Sheff

First off I have been using the search function and google for weeks with no real solution. Since I have had my XJ it has always ran hot. I'm talking about 230 240s. Uphill I'm hitting the white line right before red and having to turn the heater on but I've actually have never overheated. When I'm moving ( not uphill) it stays half way between 210 and red. One day I'm TDY and the wife calls and says I'm leaking coolant everywhere. Turns out the water pump took a crap so I figured I change some other stuff too. As of right now it has a new water pump, radiator, temp sender and the one on the t stat housing that I forgot what it was called, and clutch fan. Turns out the aux fan wasn't coming on either and after much troubleshooting I said screw and wired it to a switch. After all this it's still doing the same thing, maybe a little better. I decided to change the t stat and cap this weekend. The cap was a 13 pound one so I got a 16 like it should be and another 195 stat. The stat I got from napa and when I put that in it wouldn't even open. Went to an O'Rielly's and said screw it and thought I would try 180. I know there suppose to be a 195 and everyone says you shouldn't but it seems that the ones who put them in never actually have a problem. Fuel mileage I couldn't care less about. So I put that one in, flushed the system and it was idling at 210. Sweet right where it should be. It would creep up a little , turn the aux fan on and it would stop it from climbing. Drove around the block and it was fine. So I get in to go to work this morning and it starting going back to the half way point again. My buddy keeps saying air bubbles and I need to burp it. I reply with its a open system and should burp itself. I ran it with the cap off and filled it up slowly squeezing the hoses until it got to temperature and stopped bubbling and then put cap back on. At this point I'm out of ideas besides trying to burp it the closed system way. Maybe putting the 195 back in which I doubt would change anything since it seems like some other problem. It doesn't leak or loose coolant either. A little background, it's a 95 country with I'm guessing a towing package. Has a hitch and trans cooler. Rustys 4.5 lift and 33" wrangler Duratracks HP30 up front Chrysler in the back for now ( 8.8 sitting in the garage waiting for some parts ) automatic. Other than that its essentially stock. Also today while at work I tried to refil, burp it again and on the way home it seemed better driving I'd say around 218ish 220 maybe. It seems like a bubble issue still clogged water jacket or something. I'm all out of ideas besides forking out the money for a 3 row and better water pump but I still feel like IMO just masking something and I should be able to run stock stuff just fine. I'd rather spend my money on that 8.8 in the garage.

Sorry for other story. Just trying to be thorough.

Radi

I think the next thing I'd do is find an IR thermometer, point it at the thermostat housing and see what your actual engine temp is. At least you'll know whether you are chasing an actual cooling problem or a gauge problem.
Anything blocking the radiator like a plugged trans cooler or AC condenser?

Sheff

There's nothing obvious blocking the radiator. I've put a hose to the front to try and clean the bugs and grime off the trans cooler and condenser. My heater works fine but I figured I might flush the heater core too. I've always suspected a temp reading problem. I wanted to try another temp sender because the one I got from NAPA seems not exactly right. It looks like the universal type and really long. Lots of exposed threading even though its tight. I've had bad luck with parts from NAPA.

Kris82

im having the same issue, hopefully someone can chime in

djb383

Have u experimented with temporarily running without a t-stat? Fan shroud intact/in place?

Sheff

Fan shroud was all busted so I replaced that during the radiator replacement. Never ran without a t- stat before. I've heard this is one one to get new coolant thought the engine. Then putting it back in. I'm going to try the closed system method of loosening the temp sender this weekend. I don't have any car ramps so I guess I have to find a decent incline to back up on and let her cool down. I tried to at work by parking on the curb but it needs to be higher. So far this week it's been running 215-220. This is still with a 180 thermostat. I put some hood vents last night so lets see how well they do. Ill make a write up on those eventually.

Pelican

Have you checked temps with an IR thermometer as suggested by Radi?

I went through a very similar scenario several years ago and ultimately added a temp activated unit that turns the fan on at 195* (not necessarily a bad thing in and of itself). I finally got an IR unit and found out that the e-fan wasn't coming on because the engine temperature was never rising to the turn on point -- everything was working just as it should.

May not be your situation but you will never know without verifying what is going on.

A properly functioning open system will self burp through several heat/cool cycles w/o parking on an incline etc. If the burping procedure is required, something else is wrong with the system.

djb383

^^^^^+1

Don't waste your time elevating the rear/removing the sending unit in the back of the head. Never have understood the reasoning behind raising the low part (rear) of the motor. Air in a liquid naturally rises to the high point. Coolant (and air) circulate to the front of the motor (the high point) and thats where coolant (and air) exit the motor.

96 XJ 4.0 Auto

I have a 160* thermostat and the radiator & fans just can't keep up. The radiator is too small in these cars. I even replaced the engine fan with an electric unit that comes on at 160*. Doesn't help much when the weather is warm. When it is hot enough to need the A/C, I have to run the heater not to overheat. What is the biggest aluminum radiator we can fit in these things without cutting things apart?

95Cherokee

You have something wrong that needs to be addressed. I run at 180 all day long and the heat/humidity in Houston is ungodly.

Iven

Same here gauge in dash shows 210, but temp at the neck with an IR thermometer is 163.

djb383

Pretty sure u have drastically reduced air flow thru the rad if u replaced the belt driven fan with a efan.

chuckanut

I've been having heating problems too in my 89 Renix. So today I pulled the radiator out and washed the fins and flushed. It was pretty dang dirty/plugged. Also since my AC doesn't work I pulled the condensor. It also was plugged. This evening my wife and I drove in to town and temp hit 195* tops. True test is tomorrow, supposed to be warm outside.

Sheff

Did you do anything to fix it? I haven't tried a IR thermometer yet but I'm thinking this is the problem. Could it be the temp sender itself? I put a new one in there but it seemed really universal and the sensor part seemed longer. Seems like there a lot of threads showing and the sensor itself bottoming out. I also got a new temp sensor. Could that be it? It wouldn't be the first time I got some crap parts from NAPA.

Iven

Possibly. I ended up putting a new radiator fan sensor in, temp sensor, flushing 3x and soldering in a new gauge. The radiator fan sensor that the parts house was giving me for a 96 Cherokee didn't match my factory plug for it. So I took the one that was originally in it and let them look it put by part number and it turns out its for a Plymouth....lol. With the new gauge I soldered it in to the factory circuit stripes on the back of the instrument panel so I didn't have to cut any wiring. Now I can watch the gauge go to 200 and drop when the thermostat opens up. Better than the previous factory gauge that was reading 260 in and of 5 mins from a cold start. I have set still and hold the rpm at 2 grand for it to even barely go past 200. I'm going to look in to a new radiator fan diode and relay just for a piece of mind. Hope some of this rambling on helps.