Temperature sensor

brigbeale said:

After disconnecting the Air Flow Meter to test it to see if black exhaust smoke decreases (which it did), I noticed that the temperature guage seems to take longer to register any temperature at all (it just sits at 60 degrees and eventually creeps up after about 10-20 minutes driving). I have already replaced the thermostat, so in theory, that should be OK (temp stays the same if stationary or moving).
Yesterday, on a 40 mile each way trip to Fareham on the motorway it just sat at 60. Only twice did it nudge past 60 for a minute or two and then return again.

I intend to replace the temperature sensor. It currently has the black one with 4 wires going in to it.
Do I need the green one or another black one?
I have read that one of them is considered pretty much useless from day one, but I cannot find the right thread on it. I vaguely remember that the 4 wire one is an upgraded part but can't remember which colour is the replacement.

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The standard temperature sender is the green one (4 contacts) get it form Audi, I bought one from eBay and it was faulty.

As for the temperature gauge taking a time before it moves, in my experience they are all like that, they seem to stay unmoved for a while and then then move reasonably quickly to 90.

But when up to temperature it should be reading 90, any less and you either have a thermostat problem (unlikely in your case) or a dodgy sender (most likely).

Steve B

£40.26 from Poole Audi.
Hope it's gold plated..........

brigbeale said:

£40.26 from Poole Audi.
Hope it's gold plated..........

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It is better value than a £9 unit that doesn't work, but you could always take a chance on an eBay one.
Remember that there are TWO sensors in this and not one, so even if the gauge reads correctly after you have fitted it, the other (more important) sensor may be bust and that controls the engine and mixture.

But I suppose that if you bought two from eBay and both were bust the third one might still mean that you have spent less than at Audi.

So it is up to you I guess.

Steve B

I decided on the genuine Audi route.

Drove into their car park and parked it in the only space available - end of the line where they have the sales cars displayed (next to an A1).

Went in to the building, couldn't see the parts desk anywhere. Went to ask a sales rep who completely blanked me (which I have had before at Mercedes Poole).

Eventually the main receptionist returned to her desk and called the parts dept to tell them I was there.

Parts rep came down from upstairs with a clear poly bag. I would have expected a box but hey ho!!. Paid my £40.21 and got my nice big invoice with the Audi logo in the middle of it.

Went outside and somebody was looking at my A2 and a rep was telling them it was not one of their sales cars.
I unlocked it and the daughter?? of the couple said she wanted one.
I think the wife would have killed me if I sold it!!

Got home and gave it 10 mins and then fitted the new one.
Found it easier to remove the bracket above it.
The clip slid out easily - surprised it is plastic - kept thinking to myself 'DON'T DROP IT!!'
Pulled out the old sender unit - turned out to be the green one - I was looking at the black plug initially - DOH!!
Water was still hot - ouch!!
Pulled the o-ring out - more hot water - ouch again!!
Put the new o-ring in and tried to put the new sender in after disconnecting the old one and plugging in the new one. It wouldn't go in so removed the o-ring and fitted it to the new sender and then pushed it in - success.
Slid clip in again still thinking 'DON'T DROP IT'

Checked it to make sure it was secure - could wobble it a bit and wondered if it was seated properly.
Filled it up with fresh coolant and kept an eye on the sensor. No leaks!!!

Ran the engine - temp guage started to rise. Got to 80 degrees and then phone went so had to switch off.
Returned to car after 5 mins on phone - no leaks still.
Replaced bonnet and had a celebratory cup of tea

Hi,

Yes, the coolant sensor swap is a bit novel, but reasonably easy. They normally sell you a new "C" Clip because they are so fragile.

The A2 would sell very well if they were to produce a very faithful updated version of it.

The problem is, the gap between the A1 ad the A3 is an odd one. The A1 always felt more claustrophobic than the A2 and it certainly felt smaller than the A2. The A3 has a bit more room (not a huge amount).

I am not sure that there really is a gap for the A2. But it looks like they are planning on a new A2, but I am not holding my breath and I expect the end result will not be an A2 as we know (and love) them.

Steve B

Birchall said:

Hi,

Yes, the coolant sensor swap is a bit novel, but reasonably easy. They normally sell you a new "C" Clip because they are so fragile.


I am not sure that there really is a gap for the A2. But it looks like they are planning on a new A2, but I am not holding my breath and I expect the end result will not be an A2 as we know (and love) them.

Steve B

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I agree.
I know the A2 as in my piccie was going to be electric but got dropped due to poor predicted sales as other manufactures did. Shame really.

No doubt a new A2 will probably be more like a standard car - like Mercedes and their A-Class. Missus loved the A-Class as a MPV but doesn't like the current version.

Did your Temp Gauge eventually sit bang on 90 degrees? if not, and even after fitting the sensor like me, you may need to change the Thermostat too. Again do not buy aftermarket...... instead buy a genuine VW/ Audi Thermostat.

meriafel said:

Did your Temp Gauge eventually sit bang on 90 degrees? if not, and even after fitting the sensor like me, you may need to change the Thermostat too. Again do not buy aftermarket...... instead buy a genuine VW/ Audi Thermostat.

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Dunno yet..... I haven't been able to take it on a long enough run. Have got up to just over 80 so far (temp not mph).

I can can share my experience. I bought a temp sensor from another brand real cheap because I didnt know it was so sensitive & would make a difference. My temp never did work well after that, took sometimes 40km to reach 90degrees plus it could drop down to 60 when ever it felt like it. So last week I went to Audi n bought a genuine one and since than it has worked well. Never dropped in the middle of a drive plusnit only takes 7-10km to reach 90 degrees now during the summer.

Maso said:

I can can share my experience. I bought a temp sensor from another brand real cheap because I didnt know it was so sensitive & would make a difference. My temp never did work well after that, took sometimes 40km to reach 90degrees plus it could drop down to 60 when ever it felt like it. So last week I went to Audi n bought a genuine one and since than it has worked well. Never dropped in the middle of a drive plusnit only takes 7-10km to reach 90 degrees now during the summer.

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Yes, I buy many things from eBay and often parts for the A2 but I would never buy a temperature sender from there. It controls the running of the engine as well as the temperature gauge and so it can be false economy to buy a cheap one.

Steve B

Birchall said:

Yes, I buy many things from eBay and often parts for the A2 but I would never buy a temperature sender from there. It controls the running of the engine as well as the temperature gauge and so it can be false economy to buy a cheap one.

Steve B

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Agreed. I learned the "hard" way. Sure I saved a lot buying of ebay but will never buy temp. sensor again from another brand other than AUDIs.

Greetings. Temperature sensor replacement, A2 FSI 1.6, 03 plate. Following the advice on this and similar posts, bought the Audi replacement plus O ring, circa £40, but they didn't have the clip in stock, and was advised to use the one already on the car. Everything went fine - until replacing the clip. It is metal (spring steel), and resists all attempts to go in, the problem being access, prevented by a right-angle pipe bolted the the block (two torkx, between 50 and 55). I've placed a guide below the clip slot (nearest to engine side), to prevent that side of the clip going below the slot, which it seems determined to do. Still refuses. (The thoughts, 1: It came out, so it's gotta go back in; 2: which moron designed this?; don't seem to help much.) I see from a look down the ebay versions that all their clips are plastic - are they easy/easier to get in? Are they flexible, a bit? Would the Audi replacement be plastic? (It's Sunday, of course, so I can't check with them, or order a replacement.) Can I put the clip in from the reverse side - it seems it would be easier to do that. I'm tempted to grind off a few mill from the leg ends, which aren't functional - the shorter length might just make insertion possible. (I could remove the two torkx bolts, when access would be a doddle, but I'd have to buy the torkx socket and gasket, so that seems least attractive solution.) Any advice welcome.

You need to press the sensor in a little while pushing in the clip.
But all of the ones I have seen have been plastic.

Also make sure you have removed the old o ring (an easy mistake to make. )

The design means that it can go in from the other side if you have the room but if you have removed the old o ring and are pressing the sensor in a little while doing it (not easy with so little room) it should go in ok.

Steve B

Hi. The old O ring came out with the old sensor. Location of new sensor plus new O ring is fine: the slots the clip should - but won't - slide into reveal the green plastic housing body, not the gold coloured metal of the sensor end, so the sensor is sitting correctly and all it needs is the two clip legs to slide into the two slots - prevented by the pipe plus two torkx bolts. Cheers. (Anyone want a near immaculate silver FSI Sport, 56K, for a tenner?)

Then are you sure you have the right clip? I expect you will answer that with "it is the clip that held the old one in" in which case I would be stumped.

All I can say is that when I tried this for the first time I struggled a little. The main reason was that I didn't have enough room to get the clip absolutely straight and centred.

I would also order a new clip from Audi, because with all of this struggling you may need one.

Sorry, not sure what I can suggest to help (other than offer you twice your asking price for the car - £20?)

Glad to see you still have a sense of humour after all of this hassle.

Steve B

Hi. Following your remark about the reverse fit, I checked to ensure that the grooves went straight through so that the clip would fit from either end, and so fitted it reverse-wise -ten seconds (as opposed to an embarrassing number of hours trying to refit from the side it came out from). I can see both clip legs are sitting where they should and that the clip should still be removable from the front, using an appropriate driver to push the legs backwards. Removal from the reverse side should be possible too. So there you go. Thanks for the help/encouragement. I'm off to test for leaks, restored temp.gauge operation, etc. (Price is once again market value, but thanks for the offer - which at the time seemed a tad too generous.)

Great news.

And I am loving the sense of humour.

Have fun

Steve B