Overheating Grand Cherokee

jeep
grand-cherokee

#1

I have a 95’ Grand Cherokee, V8 5.2L. Recently, it started overheating and was diagnosed as a head gasket issue at a shop. I ended up replacing the head gasket, thermostat, and water pump. (The radiator, top radiator hose, and radiator cap were replaced within the last year as well.) Despite the repairs, the coolant in the reservoir does not move. The Jeep overheats and there is a squealing noise coming from what may be the water pump. There is also a slight leakage of coolant near the water pump bypass hose, but does not seem to be coming from the hose itself. What else am I missing?


#2

Bring it back to the shop that did the work.
The shop needs to check that the correct pump was used, it’s turning the right way, and that the radiator hoses aren’t collapsed inside and are flowing freely. Radiator hoses are made in layers, and the inner lining can separate from the outer sheath. They also need to diagnose where the leak is coming from, as this will prevent the system from maintaining the pressure it needs to allow the coolant to go to normal operating temperature.


#3

One of the steps when replacing the water pump on your engine is, Spin the water pump by hand to ensure the water pump impeller does not rub against the timing chain cover.

Tester


#4

Hand spinning the water pump before installing the drive belt as part of the install is always a good idea as mentioned above. I’ve never had a problem with the impeller hitting the cover, but I have had noises from the water pump occur when working on the cooling system. What happens I think is that stuff, calcium deposits probably, gets dislodged in the process and it can lodge in the pump and make a racket. I’ve had to remove the pump and clean it out one time to get rid of the noise. And stuff stuck in the pump could make it spin slower, and could cause overheating. I think you may be looking at having your shop remove and inspect the pump again.


#5

If the cooling system is very low you will have to refill the radiator, the reservoir won’t refill the system. Get the leak repaired asap, if you over heat the engine you could damage the head gaskets (again) and cylinder heads. If there is coolant on the serpentine belt the belt will squeal, doubtful the wrong water pump was installed, how could it leave the shop with a seized water pump?


#6

I actually do all the work on my Jeep myself so I can ensure it’s done properly, but I had the original head gasket issue diagnosed at a shop before I dove into the project.

The radiator was filled with coolant at the time that the water pump was replaced. I also followed the directions in the service manual closely, making sure to spin the pump and make sure the impeller does not hit the timing chain cover. The pump worked properly and the impeller did not hit anything. I will check the integrity of the bypass hose and others to make sure they are sound. The top radiator hose is new and inflates properly when the thermostat opens up.


#7

I am not sure what you mean by that statement. The hose should not inflate.


#8

Do you mean the level in the overflow tank never changes, no matter if the engine is hot or cool? For that I’d suspect first a thermostat problem. One idea for a test, that top radiator hose that seems to be filling up when the thermostat opens, remove it from the radiator and see how much water is actually flowing in that hose. Once the stat opens there should be a robust stream, on the order of turning on the garden hose full force. I’ve had new thermostats fail right out of the box, so that’s a definite possibility.
It’s also pretty easy to install the thermostat w/the wrong orientation too.