S3 coolant temp?

Damo S

Registered User
Does anyone know what the normal running temperature of the coolant is meant to be? I always though it was about 90C but perhaps these modern cars are different.

Lack of temp gauge is most annoying, and I believe my recent running problem may be coolant temp related i.e. the rad thermostat is stuck open so the engine is not staying at running temperature when the car isnt under load.

During a test drive today my mates OBD reader and phone app said ECT (Engine coolant temp?) was consistently about 102, 103 degrees when not under load (cruising at 45mph in 6th) , but it then dropped to 90 when I gave it some welly. That sounds more like the engine oil temperature to me. I'm sure I read somewhere that the oil temp is maintained at around 102C in normal driving, and 89 when booting it. I wonder if his app is actually reading the wrong value.
 

Svenedin

Registered User
There’s oil temperature and coolant temperature displayed on my S3 (virtual cockpit). Isn’t coolant temperature displayed even without VC? My oil temperature is usually between 102-110 and coolant about 90.
 

Damo S

Registered User
That's good to know. I reckon the reader was showing oil temp as otherwise I would have thought my car would be over heating.

The oil temp shows up on the lap timer page but I havent seen a coolant temp yet. I might have another dig but Im not sure it exists in the DIS
 

RichardT

Registered User
I have coolant temperature guage on my pfl A3 Sport.
 

Svenedin

Registered User
For virtual cockpit:

IMG_2042.jpeg
 

Dannymoto

Registered User
I have S3 without VC and I have coded the oil temp into the main display, cannot see the coolant temp anywhere.

The coolant temp should remain the same, normally 90oC.

The oil temp will change depending on how you're driving, usually rising when driving harder.

So the opposite of what you stated (102oC & 89oC)
 

Svenedin

Registered User

Damo S

Registered User
Thanks. good info guys. Its all pointing to some problem in the engine cooling system but I'm not sure what yet. Im taking it to the local garage tomorrow to put it on their vagcom system to see if they can help work it out.
Fundamentally it looks like it will have to go into Audi and be fixed under the extended warranty. I want more evidence first though because I dont want them handing it back and saying "no its fine" because they couldn't replicate the intermittent poor performance problem (which is definitely ambient temp related, and load related, so not that easy to make happen)
 

ZipZap01

Registered User
Engine coolant temperature is usually around 102-108, going down to about 85-90 during hard acceleration. This is normal and due to the electronic thermostatic control system.

There is no coolant temperature display unless you have VC, but even with VC, the display is "massaged" so that it doesn't show the fluctuations. An OBD-II reader should give an accurate display of coolant temperature.
 

Lau Chun Pong

Registered User
I had installed a "Pivot" gauge and connected to OBD, the coolant temperature is usually around 105-108, going down to about 89-95 during hard acceleration.
 

RichardT

Registered User
..................
There is no coolant temperature display unless you have VC..............
But as I mentioned previously, my pfl “standard” A3 has coolant temperature display.
 

RichardT

Registered User
Why do you need more than an indication of whether the engine is overheating?
 

ZipZap01

Registered User
But as I mentioned previously, my pfl “standard” A3 has coolant temperature display.

Sorry, thread title said S3. Temperature display is deleted on the S3. The A3 does have temperature display (though, it is processed and not the actual temperature).
 

Damo S

Registered User
Engine coolant temperature is usually around 102-108, going down to about 85-90 during hard acceleration. This is normal and due to the electronic thermostatic control system.

There is no coolant temperature display unless you have VC, but even with VC, the display is "massaged" so that it doesn't show the fluctuations. An OBD-II reader should give an accurate display of coolant temperature.

OK, So this is exactly what I'm seeing. Doesnt explain why when poodling along at 40mph on 6th for a while it then starts running badly (holding back boost) until I give it a bit of a caining.

Another twist in the story too. I was in bad traffic for some time in London yesterday and after a while it decided to cut boost completely. Literally had nothing. I crawled to my destination, and then later on when returnign home the car was fine. I'm assuming it had overheated and went into protect mode but I never heard the radiator fans come on at any point (perhaps they are silent).
Its all very weird. the car runs better when its warmer which you would have thought would exacerbate the overheating problem not cure it.
 

RichardT

Registered User
Yes. I was responding to the statement that a temp guage is only available with VC.
Just pointing out that this does not apply to all A3 models.
It appears that only the S3 doesn’t have the temp display.
 

Abzz

Registered User
OK, So this is exactly what I'm seeing. Doesnt explain why when poodling along at 40mph on 6th for a while it then starts running badly (holding back boost) until I give it a bit of a caining.

Another twist in the story too. I was in bad traffic for some time in London yesterday and after a while it decided to cut boost completely. Literally had nothing. I crawled to my destination, and then later on when returnign home the car was fine. I'm assuming it had overheated and went into protect mode but I never heard the radiator fans come on at any point (perhaps they are silent).
Its all very weird. the car runs better when its warmer which you would have thought would exacerbate the overheating problem not cure it.

The fans cut in on mine if in heavy traffic even in this temp, so could the fans not cutting in be the problem with yours?
 

Damo S

Registered User
Its moved on from this since using I bought and have been using torque pro on the car. The boosting problem seems to be due to misfires in cylinder 1 rather than overheating or it running cold.
 

desertstorm

Moderator
Staff member
Moderator
VCDS Map User
More likely to be a coil pack or spark plug issue. Temperature gauges in VAG cars have been pretty much indication only type gauges since they started putting electronic gauges in the cars in the late 90's. On most cars anywhere between about 75 degrees and 100 degrees is assumed as "normal" and the gauge will sit at 90 degrees. The trend these days is to have the engine running hotter than what used to be assumed normal as this improves fuel economy/ emissions etc. When you get on it, the electronic stat will alter the running temperature to where it needs to be for the best performance.
 

Damo S

Registered User
yes, Torque reports a normal temp of about 103, 104C dropping down to 90C when under load. That seems to be consistent.
It may also be the injector. one of the 3 (injector, plug or coil pack). Hopefully its just the plug, although I just hope a few months of misfires hasnt damaged the piston.
 
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