Had a head gasket blow on my 95 Cherokee Sport. Replaced the gasket and had the head machined. It originally blew because of a failed water pump. When putting it back together I replaced the water pump, thermostat, radiator, and temp sensor. According to the gauge it still wants to overheat in about 3-4 minutes. The top radiator how does not get warm, nothing's pumped to the overflow and I can release the pressure in the radiator and feel the coolant, which is still cool.

I can't tell if I have a bad sensor, or need to burp the system more. Any advice would be great.

 

Can you tell if you have any flow,sqeeze the top hose once it gets warm and see if you feel flow,make sure it has enough water in it. what you just described sounds like a blockage,like tstat although you have replaced it,possible it is not opening. A bad sensor will prevent the electric fan from coming on,but you do not even have flow,it sounds,which where your sensor is located it is not even seeing hot water from what you are saying.

 

water doesn't appear to be flowing through top hose. The end into the radiator doesn't even get warm. I know it happens, you replace the thermostat with another bad one. Would it want to overheat so quickly with just a blocked thermo?

 

It seems a bit quick, but if you do not have enough water in the block it can happen,your tstat has to see water temp not heat from the motor to open.

 

I wanted to run it without the thermostat to see if that would fix the cooling problem and hopefully ID the blockage. It did, so I put in a new stat. Everything seems good, except in my opinion the temp reads a little high. If I run the heat, it sits dead center of the gauge at 210. Without heat in SoCal summer, it runs a few degrees hotter, maybe 215-220. Does this sound high? Could it be the new temp sensor reading higher than the old?

 

215-220 is a little high,but it is not overheating anymore right?it is possible a new sensor will change this,or your guage has been off,if it concerns you get direct sensing guage and hook it up,while your at it just get the oil and volts also.

 

If you have a plug on your thermostat housing you can put a guage there which will give you a direct reading. Some housings have no plug to use so you may have to check the local J/Y.

 

So far (2 days now) it's not overheating and its holding very consistent at that temp. I have a switch on the thermostat housing, but it appears to be tied to the electrical fan. If I unplug it, the e-fan kicks on and when I put it back in the e-fan cuts off, unless it's to running temp where it would normally kick on.

This Jeep was given to me by a friend who didn't want to pay someone to do all the work. He was quoted $4,000. I don't have a baseline of where it ran temp wise before the head gasket went out. He couldn't even tell me what model it was, so I don't have much faith in his ability to tell me what the temp reading was.

Fortunately he was very good about getting it serviced. He just put $2,000 in new parts and service; brakes, tires, suspension...

I'd just feel better if it were running around 210, but the price was right so I can't complain.

 

If I am thinking right, the e-fan you are refering too is the a/c fan. If this is the case you should be able to turn it on by putting your a/c on low and it should start working, if it doesnt send pm and ill talk to you about some checks.