i have an 89 cherokee can't seem to stop it from over heating when not on highway. replaced waterpump,radiator,thermostat,and heater core.

Bud them old vehicles have scared lots of guys.. Does it actually puke it's coolant out or does it just SHOW hot on the guage? Give us a blow by blow on the temperature.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

it has the pressurized tank which i replaced and it is puking the fluid out.

head gasket, air in the system, could be a few things.. no water in the crankcase?

He says "not on the hiway" Which leaves me to think the fan clutch ain't working.. The radiator ain't getting enough air until the speed increases.

So check the fan clutch.. If a head gasket is suspected there are two methods to use to check a leak out.
1. Pull the sparks and look at each one for rust..
2. Most evffective is to fill the coolant tank and start the engine let her run for a while and continue to refill the tank as the coolant completely fills the engine..
Then while running watch the level of the coolant closely looking for small bubbles. Yes the bubbles will always be there if the head gasket is leaking. They will be very small...yet visible..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

there is no water in crank case. i just went and bought a new clutch fan so i'll try that thanks