1.4 Petrol Thermostat location / guide to fix?

P12MOO

Member
Hi all,

Hope you can help.

Off and on for the past few months we have had problems starting the A2 (1.4 petrol) and also the fans in the car have felt weak.

Had some time to look into the problems last weekend and to resolve the fans problem I removed the glove box and took out the cabin filter to order a replacement. (Fans worked great with a test without cabin filter fitted but advised my wife not to use them)

At the same time I also removed the fuel relay, cleaned up the spade connectors and refitted.

All seemed fine, jobs ticked off. Except, during the week the car started to run funny / over revving / starting playing up again / engine light on / etc.

Engine light had gone back off by Monday and my wife was using the fans as it was a hot day (without a cabin filter in) suddenly all but one fan goes off completely.

Monday night I bought a OBD scanner off the bay of e, arrived today, very handy for £25 - don't know how i've coped before.

Anyway I've got a 16502 - Engine coolant Temp circuit - High Input error.

Searched around the site and it seems to be the thermostat that needs replacing and that it's fiddly to get to.

Trouble is I can't seem to find any online guides with photos on how to replace it. Can someone point me in the right direction please to a guide and also the correct part needed?

I'm hoping that the fans problem is connected - is the car confused about the temperature and putting all it's efforts in the engine instead of the occupants?

In other news, got the wheels powdercoated in gloss black today so she looks great even if she doesn't run great. :D

Thanks in advance.
Phil
 
16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High

Possible Symptoms
Difficulties with starting a cold engine.
Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
RPM at idle is irregular.
With all engine temperatures idle rpm will often vary between 900 - 1000 rpm.
With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
Bad acceleration during warm-up.
Diesel Engines: Glow plug indicator may be on for a longer than normal time or at ambient temperatures where it shouldn't come on at all.

Possible Causes
The electrical signal coming from G62 is too low
Wiring and/or connections faulty (short circuit?)
Engine Coolant Temperature Sensor (G62) faulty

Possible Solutions
Check wiring and connections
Check / Replace Engine Coolant Temperature Sensor (G62)



In many cars between MY 1995-2002 the G2/G62 had a bad reputation for failing often. The original G2/G62 sensor is black and the improved replacements are green!



Cheers
Sarge
 

Attachments

  • Unplugging connector at coolant temperature gauge sender -G2 -G62- - vehicles with 1.4 l MPI eng.pdf
    176.2 KB · Views: 1,321
  • Removing and installing coolant temperature sender -G62-.pdf
    412.6 KB · Views: 1,449
Brilliant, thanks Sarge.

Is G2 just the sender for the temperature gauge as that has stayed at the usual 12 o'clock position the whole time.

I think only G62 needs replacing based on the problems experienced or does it make sense to replace both at the same time while you're at it?
 
The G62 sensor is a 'dual' sender, it sends signal to the Temp gauge in your clocks and also sends signal to the ecu, one side or the other usually fails, I have the temp gauge in the locks side fail.

You will need to top up coolant when doing this and is it a fiddly job. The replacement will be a green one and the one in your car usually will be a black one. The green is supposed to be a upgraded part, but I have replaced both coloured ones in cars before.
Also you will be supplied a plastic clip to fix it in position, the one on the car will be a metal one.


Cheers
Sarge
 
Sorry for resurrecting old post, but I probably have to replace the Thermostat sensor as well as Temp Gauge goes between 70-90C, and I assume it should sit bang on 90C.

With the documents above shouldn't be much issue changing it.
Bte Thermostat and Thermostat Sensor the same? Don't you have to remove cambelt to access/change the Thermostat?
 
Can anyone attach a link of which Thermostat Sensor replacement is good for 1.4 petrol? There's a lot on eBay and Eurocarpark got few as well. Thanks
 
Here is a picture from the manual


It is best to fit OEM for the thermostat (coolant regulator) and temp (coolant) senor. Make sure those advertised refer to the OEM numbers or ask if @CreweAudi can supply the parts to you.

Also make sure you get the correct thermostat as the 2 listed open at different temperatures.
 
Are you talking about the thermostat or the temperature sensor?
It's the thermostat sensor. The temp gauge going 70-90C. The manual doesn't load to me, and not sure what the difference between the 2 types. How to find out which one I need without removing the sensor first? Thanks
 
Again not sure you have your terminology correct. The thermostat or coolant regulator is a mechanical valve that sits in the pipe and opens at a set temperature ( or 2 different ones in this case ), the temperature sensor has electrical lead on it and senses the coolant temperature. Your problem could be either indeed it could be both are faulty. Personally I would change both and then top up with the correct premixed (diluted) coolant.
 
Again not sure you have your terminology correct. The thermostat or coolant regulator is a mechanical valve that sits in the pipe and opens at a set temperature ( or 2 different ones in this case ), the temperature sensor has electrical lead on it and senses the coolant temperature. Your problem could be either indeed it could be both are faulty. Personally I would change both and then top up with the correct premixed (diluted) coolant.
I've done some research on the website and I've come to a conclusion it's definitely thermostat/sensor related, I just want to try the sensor first, as what I've read, to change the thermostat itself involving removing the cambelt, which I plan to do next year. Plus it's not an asap issue hopefully, as been like this for at least 1.5 year since I bought the A2 and no other issues/EML has come on since, MPG isn't bad either.

So I just need to know which one to buy, I think it's called G62, hence I've asked for a thermostat sensor recommendation/link. Thanks
 
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I agree it is thermostat / sensor related. Unfortunately the link I posted to the manuals does not appear to be working. If it were me I would replace the thermostat and the sensor at the same time and would also seriously consider replacing the plastic housing they sit in as the plastic by now will be very brittle. Changing the thermostat itself involving removing the cambelt not needed as they are on the right of the engine and the cam is on the left as you look at the engine.
Here are the manual pages for both


 
Hi @Sylvester,

Sorry I do not have a 1.4 petrol and cannot help specifically, but it might make matters easier for you if you order the thermostat and coolant temperature sensor (G62) through Crewe Audi here on the forum. Send Crewe Audi a PM, request the parts and supply your registration number, that way your parts will be guaranteed to match your car perfectly. It will cost a lot more but you will have peace of mind.

Andy
 
Hi @Sylvester,

Sorry I do not have a 1.4 petrol and cannot help specifically, but it might make matters easier for you if you order the thermostat and coolant temperature sensor (G62) through Crewe Audi here on the forum. Send Crewe Audi a PM, request the parts and supply your registration number, that way your parts will be guaranteed to match your car perfectly. It will cost a lot more but you will have peace of mind.

Andy
Okay I'll send them an PM, cheers Andy.
 
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