I purchased a 96 cherokee awhile back and found out later it wasn't the original motor, a myriad of problems have occurred. I've had my mechanic replace almost the entire cooling system the head gasket has been replaced and after its recent return all seemed much better, I was still getting to 220 but it was getting me to work and back. 2 weeks later it's at it again from what I can only assume is more debris breaking off in the cooling system. My mechanic said i can't do an acid flush because my freezer plugs have rust on them and this would cause leaks relatively soon. So my question is what steps would you take? Is there anything I can do to reduce the temps further, it has a 180 Tstat already.

 

You need to start by letting use know what has and hasn't been changed out???

 

I've replaced the water pump head gasket radiator and hoses. The mechanic mentioned that the catalytic converter may be clogged.

 

I would definatly change the thermostat. Also if there is alot of build up in the cooling system an acid flush may be necessary which means you may need to replace the freeze plugs. If the build up breaks loose it will continue to plug up your t-stat and radiator.

 

You need to think about changing the T-Stat and the recommended temp is 195. Also make sure that the elect fan is coming on. Check you fan clutch and radiator cap. One last thing is to make sure that your fan shroud is in place end not missing chunks out of it.

 

They replaced both t stats within the last couple of months, and I put in a new shroud recently. I guess my question is will back flushing alone without an additive clear out the rust if done on a routine basis?

 

Does electric fan come on ? Is fan clutch in proper operating condition ? Is the coolant staying clean or getting rust colored again ? iIf freeze plugs are in need of replaceing do them .

 

Good questions. Also consider replacing your coolant temp sensor, or at least cleaning and re-seating the connector, and checking the integrity of those connector wires. If you are getting bad data, you are chasing a ghost.

 

One simple way to check the cat is with a vacuum gauge. If it's bad enough the vehicle won't accelerate, lol. Inlet/outlet temps could be checked too.
The cooling issue- do you keep getting crud in the coolant after flushing? Checked the actual coolant temp with an IR thermometer?