Strange Mondeo Cooling/Aircon problem

-westy-

-westy-

-westy-

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7 Nov 2002
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Snorbans, UK
Hi,

The car in question is a Ford Mondeo 2.0 Petrol Zetec, on a 51 plate.

The car itself is sound apart from one fault, which I've noticed this evening.

Driving towards town (about 15 miles away), I noticed that the temperature gauge hadn't moved, it was sitting on the bottom. I had the aircon on, albeit at an average temperature (somewhere in the middle of the gauge). As soon as I turned the aircon off and kept the temperature the same, the temperature gauge came back up to the middle (as it should). I stopped the car and turned the engine off. When I restarted, the idle was around 1200rpm, as if the car was cold (it had already been driven 11 miles).

Playing with it a bit more, I noticed a correlation between the aircon being on, and the position of the temperature gauge.

Would I be right in thinking this is an electrical issue, rather than mechanical? When the temperature need dropped, it did so very quickly - its not possible for coolant temperature to fall that fast!

Hence my thought being the coolant temperature sensor at fault.

Any ideas?

Cheers :)
 
My old Mondeo TD did this, A/C on, temp guage read cold, off it read normal. I assume its a fault & never bothered to get it sorted, removing the expansion cap proved the coolant was anything but cool!!!

O/T Taunton? My Gran lives in Priorswood! - lovely part of the world imo. :)
 
Yes, its very weird. Arriving at work this morning and the temp gauge hadn't moved, and the heaters weren't that warm, either. I'm suspecting either the CTS or thermostat?
 
Thermostat on my mk3 fixed this, went from barely warm in 30 miles to warm air by the end of my street!
 
Yes, that sounds like a dodgy stat, strange thing with my old Mondeo was the heater was fine, if anything too damn hot!
 
Does having the aircon on also result in the cooling fans constantly running as it doesn on many cars? This combined with a thermostat which is stuck open would explain what you are seeing.
 
It can be a bit more effort to start, and the idle is high - I've ordered a new CTS, as I don't think that the coolant temperature could fall that fast! (30 seconds or so..).
 
There's a guide somewhere on fordwiki for displaying the actual cht in the instrument cluster, should help make sure of the problem!
 
Dad had a 1.8 or 2.0 (tbh I have completely forgotten!) 02 reg mondeo from 2002 to 2005/6

From 80 miles to 80,000 miles all it really had in non-consumables was a thermostat and I remember there being an issue with the temperature gauge.

I have no idea if this is of any help to you but hope it is! It was a petrol btw.
 
I can't get my instrument cluster to go into Self-Diagnostic mode :/ following the instructions on FordWiki...any ideas?
 
Don't know what to suggest there really, just make sure you push the trip reset firmly and turn the ignition so the dash lights come on and it should do the dial sweep after a second or so, unfortunately I no longer have a Mondeo to test!
 
-westy- said:
I can't get my instrument cluster to go into Self-Diagnostic mode :/ following the instructions on FordWiki...any ideas?
Click to expand...

Hold down the trip reset (the one on the right) and turn the ignition fully on, then wait until it says test on the display. Then let go.
 
Finally got it working - and from sitting there for about 10 minutes, the Cylinder Head Temperature drops whenever I use the aircon, whether its on a hot or cold setting.

As far as I'm aware, the Aircon and cooling system were seperate, so what could be causing this? Am I still looking at the thermostat?
 
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