PONCHO130

I recently purchased a 1999 XJ and noticed that the temperature would rise over 210 when when going at slow slow speeds at the ranch. When I would travel on open highway at speeds over 30 mph, temperatures were below 210. I took the radiator cap off and noticed it had water instead of coolant. Today I took the bottom and top hose off the radiator and ran water through the water neck and the radiator. Water on both sides came out a little brown but then clean. Then I filled it up with coolant. Now my engine will overheat quick all the way to the red even while I drive. What could be the problem? Need help before I reall screw it up!

BlueRidgeMark

Air pockets are a good possibility. Find a place where you can put the driver side wheel up on something like a curb (or a car ramp if you have one) and run the engine til warm enough to open the t-stat. Pop the radiator cap and watch it for a while. Add fluid as needed.

Another possibility is that you broke some crud loose and it's blocking something. If burping it doesn't help, do a thorough flush.

smoker9000

I agree, it could need burped, also could be a bad clutch on the fan.

djb383

The so-called burping process will go a lot simpler if u let the motor idle with the rad cap off and keep the rad full while the motor warms up. Once the stat opens and coolant starts to flow out the top of the rad, install a new rad cap. Check fluid level motor cold for next several days and add coolant to rad and/or bottle as needed. Some of us have had success doing this on level ground.....no jacks, ramps or curbs.

RTorrez1

This is how I have always bled the air out of the cooling system on all of my XJ's and never had a problem.
Also when you you said "I filled it up with coolant". You didn't run straight coolant did you? Hopefully you meant you put 50% coolant and 50% water? When you flushed the radiator did you also flush the engine block until the water was coming out clear? Also like smoker9000 it can be your fan clutch. It is a very common symptom for a vehicle to over heat at lower speeds when the fan clutch is going out.

PONCHO130

I did check the fan clutch and it appears to be good. The only thing I had was straight Coolant but added water to it. I did flush the motor as well. Neither the radiator not the engine were that bad. I did let it idle till water came out then added cap. Runs a little better. Bout to take it on a bit longer trip to test it out. Keep y'all up to date. Thanks.

JackJare9455

you might want to start "considering" a complete cooling system overhaul... since the weak part of our jeeps IS the cooling system...

Its relatively cheap for our jeeps, and RockAuto has everything you need...

After I did mine, it cools great...

RTorrez1

Just don't take to long of a test run. Just saying, You don't want to over heat it and cause real damage and leave you stranded. Good luck and hope that it runs cooler. Let us know.

PONCHO130

I took that longer trip and ran a lot cooler than before. I'm considering a new radiator, water pump, thermostat, an electric fans. Thanks guys!

RTorrez1

Just curious, What kind of temp are you seeing now? Yeah, A complete cooling system over haul is a wise move and can be done for around $200-$250. Since you have a 99 all the parts can be found at you local parts store. The one thing that I would get OEM is your t-stat that should be 195deg. One last thing if you go with only elect fans and get rid of the mechanical fan. Do yourself a big favor and make sure that the elect fan puts out enough SCFM (Standard Cubic Feet per Minute). Most of the fans that you get at the auto parts store do not put out enough flow to keep it running cool like it should. To get a good quality fan that also puts out the correct SCFM are not cheap.

djb383

The fan clutch gradually degrades in performance with time/miles. What appears to be good may perform less efficiently than a new. Unless u know how old the fan clutch is, spendy the $35 for a new one.....then u know u r back to peak performance. Heed RTorrez1's advice.....do your home work regarding an "all efan setup". The OE stock rad fan set-up is not the weak link in the XJ cooling system......it's that dinky radiator. Do your home work when selecting a replacement rad and don't. Advertising/marketing hype talking about "multiple rows" is usually just that....hype. Consider core thickness, number of tubes vertically and fins/inch. Bigger numbers (except for number of rows) are better. For the past 20+ years rads have been constructed of aluminum and plastic mainly because of better efficiency.

smoker9000

just my 2 cents, but don't go cheap on any part of the cooling system, I just put my third "life time warranty" water pump in, on my second radiator, and the big box parts stores can never seem to find my warranty info in thier computer, so keep the receipts.

AZSnake98

Have you noticed any drop in the coolant level/needed to add coolant?

Roler

I agree with the cooling system overhaul. A new to you vehicle with overheating issues= tackle it before you do more damage.
The viscous fan is a tricky one: it can look great, test fine, and still be under par (mine stood all the tests, but it was not until I replaced it at last, that my temps went back to the good side of mid-scale).
And as mentioned, for you guys the $$ involved are reasonable. Investing in cooling system is money well spent.

RandyQuickXJ

Has anyone ever used any heavy duty fan clutches before...I got one through orieleys or how ever you spell it and it seems like its junk to me you can never hear it working only when you first start it if its cold and start driving right away you can hear the fan actually working but other than that i never hear it but i agree with all of these guys, ive done about 5 of my friends complete overhaul on there cooling systems and its a very good thing to do...did it on mine also