89 Cherokee help

[GrnMachine]

OK- Tried to do a good deed and buy a car for a single mother I know. She liked old cherokee's, so I found one $2,100. Thought what a steal. Get it home replace serpintine belt, oil, oil filter, plugs, plug wires, air filter. Go to start driving it the 230 miles to her and it overheats. Replace thermostat and even drilled a 1/8in hole in the top to ensure any trapped air could excape. Still does it. Get on this forum and learn what open/closed radiator systems are. Do the conversion, three core open system, also replacing the lines that go back to the heater core and installing a temperature guage. Runs at 220 or so with a slight increase when I stopped. It also stalled maybe once or twice. I made the 230 mile trip without problem. Now about one month later her boyfriend is calling me trying to figure out what I had already done as they are trouble shooting the vehicle. It is now fine when it is cold she drives to school, work, and then the baby sitters. The Jeep can make the first two legs of the trip just fine, but then can need up to an hour break. The story goes that after the Jeep does the first two legs it is getting so hot the the engine feels like it is pre igniting the fuel in the up phase of the compressing stroke causing a very rough feel, loss of acceleration power, and resulting in stall. Once sufficently cooled down (hour or so wait) it will run fine again until it heats back up. I swear no good deed goes unpunished. Please any thoughts. or links to forums that I haven't found yet. Greatfully, Grn

[4x4grey88]

Originally Posted by GrnMachine

OK- Tried to do a good deed and buy a car for a single mother I know. She liked old cherokee's, so I found one $2,100. Thought what a steal. Get it home replace serpintine belt, oil, oil filter, plugs, plug wires, air filter. Go to start driving it the 230 miles to her and it overheats. Replace thermostat and even drilled a 1/8in hole in the top to ensure any trapped air could excape. Still does it. Get on this forum and learn what open/closed radiator systems are. Do the conversion, three core open system, also replacing the lines that go back to the heater core and installing a temperature guage. Runs at 220 or so with a slight increase when I stopped. It also stalled maybe once or twice. I made the 230 mile trip without problem. Now about one month later her boyfriend is calling me trying to figure out what I had already done as they are trouble shooting the vehicle. It is now fine when it is cold she drives to school, work, and then the baby sitters. The Jeep can make the first two legs of the trip just fine, but then can need up to an hour break. The story goes that after the Jeep does the first two legs it is getting so hot the the engine feels like it is pre igniting the fuel in the up phase of the compressing stroke causing a very rough feel, loss of acceleration power, and resulting in stall. Once sufficently cooled down (hour or so wait) it will run fine again until it heats back up. I swear no good deed goes unpunished. Please any thoughts. or links to forums that I haven't found yet. Greatfully, Grn

There are numerous listings on overheating in here.

sometimes the machanical fans quit working correctly even though it is turning. I installed an electric fan to replace the machanical one. Make sure that your aux. fans is also operating.

conduct a radiator flush.

Check it out.

[Dominic240]

waterpump??