1988 Jeep Overheating

[ballanceg]

1075846

I have read many posts about this problem before. I have a 1988 Jeep Cherokee Limited with 160,000+ miles on the original motor. I love my jeep except for the constant overheating problem. I've had the problem for about 3 years. I finally discovered the radiator was going bad - holes and rust so it was replaced 4 months ago. Drove fine for a while and then I lost the recovery tank cap and purchased another one from our local Jeep dealership. Never fit right and overheating started again since pressurization could not occur. In the past, I've had the water pump replaced once (2 years ago) and the thermostat replaced twice (last year or so most recently).

Yesterday, I had the recovery tank replaced with a new tank and cap. Drove it home - about 20 minute drive and overheated again. Actually, the gauge didn't show overheating, it was still s howing just under 210 degrees. Someone behind me noticed the coolant leaking a block from home. I opened the hood while still running and it was overflowing from the recovery tank again. Cap still on tight.

Turned it off and loosened the cap and finally took it off. Spilled in the driveway as usual and then quite bubbling. You could hear it from inside the jeep with the engine off - the bubbling from the recovery tank as it oveheated.

Any ideas are greatly appreciated. New Radiator - new recovery tank - I've been told to replace the thermostat again with a 185 degree thermostat this time and if that didn't work, try the water pump. I'm tired of guessing. Help!![addsig]

 

[Utah_jeepster]

1075850

You still have two things to replace yet...lol one part is cheap.. and the other a bit more exspensive and I would recomend you start there.. sorry about that.
With a new radiator and pump your still not getting the cooling.. that would suggest that your fan clutch is going. The 20 minutes you stated and the motor started to over heat is the key. The fan clutch is slowly loosing is grip and not spinning as fast to draw the air across the radiator. With warmer weather this problems is starting to show up. Replace the fan clutch and see if that fixes your problem.
Last you over heated and your gage didnt go over 210... anti-freeze doesnt boil over till over 250+... also look into replacing your temp senson as well.[addsig]

 

[MudderChuck]

1075874

Something I´ve had a lot of trouble with during and after radiator service is, air in the system.
A small leak will often run the fluid level in the resivoir or surge tank (whatever it´s called)too low. When the motor cools down again, it will suck air into the system. Also during refill, it´s common to get some air trapped in there.
Air sits in the high spots, top radiator hose, above the opening of the thermostat and sometimes the surge/heater lines. You´d think the flow of coolant would force the air out, it happens, but most often, very slowly. The air often acts like a partial blockage of the coolant flow.
There have been many tips, like parking on a steep hill and reving the engine, to get the air moving. I´ve had the best results, squeezing the top radiator hose flat (four hands work better than two). then after running it for awhile, repeat the proceedure, on consecutive days. Really takes awhile to get rid of all the air.
The OEM replacement thermostat has an extra built in ball check valve, which helps moving the air around the thermostat (so actual coolant and not air temp) is actuating the thermostat.
Something that is always suspect, with a cronic overheating problem, is a head gasket. Head gasket failure is rare in the inline six, but happens on occasion. The hot gases escaping into the cooling system, will mess things up, in numerous ways (air blockage) the high temp. of the gases themselves etc. With the cap removed rom the resivoir, start and run a cold motor, until it warms up and watch for surging of the coolant (some is normal) and also for foam or bubbles. Constant unexplained loss of coolant (not due to leaks), miss firing motor and some drops of coolant (colored not clear) from the exhaust are also indicators. Some condensation out fo the exhaust is normal.
Overheating at idle is often air in the system, fan clutch weak or auxilliary fan not coming on line. Overeheating at highway speeds, is often bottom radiator hose spring (too short, missing). Partially plugged radiatior, mud, dust or whatever on the outside. Or air trapped in the system. Head gasket passing hot gas into coolant system.
These are some of the less obvious problems. The surge tank, works best when half full. A severly out of tune motor can cause overheating, as can a paritally plugged exhaust system.
Hope I´ve helped with a few ideas.

edited by: MudderChuck, Jul 12, 2003 - 08:02 PM[addsig]

 

[woody-wagon]

1075979

Try this website http://www.off-road.com/jeep/cherokee/98/06_jun/cooling/cooling1.html It has cooling upgrades to make your engine run cooler.

Matt[addsig]

 

[jeeperscreepers]

1076046

I hope you find a solution soon. I have a 89 commanche truck w/ the inline 6 (4L)that has been doing the same thing. It has a new radiator water pump thermostat fan clutch and the heads have been taken off and checked for leaks cracks etc. One we found out on my truck was that the water and coolant wasn't going through the radiator at all instead it went straight into the recovery tank and boiled steamed out. IF you figure out what was wrong write me an email at. davisoetken@hotmail.com
GOOD LUCK[addsig]