Engine Coolant Sensor

[TonyMc]

My car has had a history of idling low when started and stalling when at junctions until warmed up. I have also noticed the coolant temp guage gives a low reading, should be on about 90 degrees I believe but suggests about 45 degrees. My mate put his VAG on it ;-) and a reading for the coolant sensor came up and nothing for the MAF. So I can only assume that the sensor needs changing.

So 3 questions;

1 How much are they?

2.Where is the cheapest place to source one from.

3. Is it a skilled mechanics job or can an amateur attempt to change it.

4. If I went to VW, how much would they charge?

I know that's 4 questions.

Any help would be appreciated.

[vince70]

They are cheap as chips, about £8 from german and swedish or euro car parts, its a five minute job to fit just take the old one out and put the new one in, you dont even need any tools as its just a pull out clip, just make sure you leave the car over night before putting the new one in otherwise you will end up with hot water everywhere.

It might be worth buying a 1.5 litre bottle of antifreeze while your at it, but make sure you buy the VW/Audi G12 antifreeze which is also about a fiver, as you can't mix standard antifreeze with the VW stuff.

[TonyMc]

Ok I have bought the sensor which the blokey at Euro Car Parts assures me is an easy job. Well it would be if I new where to find it under the bonnet.

Can anyone point me in the right place. I have a 1999 1.8 petrol model, I believe its a ADR engine.

Thanks in advance..

[portovechios]

Its on the engine block/housing with a black cap and 4 wires into it, it will have a black c clip holding it in place, normally at the backish

Don't know your engine so cant confirm were but its a doddle as long as the engine is cold and you retop what you lose

Good mpg and idling should resume because the cts will communicate with ecu and fuel map
correctly

[TonyMc]

Thanks for that. But concerned though as I've just noticed the sensor didn't come with a new o ring. Is it too dodgy with risk of a leak to try and get one from a motorist shop that might fit? Or should I have bought a complete set with sensor, clip and o ring?

[portovechios]

No o ring?

Normally the old ones fine but did you get a new c clip?

[TonyMc]

No just the sensor itself and nothing else

[portovechios]

On the tdi's its green with an o ring and a c clip but perhaprs your is diff being a petrol!?

Have you located it yet?

[TonyMc]

I rang VW and they sell an O ring and clip for a total of £1.80 so panic over there. I had a look at the back and I could see a sensor with 4 little wires going into it just under the air intake pipe that goes to the MAF. Does that sound like the right one?

[TonyMc]

Well I have changed the sensor and as everyone said, it was easy. When I took the old one out it didn't even have an o ring fitted and the sensor terminal was soaked. But now I have more pressing concerns;

I left for work this morning (18 mile journey) and the temp gauge was slightly above halfway between 0 and 90 degrees when I arrived at work. So still dodgy but caused by something else or should I take into account that it was freezing? Next thing is that it still started rough with poor revs and bit of stalling until warm. But the revs settled better at junctions and didn't drop to a ridiculously low level before settling.

The other concern was that I was near the end of my journey down a dual carriageway and I had a short loss of power for about 3 seconds then it kicked in again, but it was fine on the way home. Could it of been that I was already on reserve before leaving and a bit of crap from the bottom of the tank had gone through? I usually keep my tank topped up and this is the lowest its ever been. Or could this all be related to a MAF and/or throttle body issue? I checked the the air pipe when I got home as I removed it to get to the sensor, and it is all fitted properly.

Any ideas anyone?