S-90 2001 2.9 L non-turbo. MY original problem was an engine overheating problem under running load. I have replaced the thermostat and the radiator, but problem still exists. Has anyone seen this problem where the water pump was the problem? This pump only has 33K miles on it. I'm assuming that the pump impeller is spinning freely on the shaft.

Also, can anyone tell how to flush the heater core out? Does the engine have to be running for the coolant flow to the heater? Or can I hook a water hose up to one side of one of the heater hoses and flush through?

Any help would be appreciated

Mark

 

Is the cooling fan working?

Yes you can just connect a hose and flush it.

 

Yes the electric radiator cooling fan is working

 

I would look at the water pump next.

 

Water pump is on the UPS truck and will be here on Thursday. The simptoms are that the car will warm up tp normal temperature, and then the coolant level will slowly build up in the expansion tank until it completlet fills the tank (from 1/2 full to start) then the engine temperature will rise from that point until it hits the overheating range if I let it. Everyone I have talked to about thois on the internet says water pump, and that remains to be seen.

Any thoughts on a head gasket leak into one of the cylinders? No codes show up..

 

I would also do a compression test.
Maybe have a block test done as well to check the headgasket.

 

Yep. What would be the problem here. I am also into this question. I also conducted a compression test but I don't get that much info after that.

 

I did a compression test and found all 6 cylinders at about 180 psi. That led me to the water pump which by the way only had 33,000 miles on it. it turned out that the GEBA water pump that was put on the car with the last timing belt change out has a plastic impeller and the plastic impeller cam eloos from teh shaft. The pump shaft has a splinned end and the female end on the plastic impeller came loose in my opinion due to differential expansion between teh metal shaft and the plastic impeller.

You will have to take the timing belt off to get teh pump off. One mistake I made was not lioning up the timing marks on the top two cams first and marking the bottom crank in place. The water pump is driven off of the timing belt. You will also have to take the 4 bolts loose and the harmonic balancer off of the crank in order to get the old pump out and the new one in.

I also repplaced the thermostat and teh radiator before getting to the water pump because I could not believe that anyone would put a watrer pump on a car with a plastic impeller, and many houes and many $ later I know different. let me know if you have any other questions. The other thing you might want to consider is replacing he timing belt and accessory belt while doing this work if you see fit.