I have a 2001 Jeep Cherokee Classic. I put a new radiator and water pump in and left the thermostat out for a few days. It's still running hot. It don't have a stroud on it. What could be the problem.

 

You do need a thermostat and the fan shroud is important how good is your fan clutch . whit out a thermostat the coolant some times moves to fast though the radiator and does not have time to cool down .

 

x2 on what tech said.

Also you may have the defective 0331 head, so read up on that if you're unaware.

 

agreed... with that year, could also be the 0331 head... but running without a t-stat? Really? pretty easy to see the problem if that's the case.

Just out of curiosity why did you choose to do that?

 

They wanted to flush it out for a couple of days because the water pump fan blades broke off in it. It's back in now.

 

I ran mine for about a week without a thermostat. Could never get it to run over 170° unless stopped for a couple min. Then it would cool right back down once I started moving. I dont think running with no thermostat is the issue.

Jen5Kim - was it the water pump blades that broke off or the mechanical fan blades?

 

I would guess the OP means the impeller blades on the water pump.

I had the impeller break on my 00 TJ when I was 500 miles from home and it was not fun changing the water pump on the side of the road in MD. I will say the state highway folks there were very cool to give me a ride to the parts store and back and help me separate the fan from the fan clutch (the fan's on the pump pulley on that year TJ)..

 

1. Verify you are seeing the correct temp by using a point and shoot laser thermometer pointed directly at the thermostat housing of a HOT engine. It's not impossible that you are seeing incorrect temps at the gauge. Don't want to be chasing your tail.

2. New 195 degree stat. I like the Mopar stat with Stant SuperStat being my runnerup.

3. Haven't seen radiator cap mentioned yet. Replace it.

4. Replace your shroud. They are important.

5. Test/replace your fan clutch. They are important as well.

Basics first. Always.