Need help urgently, overheating issues. 2000 XJ

[jaysXJ]

Hey guys. I am in need of some mechanical suggestions. I feel like I've exhausted all of my options and have tried everything to no help. I have scoured all of the forums and have not found a fix. Here we go.

The general gist - My jeep overheats while in traffic or in idle. I have replaced countless parts and have had no success. If I gas my vehicle while in park or neutral and make my mechanical fan spin faster, it cools down to about 220. It has been 90 degrees and up and lately it has been in the 60s in NC, so I thought I had this issue resolved earlier in the week. Specs below.

Radiator replaced, including cap, less than a week old.

Coolant and oil tested, no trace of oil in coolant, no trace of coolant in oil.

Fan clutch replaced, less than a week old. My mechanical fan is intact and gyrates well.

Electric fan/ radiator fan replaced and turns on properly. (1 month ago)(a person who replaced a previous radiator for me when I worked 70+ hours a week did not secure it properly. It fell out of place while driving and was partially destroyed.) I replaced it within this month.

Thermostat replaced and tested, opens correctly, less than a month old.

Water pump replaced, less than a week old. The old one seems to have been functioning properly, but it is staying in the Jeep for good.

I have replaced the Crankshaft Position Sensor less than a week old(unrelated, cranking issues)

My fan shroud for my mechanical fan is intact.

I've checked the hoses for blockages and have found none.

I've lost so much coolant at this point, I can't even suspect "old coolant." Regardless, I flushed the radiator and motor through the thermostat opening.

My oil was changed less than a week ago to check for traces of coolant.

Once the thermostat opens and the electric fan turns on, I can FEEL coolant surging through my upper and lower radiator hoses.


***There are two key, possibly vital bits of information that I have deducted.
1. I did not have any overheating issues before my electric fan was replaced. The one that I had in the Jeep which was the original did not cause my engine to overheat. The original was much heavier. The new one provided by Advanced Autoparts is about 2-3 pounds lighter. The material in the original Jeep fan was a heavy plastic, almost resembling metal. The one I received is clearly lighter and is made of plastic(or whatever the hell they're made of) I experienced no substantial overheating issues before I replaced my electric fan which was then in pieces. HOWEVER, when my original electric fan was in place, it would run CONSTANTLY. At this point, I feel like a temporary fix would be to return my electric fan and pick one up from the junkyard. Thankfully, the electric fans are extremely easy to replace.


2. The ONLY hose that I saw something that might possibly be a clue, the heater core hose, when disconnected, discharged a dark fluid. This is my next course of action.

I've put so much money into this vehicle, and well. I don't even want to go there.

I need some feedback. I do not have another vehicle that I can drive and Charlotte traffic is horrible on my way back from work. Today I sat in traffic for far too long unable to do anything about my Jeep's temperature being high.

If I seem ungrateful or rude please forgive me. I am at the end of the line with these issues and could have purchased another vehicle with the funds I've used to "fix" this jeep.
Thank you for your time.

:bang::bang::bang::bang::bang::bang::bang::bang:

[bluedragon436]

Well first off I would say hit up the PNP and snag a factory electric fan, just for shits and giggles and see if it helps with that begin the only change made.. If so, then one I would def take the other one back just to get that money back.. and two I would try and have your compression checked for each cylinder.. I would say flush your complete coolant system too, including the heater core.. When I did the water pump on mine, the coolant passages that I could see behind the water pump had all kinds of gunk in them, so I put the hose in there and flushed as much as I could out that way, then I flushed and back flushed my heater core quite a few times and between doing that stuff it def helped get my heat level back down some on my 98.. But being as how you have the 00-01 problem child years as far as the heads, I know you said there was no look of mixing between coolant and oil, but never hurts to get that checked anyways as far as the compression, especially the rear cylinders... I had a friend who had somethign similar going on with his 01, and was just about to junk it save the money he had already spent on it trying to figure out the issue, and after doing a compression check one late night after I got off work and drove to his place... we found that both rear cylinders were fairly low, so we pulled the head and found out that the head gasket between the rear cylinders was shot, so it was allowing coolant to drop onto the top of the pistons and was being burned off, and was causing the coolant to stay even warmer then usual due to the obvious higher amount of heat coming straight to it from the combustion chamber.. so figure it's worth a try, and shouldn't cost too much if you don't have the tool to do it yourself.. You can also pick up a tool from Harbor Freight or even rent it @ AZ or another auto parts store...

[XJ Wheeler]

First thing, do you know if the gauge is correct?

Sent via messenger pigeon - i talk, he types.

[Brasscatz]

I'd go with the electric fan from the junk yard, then bypass your heater core and see if that cures it. Also, is your A/C running? The condenser in front of your radiator might need replacing as well.

[4.3LXJ]

There is a possible issue with the fan. The late fans would move more air than the early ones. About 300 cfm I think, which is about 10% gain over the total amount. If you have gunk in the hose, I would suggest you flush the system. You could have a lot of buildup of rust and minerals previous to this that will affect heat transfer. Also, the heater hose acts as a sort of bypass for the water pump. Circulating the coolant through it will help with keeping an even temp.

[jaysXJ]

Well, guys. This has been a learning experience for me, I'll say. I believe the issue is resolved. I almost don't want to share because it's far too simple of a fix, but I feel like I should just in case any other people have the same issue as I did.

Today, my mother being the lovely woman that she is, offered to take my vehicle to her backyard mechanic while I drove a spare to work. It had already been looked at by two ASE mech's and other backyard mechanics. By the time she got over to her friend's house, my jeep was sitting right outside of the "orange" zone. The guy let the vehicle cool down and waited until the vehicle heated up again to the temperature at which the fan turns on(219 I think.) He noticed my fan spun in the wrong direction, pulling heat towards my motor. The fan was mounted properly(I don't think there's a way to mount them incorrectly.)


APPARENTLY the plug for my electric fan was turned BACKWARDS. This might have been a simple fix for me if I had taken the split second before the fan moves too fast to note its direction. There is no indication as to which pin goes in the top and which goes in the bottom on the fan I purchased. I honestly did not know that was even possible. Another indication would've been for me to check if I felt air moving at the grill from the fan.

Today I drove my car home 35+ minutes in 80~ weather and idled it for 20 minutes when I got home. The gauge sat perfectly at 210, as it always had with the electric fan only turning on briefly.

Now let's hope no substantial damage was done to my motor. I plan to drive my Jeep for a long time.

I want to thank all of you who offered good advice. I'll still work on the heat core as preventive maintenance.

One last note, I had already removed all rust from all coolant passages. The difference in my case, was minimal.

[4.3LXJ]

I have to admit, I would not have thought of that sitting here. That is one you have to be there to see

[Brasscatz]

hmm. Did not see that one coming lol. Hey! Free and easy fixes are the best kinds!

[jaysXJ]

"free" in a way, lol.
I'm big on preventive maintenance, so at least I know I won't need any of those parts soon.

[XJ Wheeler]

That is a surprise. I know the older XJs have a connector that makes it impossible to get it connected backwards. Glad it was simple!

[bluedragon436]

That is awesome.. Hope it is the issue, and you are good to go again... I would say that if I were you, I would have just selected my new mechanic to hit up...

[autotech98]

gotta love those multiple model fans.replaced mine with a four seasons and it had an adapter plug that went between pigtail on fan and factory pigtail.almost did the same thing.:headbag: