Mondeo temp gauge

Need a little help figuring out a problem that has me, a mondeo specialist and Ford main dealer stumped !

2004 Mondeo TDCi. Temp gauge not reaching proper position, hardly moves past cold.

Mondeo specialist has changed coolant thermostat - no difference. All pipes and expansion tank getting warm, heat coming from vents. Temperature sensor not changed but specialist says these 'never go wrong, if they do engine won't start'. Using the odometer diagnostics the temperature never goes above 53c, starts at 40c when cold and after 2 miles driving steadily rises to about 45c, takes another 6 or so miles to get to 50c'ish but no higher. If I drive the car hard I can get it up to 60c but it drops back down quickly if I back off. When the mechanic thrashed it inside the garage for a few minutes the gauge went to the 12 o'clock position but as soon as he went onto the road it immediately fell to cold again. My mechanic has contacted Ford who can't offer a solution other than to bring it down and stick it on the diagnostics, they've never heard of such a problem before. Mechanic can find no fault, engine getting warm, cooling fan cuts in when it should, no blockages in pipes, thermostat changed, heat coming from vents.

I've done a bit of googling and it seems a lot of people have had this problem starting in the last year or so on 04 models. It also seems there may be an oil cooler stat, which a lot of Ford dealers deny any knowledge of and may be part of the problem. But even those who have changed oil and coolant stats as well as the sensor still seem to have the problem.

What could be the problem, I suspect maybe the sensor but the 'experts' say different. Speaking of which can anyone give me an idiots guide as to exactly where it's on the block as I've heard a faulty connection can give the wrong resistance and cleaning the terminals might fix it. Thanks.

Reply to
jj
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What is the heater like? Does it's performance mimic the gauge?

I would put money on a 2nd duff thermostat, or other installation issue with it.

Tim..

Reply to
Tim..

jj was thinking very hard :

The gauge reflects the OBD's temperature, so they must be OK. From cold, run the engine and feel the top hose - if that suddenly turns from cold to hot, that would seem to confirm the stat is OK. Which then only really leaves the temperature sensor being faulty, despite opinions to the contrary.

Unplugging the sensor normally causes the gauge reading to show cold, shorting the tip of the plug end to ground, normally causes the gauge to show maximum hot.

Reply to
Harry Bloomfield

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