Any Ford Focus experts here?

[Simon T]

OK, got a very strange problem with my Ford Focus's cooling system, not sure if there's a blockage somewhere and might be overheating.

First a quick summary of the events leading up to the apparent problem.

There was a leak coming from my cars thermostat housing the other week, so replaced the housing, the stat and the seals (all brand new from local Ford dealer).

Took it for a test spin after refilling, noticed both cooling fans were coming on, despite the fact the bottom radiator hose coming from the thermostat was still cold and the temp gauge was still "normal".

Assumed it was an airlock, so stopped, gently turned the filler cap on the expansion tank to release the pressure. There was a lot of bubbling, which I thought meant it was just air pockets escaping. After I restarted all seemed well.

However, I've noticed that the cooling fans keep coming on when I'm driving around, even though the temp gauge says the temperature is normal and the bottom radiator hose is cold. When I stop and release the pressure on the expansion tank, there's a lot of bubbling water coming from the hose that feeds back into the tank from the top of the engine block and the fans stop for a while.

Tried flushing the radiator through to see if there was a problem there, flushed through fine.

So, if it is overheating, then why isn't it showing up on the gauge? If it isn't overheating, then why are the cooling fans coming on when there's no flow of water through the radiator?

If I didn't know better I'd say it was a combination of faulty thermostat and temperature gauge not giving the correct reading. However as the stat is brand new I'd like to assume it isn't that.

Any other suggestions what the problem might be before having to take the thermostat back out for testing? Don't really want to do that if I don't have to as its an absolute swine to get to, being sandwiched between the alternator and air-con cooling pump, meaning a major strip down. Wouldn't have thought it would have been the thermostat with it being brand new, but don;t know what else it could be? Engine is supposed to run at 82 degrees and bought the correct stat.

The car is a V reg Ford focus, 1.6 petrol, with a Zetec engine. UK model.

Any suggestions gratefully appreciated.

[Allan Mac]

Angel)

HI

if it was the stat I would have thought there would either be a serious boil up, or it would never warm up properly. If you squeeze the bottom hose can you actually feel coolant in there, and does the heater work normally ? Sorry no real help ! Allan.

[Simon T]

When I squeeze the bottom hose it does feel like there's coolant there, Not sure about the internal heaters as the ventilation fan is knackered, waiting for some replacement brushes off ebay so I can get it going again (not paying £200 for a new bloody fan).

Does seem strange that both the radiator fans are coming on after a relatively short distance (couple of miles down the road), despite the fact the radiator is cold?

[Dave Plowman (News)]

Does it have different sensors for the fan and temperature gauge? If so, there could be air trapped which is making one read wrong.

I assume there are no bleed valves on the cooling system?

If not, can you park up on a slope so the filler is as high as possible?

Fill to the top when cold or cool, then start the engine with the cap still off. Leave idling until the stat opens - you should see some air being expelled while waiting. When the stat opens (the top hose starting to get warm) top up and fit the cap. It will likely force out some coolant down to its required level as it heats up to maximum.

[Dave Baker]

Post it on Pistonheads in the engine tech section. Someone will help.

[polygonum]

Water pump?

[SteveW]

Is the air-con switched on - ISTR that on at least some cars, it uses the radiator cooling fan(s).

SteveW

[Simon T]

Think that might have done the trick.

I had to take the car for a spin around the block to get it up to temperature, as it was taking ages sat idling, then slowly released the cap.

There was a lot of glugging about from the pipe at the top again, then after a minute or two it seemed to stop. Felt the bottom pipe and it appeared to be getting warm. Think your suggestion MAY have done the trick, as I went for another spin around the block and the radiator appeared to be warm and the fans weren't coming on, so I'll go for a longer drive out later and see what happens.

I'll post here again if its still playing up (failing that I'll try Pistonheads, as someone else suggested).

[The Natural Philosopher]

water pump gone?

And their sensors are in the block, not the rad?

[alan]

Fan or thermal fuse?

[alan]

On my 2001 Focus the AC comes on (without showing the AC light) if the controls are set to blow air at the windscreen. The AC removes moisture from the air before being heated to demist the windscreen. I believe the AC can use both radiator fans.

[harry]

Run the (cold) engine at fast idle with the radiator cap off and look down the hole to see what happens. If you get bubbles, combustion gases are getting into the cooling jacket. Usually cylinder head gasket blown. Verify with compression test

Also check oil filler cap for white scum, Coolant leaking into engine oil.

[Simon T]

It was the brushes on the fan, they'd worn down to practically nothing. Managed to get some replacement brushes off ebay (which were delivered mid-morning) that were about the right size, and with a little bit of filing and some jiggery pokery with a soldering iron, got the ventilation fan going again this afternoon.

[Simon T]

Nope, still playing up. Reckon the bottom hose was only getting warm because the hot water from the top hose was feeding backwards through the rad once I took the cap off the expansion tank.

Right now my money is on dicky thermostat because the pipe going from the stat to the bottom of the rad is cold.

Still doesn't explain why the temp gauge on the dash still reads "normal"?

*sigh"

[Simon T]

Doesn't appear to be any of those, as I posted elsewhere, at this moment my money is on Ford selling me a dodgy t/stat.

[Reentrant]

As it's a Ford - Anglia grinder

[alan]

The Haynes manual for a 2001 focus suggests that there is a air bleed valve on the thermostat (replacement part) itself and that the part has to be installed correctly.

The manuals advice about refilling and airlocks. Fill SLOWLY through the expansion vessel filler cap. Squeeze hoses Temperature cycle See 2nd image on the above link

[Dave Liquorice]

I'd still go for an airlock. With the cap off have you: run the engine with the heater/air con set to full hot (fan working or not). massaged all the hoses? Are any of those hoses high relative to the top of the rad or where the expansion tank connects to the system?

A google on "focus airlock" produces lots of hits... you can probably narrow those down to you engine and maybe even get the refilling procedure or at least hints as to how to get the air out.

[F Murtz]

Stick the thermostat in a pot of water on the stove,when the water gets hot you can see it open if it is working. This will eliminate one possible problem.

[Simon T]

I'm sure I put that at the top, also I've fixed the ventilation fan and the hot air gets warm very quickly, which would appear to indicate there's no air lock there.

I'm going to test the water pump next.

Failing that, I'll be stripping the engine down again Monday to test the stat!