Engine Temperature

miikeeyy92 · 7 Apr 2014 at 10:20

Okay, so I bought an A3 on friday, after having a run around in it, and the temperature was rising fine when I test drove it. Admittedly I wasn't in it long enough for it to rise all the way, but it was on its way so I presumed all was fine.

On the way home, instead of sitting at 90 degrees, it stuck at 70. I can't remember if that was with the AC on or not.

Ive been keeping an eye on it all weekend, and I can't suss it out. The temperature rises to 90 after a while, but it seems to pause at 70ish, this is with the AC not on.

I had noticed the fans came on when I started it up at one point.

Initially I thought the thermostat was broken, but I'm not sure?

Any thoughts?

acemastr · 7 Apr 2014 at 10:23

I'd say thermostat

miikeeyy92 · 7 Apr 2014 at 10:25

Are there any other possibilities?

Dr Who · 7 Apr 2014 at 10:25

Yeah, it's a bit cold out, might be a thermostat sticking open slightly. See how it goes and if the fuel economy is bad, if so get it changed.

miikeeyy92 · 7 Apr 2014 at 10:28

Is it something that will flag up when plugging into a computer?

leigh_boy · 7 Apr 2014 at 10:57

not likley to show up on a diagnostics as its mechanical with no sensors only way to test it is to take it out and put it in some hot water on the temp it should open at and see what happanes. they are not normaly expensive items to replace.

miikeeyy92 · 7 Apr 2014 at 10:58

leigh_boy said:
not likley to show up on a diagnostics as its mechanical with no sensors only way to test it is to take it out and put it in some hot water on the temp it should open at and see what happanes. they are not normaly expensive items to replace.

Okay thanks. Ive been quoted £189+VAT for parts and labour. its a 2hr+ job apparently. Just got to make sure the dealer takes the cost as it is under warranty

miniyazz · 7 Apr 2014 at 18:50

Sounds steep, I had the thermostat replaced on my Golf for £40 inc parts and labour

How long does it take to reach 90ºC? TBH though you'll almost certainly know it's the thermostat if you a) start the car and let it warm up to 90ºC
b) take it for a drive along an A road or motorway 50-65mph for 15-30mins
if it cools down along the motorway to 70 that would pretty much confirm it for me. If not.. might not be broken.

telewebby · 7 Apr 2014 at 18:57

coolant temp sender, 10min job need the sender the clip and a 1l bottle of coolant

Alex

MORE SPEED · 7 Apr 2014 at 19:33

Cheers for this, certain that it's what's up with my car as well now

miikeeyy92 · 7 Apr 2014 at 19:37

miniyazz said:
Sounds steep, I had the thermostat replaced on my Golf for £40 inc parts and labour

How long does it take to reach 90ºC? TBH though you'll almost certainly know it's the thermostat if you a) start the car and let it warm up to 90ºC
b) take it for a drive along an A road or motorway 50-65mph for 15-30mins
if it cools down along the motorway to 70 that would pretty much confirm it for me. If not.. might not be broken.

Hmm, sounds a lot cheaper for you. Breakdown for me was 2.7hrs @ £55/hour labour, £13 for some coolant, £28.76+VAT for thermostat.

I've looked online and everyone says at least 2hrs+. Its a very good local garage that we've always been too so I don't mind paying a bit more for labour.

The car reaches 90 degrees when not moving, as it would as the fans aren't spinning, and then it decreases when on the move.

Jono8 · 7 Apr 2014 at 19:43

Sounds like the thermostat to me. Ignore the guy who said he got it done for £40 inc parts and labour as that is clearly mates rates and honestly only would cover the cost of the stat + coolant (and not labour) so it is not very helpful to you.

1st rule of car threads - someone has always bought the same car loads cheaper or had the same job done on their car loads cheaper than you

86JR · 7 Apr 2014 at 19:53

Which A3 is it?

miniyazz · 7 Apr 2014 at 20:32

Jono8 said:
Sounds like the thermostat to me. Ignore the guy who said he got it done for £40 inc parts and labour as that is clearly mates rates and honestly only would cover the cost of the stat + coolant (and not labour) so it is not very helpful to you.

1st rule of car threads - someone has always bought the same car loads cheaper or had the same job done on their car loads cheaper than you

Not mates rates, I'd only been there about twice before for MOTs. However that was what they charged and I didn't ask for a breakdown..
Was rather surprised though since most of that cost had to be the part!

Dangerous Dave · 7 Apr 2014 at 20:41

As above what model of A3 is it ? and does it have a DSG box ? Depending on engine/gearbox they can have three thermostats.

If you have access to VAGCOM/VCDS the coolant system has several coolant sensors which allow you to check at what temperature the main thermostat is opening.

( |-| |2 ][ $ · 7 Apr 2014 at 20:41

telewebby said:
coolant temp sender, 10min job need the sender the clip and a 1l bottle of coolant

Alex

I changed the CTS on my Leon 1.8T this weekend, there was absolutely no need to change the clip and if you do it with a fully cold engine there's no coolant loss.

Well, at least that was my experience. (turns out it wasn't the cause of my problems)

miikeeyy92 · 7 Apr 2014 at 21:23

Dangerous Dave said:
As above what model of A3 is it ? and does it have a DSG box ? Depending on engine/gearbox they can have three thermostats.

If you have access to VAGCOM/VCDS the coolant system has several coolant sensors which allow you to check at what temperature the main thermostat is opening.

It's an 06 2.0T FSI. I've done a bit of research and there has been loads of threads where they have plugged into a VAGCOM, it's returned a temp sensor error which hasn't fixed things, but replacing the thermostat has.

Dangerous Dave · 7 Apr 2014 at 21:52

miikeeyy92 said:
It's an 06 2.0T FSI. I've done a bit of research and there has been loads of threads where they have plugged into a VAGCOM, it's returned a temp sensor error which hasn't fixed things, but replacing the thermostat has.

You are in the cut over year for the engine codes if you have the newer BWA engine it only has a main thermostat and one for the DSG box if fitted, the earlier AXX engines have an additional thermostat for the cooling to the turbo. You are better to replace all the thermostats at the same time as a lot of garages don't realise some models have additional thermostats and wonder why either the fault returns quickly or not fully resolved once the main thermostat is replaced.

The temp sensor error will be likely caused by the user selecting the wrong sensors, used correctly you can see the temperature the thermostat starts to open which should be around 80c.

It is a common fault for them to start to open early causing the engine to be overcooled, I just had to replace mine after it started opening at around 70c. It is not a small job to replace as the alternator needs to come off to get to it along with boost and coolant pipes.

Jono8 · 7 Apr 2014 at 22:37

miikeeyy92 said:
It's an 06 2.0T FSI. I've done a bit of research and there has been loads of threads where they have plugged into a VAGCOM, it's returned a temp sensor error which hasn't fixed things, but replacing the thermostat has.

My 06 Octy VRS with that same engine needed it done last year. The needle would drop below 90 indicated going down a hill or coasting slowly/partially off throttle. I checked the climatronic display for the actual coolant temp and it was only barely getting to 75 degress ( still showed as 90 on the gauge). As soon as it dropped a few degrees though the needle started to fall. I had the thermostat replaced and all has been fine since. Warms up in a decent amount of time and the climatronic reading shows it running at 90-96 degrees always now (needle never moves once warmed up either).

It isn't an easy job though as the alternator needs to come off. My local specialist did it for 2 hours labour cash. I supplied the part and coolant (bought genuine from a main dealer on ebay).

miikeeyy92 · 8 Apr 2014 at 09:39

Dangerous Dave said:
You are in the cut over year for the engine codes if you have the newer BWA engine it only has a main thermostat and one for the DSG box if fitted, the earlier AXX engines have an additional thermostat for the cooling to the turbo. You are better to replace all the thermostats at the same time as a lot of garages don't realise some models have additional thermostats and wonder why either the fault returns quickly or not fully resolved once the main thermostat is replaced.

The temp sensor error will be likely caused by the user selecting the wrong sensors, used correctly you can see the temperature the thermostat starts to open which should be around 80c.

It is a common fault for them to start to open early causing the engine to be overcooled, I just had to replace mine after it started opening at around 70c. It is not a small job to replace as the alternator needs to come off to get to it along with boost and coolant pipes.

Thanks for your input, after a quick bit of research, its a BWA engine, and no DSG box so i've only got the 1 thermostat. I would have attempted it myself if it didn't sound so tricky to get to the thermostat. Booked in for tomorrow so hopefully we will be sorted.