Need heed overheating

1990 XJ with the "closed" system water pump is 2yrs old, fan clutch a year old, t-stat a year old. coolant bottle/cap or "turtle" as some prefer is 6 months old ,rad. is 4 years old, started overheating again, blowing coolant out the pressure cap, electric fan is on a manual switch and was in the on position, and heater was on as well, I could not feel coolant running through the bottom hose and it was cool to the touch, Is this a bad radiator or a bad t-stat?

thanks for any help and suggestions

is your upper rad hose hot? this well let you know if your t-stat is oppening. if it stays cool than it is not oppening. if your system is sealed and all compontens are in good condition try giving the rad a flush. iam assuming that the cap is tight and the system is full, with no leaks. good luck.
i have an 89 and was over heating last summer.i had two issues, my tank was cracked so it bubbled over alot. i got a new tank and it still overheated (no bubbles hough) i thought it was the cluch fan but after flushing the rad it came around.

Probably thermostat or trapped air or both.
Did it overheat at idle or slow speed or high speed.
Is the top hose ridgid and swollen? Often a sign of a plugged radiator. Or a collapsed bottom hose. Though with a four year old radiaitor, that is kind of unlikely, unless you´ve been steadily adding some really hard water systematically over the last four years.
I´ve had mine, have a really small leak, near the water pump inlet and had a little air build up in the system and had a series of events follow. Same with a pin hole leak in the radiator.
A little coolant seeps out a leak, during shutdown/cooldown the leak sucks a little air, it builds up in the back of the block and/or near thermostat and/or the top radiator hose. The missing coolant is replaced from the surge tank, the air just keeps building up.
The thermostat with the air bleed hole in the top, works a lot better. Haven´t had a surge tank boil over, after a raditor service, since I switched to that model. Seems to help the air make it´s way to the surge tank quicker, along with crushing the top radiator hose a half dozen times, with your hands, which seems to help pump the air into the surge tank.

Top hose is hot and full of fluid, it's overheated after normal driving, and today it did it at idle in the driveway after trying to burp the system, coolant started coming from the cap and I noticed there wasn't any coolant flowing through the bottom hose.

if theres coolant going into the rad but not out, your pluged. i had good luck removing mine and it only costed 40$ to have it flushed, painted, and pressure checked at our local rad shop.

I think I'll go with a new one. in reflection it might be closer to 6 years of age for the radiator and bad local water, very high in mineral deposits, would this be the time to convert to an open system? or should I stick with what I have.

Thanks,

There is nothing wrong with the closed system and alot of new cars now have them. I just don't like plastic tank and cap. I'd go with one of the aluminum or steel tanks with a normal radiator cap instead of that turtle thing...

i agree theres nothing wrong with the closed system, except for the cap and how the bottle is mounted so close to the hood, thats what took mine out. a new bottle and a little bend in the bracket, good as new. you will have problems with any system if it is not serviced, and parts do fail. our 91 has not had any problems recently, my 89 has but i am not even concidering a conversion. id say stick it out with the closed system.

Could also be the water pump....not to throw another wrench in the works.

BTW there is one huge flaw with the closed system on the cherokees...They trap air. The newer open systems aren't as bad.

When you refill your radiator do yourself a favor and fill with distilled water or second choice rain water (some of you gardeners out there, keep a rain barrel). Distilled water is cheap, when you catch a sale.