Puma Over Heating

Hi,

My son has a 2000, 1.7 Puma which developed a water leak last week.

He used Radweld as a temporary fix and I got the job to fix it properly.

I found that the plastic thermostat cover had cracked - a common fault I'm told.

I replaced top and bottom radiator hoses, the heater hoses, thermostat and cover and flushed out the block, radiator and heater and also replaced the radiator cap.

I rebuilt the car, filled the cooling system with antifreeze and the system is no longer leaking and is pressuring as you would expect.

The only trouble is that it is now overheating. I changed the temperature sensor and this made no difference.

I am sure there is no head gasket leak and I have checked that water is reaching the temperature sensor and that the temperature gauge is OK.

My son says that on long journeys he has noticed for some time that the radiator fan will operate continually but the gauge temperature has not been above the normal position which suggests that slight overheating may have been present for some time.

I can only think that either the new thermostat is faulty, the impeller is loose on the water pump, or there is a blockage in the head. I have never heard of an impeller coming loose or a blocked head.

Any ideas?

Ok - So I've removed the thermostat and tested it and it starts to open at above 80 degrees centigrade and it well open before boiling point.

The water pump is next to the thermostat housing and it is possible to check that the impeller is not loose by feel and this is OK with no blocked vanes.

So I am left with a blocked water way. Looking at the old thermostat cover it looks like a piece 10mm x 19mm x 1mm has flaked of the inside.

Is it possible this has been picked up by the water pump and pushed into the water jacket?

I guess I need to get the water pump off to check.

Is it possible to remove the water pump with the engine in the car.

Is it possible to remove the water pump without disturbing the timing belt/chest?

Does any body out there know?

In the mean time I have back flushed the block and I am sure this has moved the blockage but I still need to remove the water pump. I guess I have to start by removing the pulley but how many bolts retain the water pump? It is rather difficult to tell.

So, I've managed to remove the water pump. You first have to remove the pulley which is fairly straight forward and then the timing belt cover which is more difficult as the only way of locating the fixing screws is by feel as vision is very limited. Now you can access the six water pump fixing bolts, three of which you again have to find solely by feel. couple to this it is very difficult to get even a small socket racket in the available space. Once this is done the water pump comes away easily.

The trouble is there is no debris behind the pump which I was hoping to find.

I am fairly sure the blockage has moved but where to? The last thing I want is to re-assembly everything only to find the blockage re-occurs. I have tried further back flushing but no debris appears. What I find amazing is how slim the water jacket is - a wonderful bit of casting.

I think I will try flushing in the normal direction of water flow and see if this again causes the blockage to occur - unless anyone has any other suggestion. I only want to remove the cylinder head as a last resort.