manxedout

New here and was reading all of the cooling problem posts and replies, but I was wondering if anyone had looked into somehow reprograming the computer to allow the cooling temp to be lowered and not cause the computer to think that your XJ was still in warm-up mode and run rich? Is there any way to change any of the cooling programed settings? That would allow one to drop the temps, replace the thermostat with a 160-180 degree and help those of us with XJ's that are not used in Alaska.

I live in SoCal and it has been in the 100+degree temps all last week, even with all fans functioning my XJ hates the heat, even when moving on the freeway.

There are radiator changes in the works (CSF three pass) already did the thermostat (stock 190 degree), new hoses, belt, heater by pass, water pump, etc, etc.... but it still runs hot. Coolant level is fine, been burped, oil level is at the mark, all stock 92 XJ with about 80,000 original miles , 4.0, auto, 4X4, A/C. The only thing that is original in the cooling system is the orig 17 year old radiator.

So any one have any idea as to can the onboard program be changed to lower the temp set points for warm-up?

Thanks for all of the info I have learned already, great forum and lots of ideas,

Bob

01LimitedXJ

new radiator will help a lot. fan clutch is good? hood vents would also help you out. hope that helps...

bigomudders

I just learned that once in awhile you have to pressure wash the radiator to get all the mud out looked clean before but damn where did all that mud come from after washing for 30 mins. finally clean 20 degrees cooler.

bigomudders

Here is some good advice the next time anyone goes to a car lot ask for the sales mans home # he will ask why that way you can tell him instead of you calling me I'll call you @ 7 every night until you get one that way you dont have to remember my #

bigomudders

sorry wrong thread pain pills are working

UserID6095

Same here. I cleaned the rad and engine block off and it runs 210* or lower. The underside of the engine, basicly the oil pan and transmission had about ten years worth of dirt and grime under there. Now it looks like new.

Abovetimberline

if your radiator appears to be clear inside,if you can see the tubes,insure they are clear,and make sure the a/c cond and radiator do not have bugs and other items blocking the cooling fins,I take my radiator out so I can get water flow through the fins on the radiator and a/c cond, it looks like you have changed most other items. I am sure it ran cool when new,just need to figure out what is causing it to get hot.

bishop letov

Changing the programming isnt going to fix the immediate problem unfortunately , thats even if you could flash the chip to run out of Warm up. It would require the recalibration of every input that the computer relies on to operate the vehicle.

Had the overheating woes. Changed head gasket... was told it was bad which it was but also found someone put some stop leak in it and there were fibers clogging passages. Removed the rad and opened the end caps ( mine was brass not sure about yours) and the one side of the core was pretty clean but the other had 20 years of residue and silcone from prior tstat/water pump changes. Ran a piece of 1/8 inch cable through each tube and the stuff that was in there was expected. Lots of build up.

Brazed it back together reinstalled and viola... temp came down on average by 15 degrees. just from you telling us that it is still to hot on the freeway points to the rad to me. Mud clogged or internal clog..

I eventually changed to a newer model open type rad with 3 rows and it runs at 195 with a/c going in dead stop traffic on I95 in philly. Got rid of the crappy tank above the heater blower and made more room for a compressor...

fantic238

17 years old? Radiator is clogged.

4.3L XJ

Oe thing you can do is to put in a resistor where the sending unit is. I can't remember what resistance you need, but put it in with a switch to the sending unit so you can switch back and forth. Then it will run right when cold. You could then run a cooler tstat if you wanted. One thing I would do is DITCH that clutch fan. They never have worked all that well. Either run it solid or replace with a high efficiency electric with shroud. Something that pulls in the neighborhood of 2,000 cfm. Vent your hood also. There a number of threads on that subject.

manxedout

Thanks everyone for the other items to look at. The radiator looks clean and clear on the outside, the inside is unknown. This Jeep was used very little (Mom's car) and it spent alot of time sitting in the driveway. It only has 80,000 miles on it in 17 years.

Since the unknown would require radiator replacement I think that will be the next step that makes sense. Also cleaning the engine compartment of any accumulated oil and road dirt. It has never seen dirt in it's 17 years, every mile was on pavement, except one 1 mile dirt driveway up to a residence in NorCal, so call it 2 miles out of 80,000.

The shop that did all of the service through the years has kept it ready to be driven, but I think that the life of the orig. radiator has come to an end. The only other thing that I noticed was that the spring inside the lower radiator hose was missing. I asked the shop that took care of it and they said that the "NEW" hoses did not require one of those, and they pitched it with the old hose. So now watching the lower hose and reving the motor to about 3 grand the hose distorts and tries to flatten. Looks like the "NEW" hoses still need them on a Cherokee XJ.

The dealer does not know if the "NEW" hose has them and want $24.95 prepaid to find out. Napa and other auto parts places said theirs do not
and that you dont need it. So it looks like I make one and add that when I do the new radiator.

Thanks again for the help, and keep your Jeep fingers crossed.

Bob

UserID6095

http://www.redlineoil.com/products_coolant.asp

Problem solved, dang Im good!









j/k.

manxedout

I'm already running a 50-50 mix of water and anti freeze, also has a bottle of water wetter installed when new water & anti freeze mix was added. Still runs Hot!

There is no spring in the lower radiator hose, that will be corrected asap as well as the new CSF 3pass all metal radiator. Gauge is reading very close to my thermocouple temp meter when checked 210on gauge showed as 212 on temp meter so gauge is close...

Doing everything that was mentioned in all of the searched posts on cooling problems....

Is the rubber splash shield that is under the front of my Cherokee required or is it only necessary if I'm fording streams and flooded streets? Is it limiting the removal of the hot air from the engine compartment and radiator?

Thanks for all suggestions and info. still to hot here to take the Cherokee out and not fry it. Will post what happens after the new radiator and spring get installed, so others can get the benefit of my learning curve.

Bob

OnlyInMyXJ22

Honestly, I would swap in a new radiator and leave it alone. Your saying it is running at 212...4.0L's love to run hot. You get best performance out of them at that temp.

warthog

the hose from the dealer does have the spring in it. i ordered one the other day. if you are still unsure about spending the money. call the dealer and tell him to call their parts house to confirm.