Overheating Diagnosis [1989 Jeep Comanche 4.0L I6]

[james-mc]

I havent had much time to work on the ol jeep this week. Work has us doing OT. But I think I'm going to replace the pump and hoses. Pump wobbles and the hoses are old. Might as well change them now before it leaves me stranded in the future. Parts are about $70-80 total. 

[james-mc]

Well today I managed to change the water pump (and brake booster while I was at it).

Old water pump was rusty but still pretty solid. I didnt toss it as it still seemed to work. I went ahead and changed it anyways. I kept the old one and cleaned it up just in case I ever need it.

 

The problem was bad Reservoir cap and an air bubble at the water pump.

I filled the reservoir first. Then I filled the rad from the upper hose. I also removed the plug on the t-stat housing and filled from there with a small engine funnel. I let it run while with the cap loose and heat on high. Tightened it up and took her for a drive (about 2 miles). It didnt overheat so far. It sat around the 200-210 range. Now on to the new door lock cylinders.