13 replies to this topic

[new_horizon]

Hi All,

I've recently purchased a 2007 Fiesta TDCi with 35k on the clock and think I may have got more than I bargained for.

A bit of background on the car - it is one lady owner from new, has only covered 37k and has full service history (not Ford). In general, the car is in excellent condition and appears to have been well maintained.

When I purchased the car, the lady told me that the car overheated intermittently at around 70 mph. I took it on a test drive and was unable to replicate the problem despite several attempts. She said that the garage had told her that the thermostat was the likely culprit.

Anyway, as I was driving it home on the M25, the temperature gauge shot up so I quickly pulled over. The car cooled down almost immediately and the needle plumetted back to half way. I drove it again and kept it at 50 mph with no issue. I was able to drive at 70 mph with the heaters on full and the windows dropped for the hour long drive home.

I had the thermostat changed and the problem persisted...this to me suggests that I may have bought a bigger problem. So my questions are...

1) Has anyone experienced anything similar on the TDCi engine?
2) Can anyone offer any advise on the likely culprit? I'm arranging for a pressure test to be carried out on the engine next week as I've been told by a mechanic friend that the engines are the same as the Peugeot and may have a head gasket issue.

I'm expecting head gasket or waterpump to be honest, but would rather save time and money by getting some advice from the forum.

Any help is much appreciated,

Best wishes,

Mark

[DieselPig]

You say it cooled down almost immediately! Sounds more like a bad connection to the engine temperature sensor or a dicky sensor.

If the head gasket is blown it would be using water and blowing it out of the expansion tank. Check the colour of the water in the expansion tank, should be clean and oil free.

[new_horizon]

Thanks for your reply. How can I check a faulty sensor? I replaced the thermostat and thermostat housing, which I thought would have fixed this issue...

Yeah pretty immediately-I'd say it takes 20 seconds to completely return to normal temperature...

I haven't noticed any water loss and the water is clean. Compression test happening on Monday. I just can't believe a head gasket on a car with so few miles

[DieselPig]

Sensor itself is cheap, check the connection first may just be loose or corroded. Get the garage to test it.

[new_horizon]

Hmm noticed today that the top radiator hose is hot but the bottom one is stone cold under normal operating temperature. Suggests a circulation issue-blocked radiator or perhaps inefficient water pump?

[b1g_dav3]

Not sure on the Mk6's, but the pump's on the Mk7's are junk.

Have a look on it for signs of corrosion, as there's no way under the use it's had it should have wear and tear on your parts really. Only thing I can think of is corrosion on the thermostat (which has been swapped out) or water pump. Is the fan kicking in when the heat's going up?

[DieselPig]

Bit young for water pump failure! Could be the old problem of the impeller parting company with the shaft and therefore no circulation.

[b1g_dav3]

You say that, yet I had my water pump changed at 14k although I heard the problem of it at about 1500 miles but the useless dealer said oh no nothing's wrong...

[DieselPig]

Luck of the draw really, in 35+ years of motoring I've only replaced one water pump at 128K miles on a Fiesta.

[new_horizon]

I'll check the waterpump for corrosion when I get a second-I wouldn't have thought that at 36k much should be failing at all but I suppose you never know!

The fan is cutting in and out as it should be so we can rule that and the thermostat out...

Ideas are welcome as always as I think I'm going to have to change the waterpump-which is going to be quite costly I'd imagine on labour

[new_horizon]

Can I ask what might be a slightly naive question? If the waterpump was indeed at fault-would the car not overheat at other speeds? Just throwing it out there as it's only 50 mph +

[DieselPig]

Assume the pump has failed there may be some impeller movement so a bit of water is moving plus there is the thermo syphon principle involved. Many moons ago cars did not have water pumps but relied on this principle, bit different now with a small car producing 100 HP and lots of heat!

A mate had a Mondeo V6 with the same symptoms and the plastic impeller had split, it was still on the shaft but at high speed it was not rotating quick enough to move the water through the radiator and hence it would overheat, new pump problem fixed.

[stef123]

these engines will have an oil cooler? is it possible its lacking oil flow or the thermostat for it is stuck? when the engine is working hard to keep the car going at speed the oil must be getting pretty hot..

just an idea if its not water pump or radiator thermostat related.

[new_horizon]

Thanks Stef and Diesel. I think it's going to have to be a new waterpump-do you have any idea if this requires the cambelt having to come off?

Your advice has been really appreciated