tstat it closes and lets the coolant cool down in the radiator, when the engine gets past the temp of the tstat it opens and cools the engine.

Not using a thermostat is for someone who is trying to make it around the block to work because they have huge problems overheating.

I'm put in a Mr.Gasket 180F on my other profile on CT I have pictures of three different thermostats; stock, better than stock, and the best IMO.

 

The previous owner most likely removed the thermostat to try to mask/hide the root cause of the overheating. (bad idea)

What year XJ do you have? Hope it isn't an 00-01, as they came from the factory with the 0331 cylinder head, which almost assuredly will crack upon an engine overheat.

Find the root cause of your overheat ASAP. Lots of things in play here; water pump..........radiator...........belt.........radi ator cap.......fan clutch.

 

The Thermostat & Overheating Issue seems like the most common in this forum. May be the onset of hotter weather.
If you have imeadiate overheating I don't think it was due to a lack of a thermostat, although I agree you should have one.
Is your 1/2 water 1/2 anti freeze mixture correct?
Is it full? Are your belts OK? Water Pump circulating?(my #1 guess of your problem)

Hopfully it is not a cracked head. Does you oil seem watered down?

I did a thorough flush of mine recently, a straight six 99 with the drain plug in the left side of the block. To get out the drain plug I sacrificed an old 3/8" short extension and made a tool to fit in the square plug opening by using a bench grinder and taking a little off all 4 sides. To guage my grinding I used a 5/16" open end wrench and kept trying it on both sides untill it fit over the end of the extension. I will attempt adding photos

 

I want to add, Be generous with the PB Blaster and soak the area of the plug. Northern Jeeps Especially.

 

clean the radiator (exterior) with a water hose. is is amazing what will come out of it even if it looks clean from the front. i guess i mean the a/c radiator in front of the radiator. be careful if you use a power washer, the fins bend very easily.

 

....or u can buy 5/16" bar stock at a hardware store.

 

A properly functioning t-stat does 1 thing....control minimum temp. If the t-stat is functioning correctly OR there's no t-stat and it overheats, the overheat cause lies elsewhere. At overheat temps, the t-stat is wide open, thus performing like no t-stat.

 

Crap ok, I have a 99. Ill check the water pump.

 

What do u know about it.....PO's maintenance? If u know nothing about it, presume nothing was done.....it's been driven like it's stolen and now overheats. The XJ's rad is pathetically small, every cooling system component must be top notch, especially this time of year and your location. +/-$250 in parts does the complete cooling system including rad. If u do it all at once, u only have to drain/re-fill cooling system once.

 

Good point, yeah the PO sucked at maintenance, so im prob screwed. Ill go threw it all and swap parts out. Hopefully nothing bad.

 

Just so you know the tstats main purpose to "control the temp"

If any of you ever been to a water park where they have that pool with a current that goes around the park or in a big patern or circle?

That water is flowing constant and when the people **** in there and its a hot day the water stays warm.

Until the the park "closes", the water will stop flowing and get a chance to cool down.

Now think of your cooling system in that way, Then tell me that it doesnt matter to have a tstat installed. "constant flowing boiling water"

Would you go into that "pool"? Imagine what your engine is thinking. LOL