MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: its_neil on January 20, 2014, 03:56:05 pm
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Hi guys,
My car for some reason seems unable to sit at 12 o'clock on the temperature gauge, it never goes above 12 o'clock (90 degrees) but just slowly fluctuates between about 70 and 90. I know that although the car isn't overheating that this behaviour isn't right but what could be causing it? Could it be the thermostat?
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Yes, or coolant temp sensor.
I changed the coolant sensor and it is still doing exactly the same as you describe.
I am changing the thermostat next.
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For the sake of about £25, I would change the sensor first. It is way easier to do than the thermostat and only takes a minute or two. And you don't have to drain the coolant.
The main thermostat is slightly different, you need to remove the alternator for easy access and was a bit of a pain to do.
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Mine started doing this at the weekend.
Anyone have coolant temp sensor part number?
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Mine started doing this at the weekend.
Anyone have coolant temp sensor part number?
Look here
http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1728&ein=2007&f=474&hauptgr=1234567890&hg=9&grf=091940249&bf=91940&hgug=919&ug=19&parent_id=2361269
06A 919 501 A - £38.62 inc vat full retail - 2 pin black 20 mm
N903 168 01 O-ring Seal - £0.54
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Bet you a million pounds it's the main thermostat. Your car has 2. Or 3 if it's a dsg. The 2 small ones are inline. The main thermostat will cause the temp issues. To help diagnose it. Does the car temp get higher towards 90 when in traffic then drop when you drive.
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Bet you a million pounds it's the main thermostat. Your car has 2. Or 3 if it's a dsg. The 2 small ones are inline. The main thermostat will cause the temp issues. To help diagnose it. Does the car temp get higher towards 90 when in traffic then drop when you drive.
Attach a link of your thread - you'll be helping them a great deal :happy2:
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This is one of the links. Will try and find others. Worth a read of them all to diagnose your issue
http://www.mk5golfgti.co.uk/forum/index.php/topic,77085.0.html
Have a look through this too. There a few links to other threads. I found the more I read of others with similar problems helped my pinpoint the problem with mine. Mine turned out to be the two inline thermostats. As the car took ages to warm up. Now they are swapped its warm to 90 in 2-3 miles max. Even in this wether.
http://www.mk5golfgti.co.uk/forum/index.php/topic,76566.0.html
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Cheers guys,
Mine is a 2005 with DSG and yes, it goes up and drops when you start to drive a bit faster (i.e so if you've been queueing in town it'll sit about 90 but as soon as you speed up onto the motorway it drops)
Would this have any effect on the car? I.e MPG and whatnot?
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Cheers guys,
Mine is a 2005 with DSG and yes, it goes up and drops when you start to drive a bit faster (i.e so if you've been queueing in town it'll sit about 90 but as soon as you speed up onto the motorway it drops)
Would this have any effect on the car? I.e MPG and whatnot?
mines a 2005 with DSG and I am having mine changed saturday it does exactly the same. 90 in standstill and 70 when you are driving.
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Cheers guys,
Mine is a 2005 with DSG and yes, it goes up and drops when you start to drive a bit faster (i.e so if you've been queueing in town it'll sit about 90 but as soon as you speed up onto the motorway it drops)
Would this have any effect on the car? I.e MPG and whatnot?
I had the main stat changed a few months ago - up to temp in about 3-4 miles in this cold weather. It never really got up to 90 before, except on motorways.
MPG improved by about 2. Performance seemed better as well. My understanding is the ECU holds back power until the engine is at the right temp. Therefore if its not up to temp not all the power is available.
The job is long and a bit fiddly - VW book time is 3 hrs!
When the weather gets better I'm going to change the 2 smaller inline stats as well. This speeds warm up time as well.
What crap designs they must be! I can't remember changing a stat in the last 25 years! A few in 'the old days' though.....
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Loads of cars suffer crap stats now. Had to have the main and egr ones done on my BM :(
Is there a how to anywhere for those 2 regulator replacement? VW changed the main stat but refused to do the smaller 2..........
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Loads of cars suffer crap stats now. Had to have the main and egr ones done on my BM :(
Is there a how to anywhere for those 2 regulator replacement? VW changed the main stat but refused to do the smaller 2..........
Yes there's loads on it here, especially recently. Have just tried to find it but the search wont work!
Have a go yourself. I'll try again in while
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There was a thread on here a month or two ago by itguy, it was a very good one. It won't sort your fluctuation problem though. The thread is for the inline regulator/s. If you have DSG you will have two inline regulators, if you have a manual, there is only the one.
These only effect the length of time the car take to warm up, if you car takes ages to warm up in cold weather, one or both of these are to blame. Your fluctuation is caused by a knackered main thermostat which is attached to the block. I have had both problem, now both are sorted :jumpmove: thank god!
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As above. The link I posted was for the two inline stats. I know you said yours does not maintain temp but if it takes more than 3 miles to get warm it will be the inline stats as well as the main stat. If that's the case let me know and I can put a guide up for those.
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Its not a complete how to though unless I'm reading it wrong? I quite up for home mechanics but I do like a nice step by step lol :evilgrin:
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Fair point mate. Give us a couple of hours and I will get a how to for the inline stats with a few photos. Also will cover a really easy way to drop the coolant out.
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Nice one fella cheers :notworthy:
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Sorry for delay. Something went wrong after I posted that and I have not been able to get on the forum for a few days will sort it tonight.
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Would be interested in seeing this guide too, as I think my inline stat needs doing as well!
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All done. Link is here
http://www.mk5golfgti.co.uk/forum/index.php/topic,78341.msg817626.html#msg817626
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You are a star chap! :happy2:
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Almost certainly the thermostat!
Vag com engine mvb 1 check that the temp it reads is the same as on dash!
If it is then deffo thermostat!
Mine is doing it to :/ gotta have the front end off soon to do the ac so gonna change it then!
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That link is a guide for the online thermostats not the main stat. Was planning on changing that next if the problem was not cured. But mine is now fine so did not go down that route.
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^^^^ Nice guide :happy2: Still think I might not risk it myself though, probably cause a more serious problem in the process! :laugh: I'll see if my indy can do it when they change my radiator. They will have to drain the coolant for that anyway and maybe they can get to the stat easier whilst they have the radiator out.
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I had same problem , 70 all the time instead of 90 so was going to get the thermostat done today but the guy who was doing it for me along with the cambelt and water pump was given the wrong part so he just did the cambelt and water pump . I was pretty annoyed but funny enough he said my belt wasn't too bad but my water pump was leaking. I thought maybe I don't need the thermostat after all and hey presto I don't , it goes straight to 90 so never needed one in first place . Charged me 260 quid fitted so good price . :happy2:
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I had same problem , 70 all the time instead of 90 so was going to get the thermostat done today but the guy who was doing it for me along with the cambelt and water pump was given the wrong part so he just did the cambelt and water pump . I was pretty annoyed but funny enough he said my belt wasn't too bad but my water pump was leaking. I thought maybe I don't need the thermostat after all and hey presto I don't , it goes straight to 90 so never needed one in first place . Charged me 260 quid fitted so good price . :happy2:
Just curious to know if you we having to top-up your coolant regularly? Just for diagnostic purposes :popcornsoda:
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I had same problem , 70 all the time instead of 90 so was going to get the thermostat done today but the guy who was doing it for me along with the cambelt and water pump was given the wrong part so he just did the cambelt and water pump . I was pretty annoyed but funny enough he said my belt wasn't too bad but my water pump was leaking. I thought maybe I don't need the thermostat after all and hey presto I don't , it goes straight to 90 so never needed one in first place . Charged me 260 quid fitted so good price . :happy2:
Just curious to know if you we having to top-up your coolant regularly? Just for diagnostic purposes :popcornsoda:
I have never looked , I leave that sort of stuff to mechanics
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any1 got the part number for the main stat ??
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any1 got the part number for the main stat ??
Probably need to check with main dealer as there are two varieties. One is just the thermostat and the other is the complete housing with the thermostat enclosed.
Mines a 05 AXX an need full housing which was part number:
06F 121 111 F @ £33.91 from local dealers
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any1 got the part number for the main stat ??
Probably need to check with main dealer as there are two varieties. One is just the thermostat and the other is the complete housing with the thermostat enclosed.
Mines a 05 AXX an need full housing which was part number:
06F 121 111 F @ £33.91 from local dealers
thanks varley ill pop dwn there 2moz n find out
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That's correct for both BWA - BPY engines
That's the link to the online parts catalogue:-
http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1731&ein=2008&f=625&hauptgr=1234567890&hg=1&grf=012175420&bf=12175&hgug=121&ug=21&parent_id=2850753&detail_id=2850756
Price quoted is still current and is full retail inc vat.
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I have a question that one of you wizards may be able to answer...
My temp gauge was fluctuating, well more like dropping rather than fluctuating but anyway.. as I was saying.. I've never known it drop whilst driving.. It's only when I put my heaters on and I only put them on when the car is at 12 o'clock on the temp gauge. Now as soon as I knock my heaters off, it climbs back up to 90 again.
I should also mention that I've had a main stat fitted thinking that this was the problem but the problem still remains.
I know there is other culprits to look at such as inline thermostat, coolant temp sensor, coolant temp sender? I think it's called and then the dreaded water pump which if it helps.. This was replaced the same time as belts etc 5-6K miles ago..
I don't want to just have bits replaced for the sake of it but I don't have a clue what the next best thing to do is..
Cheers,
Carl.
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If that was my problem (since you've replaced the main Stat) I would
Check for an air lock
Check the cap seal
Replace the in line regulator (x2 if it's a DSG)
Then if that fails do testes with VCDS ( the senors I've had problem tend to fail so I wouldn't expect your type of fault with a sensor but testes with a multi meter would confirm if the sensor is in spec)
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I've recently had the main stat replaced and temperatures now reach 90 and stay constant, however it does seem to take longer than it should to reach the correct running temp.
With regards to the above post, how would I check for any air lock? If there is one, how would I remove it?
Thanks hopefully in advance :)
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^^^^^ Testes :grin:
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I have a BWA engined GTI seems to have problem ,the temp gauge does reach 90 but when it does it can fluctuate when driving between 70/90.
when driving to work however 4-/5 miles it rarely reaches 90 more like 70 .
I purchased the car from VW 10 months ago and I still have some warranty left would this be covered if I needed a thermostat etc .
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I have changed the main stat and both sensors and still it goes up and down zero ...to the top warning light comes on no over heating to coolant loss changed water pump even put a radiator flush in