Overflow 88 Cherokee

[mikeyost]

Hey i had the same problem

I have a 88 Jeep Cherokee and i have done tons of work to this thing. i replaced the water pump about 2 months ago and thermostat about a year ago. i cant quite remember how long ive had this problem but i think ive had it for about a year if not more.

what seems to happen is when i fill the overflow bottle it doesnt seem to take it in. (note that on the older cherokee this is where you fill the radiator, due to no radiator cap. Overflow bottle has a pressurised cap). i just did a rad flush yesterday and the whole system is completely flushed out 100% but then when i would fill the bottle NOTHING! i ttakes like an hour for it to take in like a litre, i tried farting around with it like running the cherokee, reving it up, driving it a bit, but nothing, maybe the rad would take in 200ml but not much as it should.

Please help, i'm stumped on this one

 

[dingus]

RE: Re: RE: Picture please of this!!!

wow i wish i could be of more help, i had a lot of problems with my old cherokee (90 XJ - thermostat, flush, radiator, overflow bottle/cap all replaced) and just replaced the radiator on my new one (94)... as well as the thermostat and a good flush.

my first thought is that the radiator is just REALLY clogged... i'd try disconnecting hoses and shooting a garden hose in there to find out where your clog is... you just gotta cowboy up and get your hands dirty, it wont be fun but there's no amount of guessing that will solve this, it could be anything!

 

[mud4feet]

wow i wish i could be of more help, i had a lot of problems with my old cherokee (90 XJ - thermostat, flush, radiator, overflow bottle/cap all replaced) and just replaced the radiator on my new one (94)... as well as the thermostat and a good flush.

my first thought is that the radiator is just REALLY clogged... i'd try disconnecting hoses and shooting a garden hose in there to find out where your clog is... you just gotta cowboy up and get your hands dirty, it wont be fun but there's no amount of guessing that will solve this, it could be anything!

Don't own a Cherokee, but gotta agree with Dingus. Sounds a whole lot like a clogged radiator. If there's no radiator cap (closed system?), then it should be sucking coolant like a yankee in the desert!!!! Man, I wish I could be more help.

 

[dingus]

Re: lockers on a YJ

yeah that closed system like i had on my old XJ was total crap, i can't believe jeep designed something like that. if i still had my '90, i would have converted it to an open cooling system like the REST of the cars on the road use!

how long does it take her to overheat??? when my radiator needed to be replaced on my '90 i could only run it for about 5 minutes before it would overheat and boil...

 

[lognhornd]

Switching from the old system to the new wouldn't be too hard would it? Unless I am not thinking of something.

 

[dingus]

i can't remember if the old system had a coolant temp sensor in the radiator or not, but the new system does not... other than that, its just a radiator and an overflow bottle swap. not too hard, i wrote up about it on my website, click on my jeep to find it.

 

[CherokeeGuy42]

I might have missed if you have done this or not, but have you tried replacing the hose from the overflow to the radiator, or just shoving something down it and see if something is clogged? If the radiator drained 100% I wouldnt think that it would be where the clog was. I'm not positive or not, but you can atleast try replacing the line or shoving a rod down it or something. My 87 XJ never had that problem. Good luck with it.

 

[MudderChuck]

The heater/surge tank line from the thermostat is pressure. The one going to the water pump is suction. Try blowing in both and see what happens.
When you changed the thermostat, did you use an OEM gasket? If it was a universal type gasket, chances are the heater/surge tank outlet at the thermostat housing is plugged with the gasket.
OEM thermostats have a built in air bleed hole, that helps bleed the air out of the system.
If you remove the temperature gauge sender from the back of the block, it makes fills much easier. It may gyser on you if it´s already filled, don´t try it with the motor hot or running.
Try squeezing the top radiator hose together, with the motor hot and running, this helps move the air out and if you can´t crush the top hose with your hand (it´s like drum tight) this means your radiator is probably plugged or the thermostat isn´t opening.
Most common radiator problems with the closed system, are air trapped in the system, radiator partially plugged, sticky thermostat, surge tank cap frozen shut and fan clutch weak (almost worn out).
The cap on the surge tank, is a pressure release type cap, releases usually around 16 PSI, that´s why it´s recommened to only fill the tank half full. The cap also opens so the system can suck air to equalize if need be. Over tightening the cap, messes with the function, just three finger snug works best.