Golf mkiv temperature guage sender

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Fri 6 Apr 2007 11:57
Golf mkiv temperature guage sender - Ian J
Hello all
I am looking for some help to explain what is happening and how to solve a problem with the temperature sender on a 1.4 petrol mkiv golf. Basically the temperature needle in the dash stays at o ie it dosent rise until you wiggle the temperature sender ( THE BODY OF THE SENDER NOT THE ELECTRICAL CONNECTION ) which is located in the coolant hose. After that is done the temperature guage rises to normal and continues to work normally. I dont think the problem is electrical since I am not moving the electrical plug, and after this is done the temperature sender is working normally. It appears as if there is an air lock or something blocking the hot water reaching the temperature sender.
Can anyone explain what is happening- I am not convinced that changing the temperature sensor will solve the problem since the existing one works normally after it is moved around or wiggled.
Kind Regards
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Fri 6 Apr 2007 12:01
Golf mkiv temperature guage sender - jc2
Take the sender out-clean the threads on the sender and in it's hole and refit-sounds like a bad earth.
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Fri 6 Apr 2007 12:41
Golf mkiv temperature guage sender - Screwloose
Ian

These senders don't earth; they do fail on a regular basis though.

There shouldn't be any looseness in the body of the sender; note any coloured band on it and get a new one from the dealer.

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Fri 6 Apr 2007 15:12
Golf mkiv temperature guage sender - jc2
A two-wire sender -are they?
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Fri 6 Apr 2007 15:22
Golf mkiv temperature guage sender - Screwloose
jc2

Virtually all EFi VW's are 4-wire since about 1992.
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Fri 6 Apr 2007 15:38
Golf mkiv temperature guage sender - Ian J
Thanks for all the responses.

There is no looseness in the body of the sender - the movement is due to the fact that the sender is a press fit into the the rubber coolant hose it is not due to any movement in the sensor itself.

You are correct all the wiring is through the electrical plug in the end of the sensor and in my case of course they fitted the electrical plug upside down which makes accessing the push lug to undo the electrical plug connection very difficult to access.

Re fitting a replacement do you know how much coolant loss will occur.

Thanks again for the help

Ian
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Fri 6 Apr 2007 16:18
Golf mkiv temperature guage sender - Screwloose
Ian

Inside that sensor are two thermistors; one for the gauge, one for the injection. They routinely crack their wires or soldered connexions inside the sensor. If stressing the sensor body temporarily fixes it; this sounds very like a typical failure. These ECT sensor's lifespan averages around 5 years.

Loosen the filler cap to depressurize the coolant and retighten the cap. If you're fairly quick swapping them, you'll then lose less than a cupful; if you can catch it in a clean container, you can tip it back in.

Buy a new seal and clip with the genuine sensor - from a dealer - not some cheap and nasty copy. They can mess up your injection settings.
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