Temp sender unit

[Chug]

The temp gauge in my tipper hasn't worked since I got it last summer, I looked at the sender unit and its different to any other Transit DI I've had before, its like the old cortina/granada sender units with just one wire.

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I checked the wire and it has 12v feed and if the wire is earthed the guage goes all the way up to max so all seems ok there.

I went to a good local motorist shop and they couldn't find anything like it listed for Transit 2.5 DI (all multiplug wired)but they managed to find a similar one for me, with a different coloured band around the top.

I fitted it and it sort of worked but the gauge went just past halfway and just into the red at normal engine running temp (the engine wasn't hot) and when I looked again later it had stopped working and the gauge was right back at the bottom, I've still got 12v feed to the wire so I assume the sender unit was either, the wrong one, was a duffer, or it has just packed in.

Question: Has anyone seen a 2.5DI with this type of sender unit and does anyone know which sender unit I need (part number) and where to get one please?

[Chug]

I have goggled for this sender and had no luck, I can find lots of temp senders for petrol fords but nothing for a DI transit.
They have different colour tops, the one fitted to mine has a red top, I don't know if the fifferent coloured tops are for different temp ranges, Does anyone know?

This is the thermostat housing and the sender unit is underneath the top hose and to the rear of the housing.

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[cherniy_chack]

Chuggy,I recently changed the temperature sensor. I came to the seller of spare parts and said, on Transit I need a sensor. He sold me a sensor with a brown top. With one output.
I installed the sensor on the motor.
The temperature gauge shows correctly.

[Chug]

Upon cleaning up and close inspection my sender unit has a brown top, so I bought a new brown top sender unit today and fitted it and the gauge only gets to the start of the blue bit when warmed up, so this brown one is reading low, I have previously tried a white top one and that one read too high.

[cherniy_chack]

Chuggy,oh, those old cars!
If you know how to use a multimeter, you can choose a temperature sensor from the measured resistance value of the sensor.
The brown sensor gives low readings, white-high.
Hence the resistance of the white sensor is less than the resistance of the brown sensor.
You can be satisfied with a sensor that has a lower resistance at the same temperature than a brown one, but higher than a white one.
The semiconductor temperature sensors have a large spread of resistance, so your new brown sensor gives incorrect readings.
It happens.

[Chug]

I decided to check the thermostat today, typically both housing bolts snapped off, but I managed to remove the broken stubs with some heat and lockjaw grips.

I warmed up the thermostat in a pan of water with a temp gauge and it opens around 60C, so I dug out another thermostat which opens around 90C, now my gauge gets up to the N in the "Norm" section when at running temp and when going up a big hill it gets to the R in the "Norm" section so I'm happy with that, plus the heater is running hotter now too!

[cherniy_chack]

Chuggy ,there is such a Russian saying: "The casket just opened ..."
When you communicate on the Internet, you assume that the interlocutor did everything possible and faced an incomprehensible problem. But often it happens that the cause of the problem is different.
As in your case.
I'm pleased to learn that you have figured out the problem yourself and fixed the malfunction.

[Chug]

Thanks cherniy_chack it was you saying that you had a brown top that made me clean mine and look closely with my glasses on and find that it was a brown top and not red, otherwise I may have bought a red one and wasted my money.