Thread: Cooling system problem diagnosis

Checked the fluids and no leaks, all hoses and clamps good

I sometimes wonder if posters actually read the original post when replying.
I know I am sometimes guilty .
BUT for goodness sake, the problem is straight overheatiing and the overwhelming odds are that the radiator is blocked and/or the viscous has failed. These two items would comprise 90% or more of incidents causing overheating.
Why post about the rad tank when the poster has said he is not losing water?
It just confuses the issue and IMHO lessens the resolve of the poster to take what is expensive but necessary action to fix the problem.
Regards Philip A

Last night I decided to test the waterpump (well I think I tested it). Let me know if my logic is flawed.
I assumed (that could be my main mistake) that water travels from the top hose thru the radiator and from bottom hose to the pump, pumped from there thru the block and via the thermastat back to top hose. I hope thats the way it works. Anyway took top hose off the radiator and proped it higher than radiator,took top up plug on top of radiator off and placed hose in to continuously keep water in radiator full (given it could escape through the top of radiator and wouldnt over fill anyway). Started car and no water out of top hose, waited for thermostat to open and then just a small dribble which soon stopped. My conclusion then was that the pump is stuffed.
Also was looking on a you tube clip on changing water pumps on a P38 and the guy doing the clip stated if the fan is wobbly on the shaft then the bearing in the pump is gone.
The second thing is how the hell is that viscous fan unit secured to the shaft. Mine is on the front of the fan and has some spring in the middle and no visible bolts other than the four connecting the fan to the plate on the rear of the viscous unit.
Seems I will need to be pulling the radiator out just to get the cowling cover off so I can see whats going on. Is there any advise other than to take it to a mechanic as I prefer to get dirty with the car and learn how it operates so if failure occurs in the bush I will be better clued up on a fix.

Not a good test. Just take the thermostat out, top hose off the radiator and fill the rad. Start the engine and see the flow out of the top hose. There's no point trying to warm it up to open the thermostat, you will get an air lock. Cold water from your hose will prevent the thermostat from opening too.

For removing the fan you will need a fan spanner (36mm?) on the hex boss near the pump, and a hammer. Apply spanner and hit to rotate in a clockwise direction to unscrew it from the water pump. It is on a left hand thread.

thanks bee utey, will try your way and believe I will get the same result.
Is it neccessary to take radiator out to get that cowling off or can you carefully bend it and slide it up the front between fan and radiator. can't see any other way than removing the radiator to give clearance.

Get a fan spanner first, when the fan is off the cowling should slide up. A fan spanner should be available from most parts places, as this fan type is commonly fitted, especially to Fords.

Thanks for the heads up bee utey.

Well did as advised and water is definetly coming out the top hose. So it looks as though the viscous is the culprit.......if it was so easy. After testing and reconnecting the top pipe I filled up the radiator and block and what do you know it all starts draining from the back of the engine somewhere. Hard to pinpoint where it was leaking from as the car was parked on a slant nose up and the water was coming fairly rapidly from the top of the bell housing. I 'll have to waiit till I have a check in daylight but suspect I have blown a heater hose at the back. The welsh plugs that I could see seemed ok so unless there is one at the back of the block somewhere although I suspect a hose from something located at the rear of the block and not visible because of the plenium chamber and various other bits and pieces.
I can see the heater hoses on the right hand side of the block entering the firewall and they seem dry so suspect a blown hose at the block hidden away somewhere or something else. Seems crazy that it had no leaks previously , I may have started the "classic" domino effect. any advise appreciated.

Remember water spilt on the inlet manifold gasket will run through the valley and down the back of the engine. So look at the thermostat gasket first. Sometimes the thermostat slips down during reassembly and causes a leak. A bit of super glue will hold it.