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Matt, Mechanical Engineer
Category: Ford
Satisfied Customers: 22907
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a mondeo st220 2002.for some reason it's overhearing

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Hi. I have a mondeo st220 2002.for some reason it's overhearing and I have steam coming out the pressure cap, the display temp is reading half way/normal. I took the two top pipes of the coolant reservoir and when running, no water was coming out. Would it be water pump issue?
Customer: replied 1 year ago.
Can someone answer me please?
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.


sorry about the delay in replying

the 2 pipes that run back to the header tank should be flowing water in a steady stream

so either there's a large air lock or the water pump is faulty

The other thing to try is a head gasket / block test kit as these take a coolant sample and analyse it for any signs of combustion gas - if present this would indicate the head gasket is on its way out

If this is OK then I'd consider to replace the thermostat in the engine.

Whilst the thermostat is being replaced you might as well also reverse flush the cooling circuit (remove top hose to rad and use a hosepipe to push water into the engine until you get clear water out of the radiator hose) and top up with 30-50% fresh antifreeze. Also check that the small diameter bleed hoses that run from the top of the radiator and the top of the engine aren't blocked as this allow the air to vent back to the header tank automatically.

If you still have a problem then check that the water pump impeller / turbine isn't spinning on its shaft. You should be able to achieve this by removing the bottom hose from the engine and use a screwdriver or similar to feel for the water pump impeller blades, whilst your assistant turns the engine over by hand.

If you can stop the impeller with slight pressure from the screwdriver the pump needs replacing.

Also its possible the belt is slipping so its worth replacing its especially if the rubber ribs are cracked or it looks shiny on flat side of the belt - while its off check that the tensioner and other pulleys all spin freely the exception to this is the AC pump ( if fitted)

I'd also suggest ensuring that you've got all the air out of the system as this sort of episode can leave pockets of air trapped and prevent the coolant from circulating properly.

So check that the small hoses that run from the top of the engine and radiator that run back to the header / expansion tank are free flowing and not blocked

If these are OK then remove the tank pressure cap and run the engine from cold with the heater set to full hot

As the engine starts to warm, squeeze the large hoses running to the radiator to help displace any air - all the time keeping an eye on the level in the header tank, making sure it doesn't drop below the minimum and open any bleed screws built into the top cooling hoses - closing them off as soon as they start to gush water

Once the engine is up to temperature the tank should be quite full. Switch the engine off and leave it to cool

Then top up to the mark once its all cold and replace the cap

Customer: replied 1 year ago.
Ok thanks, ***** ***** the thermostat is OK as all the hoses seem to be hot and so does the radiator.


in that case I'd push on with the chemical test as I'm sorry to say its quite likely to be a failed head gasket


do you still need help?

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Customer: replied 1 year ago.
I have bought a new expansion tank cap and replaced the thermostat myself but can't test it yet as I have broken a pipe on the water pump housing. Was replacing the water pump but it seems ok and the impellers are ok.


best to do the chemical test once its all back together then

Customer: replied 1 year ago.
That's when you test the vapour in the coolant reservoir tank, once its been running.?

thats correct, you take a sample of coolant once its run a while and then put it into the kit

Customer: replied 1 year ago.
Ok I thought the one I was looking at just tested the vapour, not the coolant. Will check. Would the faulty pressure cap have caused over heating? And an air lock?. What other symptoms would tell you its a head gasket.? I have no oil in the water, no mayo on the oil filler cap and she runs fine apart from the over heating issue.


you could do a compression test across all cylinders

as they should all be within 10-15 psi of each other as this can also show gasket issues

and yes a faulty pressure cap can also cause overheating

Customer: replied 1 year ago.
Once I get it up and running I will get a compression test done. That will tell me which head has failed, fingers crossed they have nt. In your opinion do any of These solutions that repair head gaskets actually work?


actually I have used this stuff in the past with good results , in 1 case 20K miles plus

Customer: replied 1 year ago.
Can I ask what make?, steel seal or. K seal ? Thanks


actually just the K.Seal

but they do make something superior now so I'd give that a go

Customer: replied 1 year ago.
I was reading up on steel seal and as its a v6 I would need to bottles. I guess you just Pour it in with your coolant. If you did a compression test after that and it worked would it be back normal then?


yes it works pretty quickly

basically goes in a cold engine and once you've run it up to temperature and let it idle for about 10 minutes its usually sealed

Customer: replied 1 year ago.
Well if I need to use it I will. One last question then I will go Matt. Being mine is an early one my water pump housing g has a pulley. The later ones don't. Will my belt fit on there's as I believe the housing I have ordered is off a later mk 3?


I think that there's very little difference between the 2 belts and in any case the tensioner will accommodate small changes

Customer: replied 1 year ago.
I believe the later one does nt have a tensioner though. I don't know if my tensioner pulley would fit on that one or not.


any flat belt will need a tensioner unless its one of the very latest type which shorten themselves and self tension in use ( and have to be cut off)

to my knowledge its the same belt for this engine up until 2007

Matt and other Ford Specialists are ready to help you
Customer: replied 1 year ago.
I think it's off a 2007 car so will have to see if mine will fit. Thanks Matt.