Temperature Sensor

H

hillbill

A2OC Donor
I've been having issues with my temprature gague and have already replaced the Thermostat, so after a quick search on here, i have diagnosed it to be the Temperature Sensor. I have read up on here that some early A2's had a 2 pin Sensor and later have a 4 pin, so as mine is an early A2, I thought it would be best to check first before ordering a new one. I couldn't remove the connector, as it was in an awkward position and was getting dark but i did notice it had 4 wires going into the rear of the connector, so my question is " will my temprature sensor be a 4 pin, as i have 4 wires going into the rear of it"?

Thanks Darren
 
hillbill said:
I've been having issues with my temprature gague and have already replaced the Thermostat, so after a quick search on here, i have diagnosed it to be the Temperature Sensor. I have read up on here that some early A2's had a 2 pin Sensor and later have a 4 pin, so as mine is an early A2, I thought it would be best to check first before ordering a new one. I couldn't remove the connector, as it was in an awkward position and was getting dark but i did notice it had 4 wires going into the rear of the connector, so my question is " will my temprature sensor be a 4 pin, as i have 4 wires going into the rear of it"?

Thanks Darren
Click to expand...

HI Darren,

I think that you will find that the confusion is caused by there being two temperature senders, one controls the fan, the other has a dual purpose (hence the 4 pins, two for each) I am not aware of this being a "date" thing, I believe that all A2s have the dual (four pin) sensor that affects the gauge and ECU.

Yours will therefore be a 4 pin for sure.

Steve B
 
Hi Darren,

Just a few words of advice.

Buy genuine for all sensors if possible.

Non-genuine sensors can be unreliable, and if you have an unreliable temp sensor (or its O-ring) for example, then you'll also waste coolant when you need to replace a faulty item, so even though you may get your money back for the item, you'd be out of pocket.
When changing the dual temp sensor, make sure you get a new O-ring, and it's worth spending 50p on buying a new plastic clip that holds it in place, because if you drop the old one you'll swear.

Cheers
Jeff
 
Doesnt the genuine part give an o ring and clip?
I got about cheapy on ebay recommended by another forum.
Works as it should.
 
chubbybrown said:
Doesnt the genuine part give an o ring and clip?
I got about cheapy on ebay recommended by another forum.
Works as it should.
Click to expand...
Not as standard. If the parts guy is on the ball he will include all three and give you a price. But since you can buy each part individually you might have to ask for them explicitly.
Steve B
 
@chubbybrown,

I'd suggest you got a little lucky, if indeed it is working correctly.
I've seen many a cheap ebay sensor fail for one reason or another.

As they are dual sensors, it's not only the temperature gauge that should read correct, but also the ECU.
One half of the sensor send a signal to the gauge and the other half sends a signal to the ECU for fuel/air mixture.
If the gauge works as it should but the ECU is receiving an incorrect signal you'll not necessarily know about it until you investigate why your fuel costs have risen.

Both sides of the sensor work (or fail) independantely of each other.

Just to add fairness, I've also seen many non OE sensors without problems.

Unfortunately the genuine parts are all seperate items - see below for part No's and approximate cost:

Dual Temp sensor
059 919 501 A
Approx. price inc VAT - £40

O-Ring
N 903 168 01
Approx. price inc VAT - £1.70

Retaining clip
032 121 142
Approx. price inc VAT - £0.75

Coolant - G13 - 2lts
Approx £20

Cheers
Jeff
 
Thanks Jeff.
Mine came supplied with new o ring and clip.
I still have the original as in the end it was a dodgy thermostat.
I suppose 11969 feed back and 2 year warranty swung it for me for £6.00
Purvue is the ebay seller
 
Just done this job. The key is to give yourself a bit of room. Remove engine cover, charge air pipe and wiring holding bracket that is adjacent. Removed the clip and before removing the sensor had about 10 practice goes at fitting the clip. It has to be fitted vertically.

Withdrew old and popped in new, lost about an egg cup full of coolant. Grand, or so I thought, the clip would not fit, no way no how.

Checked old sensor, photo'd to compare with new and realised old 'O' ring had stayed in housing so had been trying to fit with 2 'O' rings.

Lost about 2pints of coolant trying to get old 'O' ring out.

Temperature guage now works well again.

Location with wiring bracket fitted

https://www.dropbox.com/s/21ibacp9wyyu4qe/DSC_0247.JPG?dl=0


Shows clip partially removed

https://www.dropbox.com/s/y68n5zp8bj8qcmn/DSC_0250.JPG?dl=0

 
Last edited:
oneflewover said:
Just done this job. The key is to give yourself a bit of room. Remove engine cover, charge air pipe and wiring holding bracket that is adjacent. Removed the clip and before removing the sensor had about 10 practice goes at fitting the clip. It has to be fitted vertically.

Withdrew old and popped in new, lost about an egg cup full of coolant. Grand, or so I thought, the clip would not fit, no way no how.

Checked old sensor, photo'd to compare with new and realised old 'O' ring had stayed in housing so had been trying to fit with 2 'O' rings.

Lost about 2pints of coolant trying to get old 'O' ring out.

Temperature guage now works well again.

Location with wiring bracket fitted

https://www.dropbox.com/s/hqdm8sfuazbdunh/DSC_0197.JPG?dl=0


Shows clip partially removed

https://www.dropbox.com/s/y68n5zp8bj8qcmn/DSC_0250.JPG?dl=0
Click to expand...

Yes - most of the time the O ring gets left behind when removing the old sensor, and therefore you will need replacement coolant once you've finished fishing for the old one.

Just for info too, but the first image is not relevant to this post.......it shows the wiper arm.

Cheers
Jeff
 
I eventually got around to fitting the new sensor and it wasn't too hard of a job, taking about 30 minutes.

The only issue I found when doing the job, was the wire connection was a little awkward to remove, due to the location of the sensor, which meant you could only really use one hand, and the hand you were using was forced at a weird angle, meaning you struggle to get enough grip/strength to release the connector. Eventually I realised that you could turn the sensor in it's housing 180 degrees, which enabled me to get the pressure on the release part of the connecter, making it a lot easier to remove.

I used a pair of pliers to put the clip back in, as I found I had more control inserting it into the location.

The temperature gauge functions perfectly now, so it's well worth the small amount of time and money to do this job yourself.


Thanks for all the help...
 
Many thanks to all contributors, I just did the job on my TDI 90.

I couldn't release the connector like hillbill so I pulled the clip out and then the sensor with the wiring still attached, then it was easy to release the connector.
In the second photo from oneflewover, you can see that the middle hose clip is in the way of the sensor clip, and I found the job was eased a good deal by turning the clip around the hose clockwise to give a bit more room. You need to nudge the spring clip from both ends with something to "break it away" otherwise it remains stuck to the hose and won't turn.

I agree tying some button thread around the clip and then tying the other end to a fixed bit of the engine is a good way to recover the clip if you drop it.

The sensor was from Murray MacDonald in Hatfield and is a Beru brand, I think it's effectively an OE part rather than pattern.

All the best,

Matt
 
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