MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: Numero9 on July 28, 2022, 10:52:37 pm
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Got all the symptoms of a stuck open thermostat so plan to change it this coming weekend however watching a few videos I've confused myself any need some help clarifying a few things
1) is it right that in later GTi (mines 08) there is more in line stat and only the main one to replace?
2) seems to be 2 options remove intake or remove alternative, is there a preferred method from those who have done it themselves?
3) watching one video there was a comment about also changing the o-ring on another pipe but I can't remember which video said it or where the o-ring was, does anybody have a diagram for where and possibly a part number?
I know it'll be a pit.of a.job but I have a full day set aside to oil change, coolant flush and this and quite looking forward to it...
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It all depends on the gearbox you have to my knowledge.
Manuals have one near the alternator. This is for the Turbo and prone to failing like mine did, as it stuck open and never go to temperature...........fine now.
The second/additional one is for people who have DSG, and that sits above the box and works for the box
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Sorry should have said its a manual 08. From what I read the DSG and 3 and the manual has 2 but also ready the inline was deleted so a later GTi should only have 1
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Have a look in the engine bay to determine it for yourself. As stated, the thermostat count varies with model year and gearbox type. My manual 07 has 1 thermostat.
Removing the alternator is the best method. It's dead easy once that is out of the way.
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The whole "3 thermostat" thing was just on early cars - as Pudding said - check how many inline ones you have -if any. not cheap, over £40 each a few years ago. As an example my 2006 DSG has a single inline.
If you are changing the main thermostat, consider doing the coolant temperature sensor at the same time, as it is mounted within the thermostat housing - sods-law guarantees it to fail within 6 months if you don't change it!
Alternator off is the best way forward, but tight if you have large hands, making the whole job awkward - I have not seen inlet manifold off as a suggested route - it would be a $ite ton more work and has the potential to create more problems.
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New thermostat and sensor ordered. Are there any other o-rings or bits that I should replace along the way?
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New thermostat and sensor ordered. Are there any other o-rings or bits that I should replace along the way?
(https://i.postimg.cc/T3w7MBLb/cooling-system.jpg) (https://postimages.org/)
I had a coolant leak from the o-ring on the main thermostat (marked 5 on this diagram), the part number for it N90365302, might be worth replacing while you're in there :happy2:
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The specialist I use changes thermostats by removing the inlet manifold as he says it is the easiest and quickest way, he has done 100's so take what he considers easy with a pinch of salt.
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I'm going to go down the alternator removal route with this. Seen a few videos on that way and have had prior experience on my other car on removing the alternator and getting it back it.
@OllieVRS (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=102740) - where did you get that parts diagram from?
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I'm going to go down the alternator removal route with this. Seen a few videos on that way and have had prior experience on my other car on removing the alternator and getting it back it.
@OllieVRS (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=102740) - where did you get that parts diagram from?
I think off of Google images, I pulled this image off one of my older threads when I was investigating my coolant leak. Also to clarify since there are multiple rings marked 5, it's the one with the red arrow.
I've found a similar diagram which is even better detailed: https://workshop-manuals.com/skoda/octavia-mk2/drive_unit/2.0/110;_147_kw_fsi_engine/engine_cooling/parts_of_cooling_system_summaries_of_components_engine_identification_character_bwa/parts_of_cooling_system_engine_side/
The O-Ring I'm talking about is marked 9 on this one, directly below the 26.
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Collect all the parts tomorrow & fit over the weekend plus an oil change.
Any other tips or guidance would be much appreciated & thank you all so far!
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Alternator out and a couple of hose clamps to stop/slow the flow of coolant out the system.
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going to drain the coolant, not sure when it was last done and for the sake of few £ rather drain and change it. Definitely going with alternator out method
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I'd also remove the fans if possible. it's tight in there.
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I did this myself a little while back. Alternator route, leaving the fans in place.
Horrible job to do on your back and I actually managed to make a mess of the o-ring which meant that it was compressed in the wrong position. That had the impact of backing out the bolts. I ended up giving it to a specialist who said that the water pump was also leaking. £750 for refitting the thermostat, doing a cambelt and water pump.
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I'd also remove the fans if possible. it's tight in there.
Definitely.
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Fans removed from the top or bottom? On the family wagon, 3 fixings, unclip a hose and connector & it's out.
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Another joy of dealing with the stealers, I think I may have to try another one as this one doesn't seem to get anything right. Was told when ordering the thermostat it would come with the sensor. Just got home and opened up the delivery box and no sensor.
The sensor is one into the hose and with a clip, is this the same one as the pics don't show a clip or o-ring in it:
https://www.eurocarparts.com/p/era-coolant-temperature-sensor-223440210
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The specialist I use changes thermostats by removing the inlet manifold as he says it is the easiest and quickest way, he has done 100's so take what he considers easy with a pinch of salt.
To be fair there is a YT vid by Naptowntuner taking a TFSI manifold off in something mad like 5 minutes - but don't recall him showing it going back on!
inlet manifold off definitely will make it an easy fix for the thermostat - but I would be concerned about disturbing the teflon injector seals and you have to deal with the support bracket bolt the yanks overdramatically call the the "satan bolt". If your not practiced in inlet removal, I would say leave it alone.
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Another joy of dealing with the stealers, I think I may have to try another one as this one doesn't seem to get anything right. Was told when ordering the thermostat it would come with the sensor. Just got home and opened up the delivery box and no sensor.
The sensor is one into the hose and with a clip, is this the same one as the pics don't show a clip or o-ring in it:
https://www.eurocarparts.com/p/era-coolant-temperature-sensor-223440210
Yes -it doesn't come with sensor. doesn't come with clip or O-ring
That one does look right, but at that price you may as well go genuine
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Another joy of dealing with the stealers, I think I may have to try another one as this one doesn't seem to get anything right. Was told when ordering the thermostat it would come with the sensor. Just got home and opened up the delivery box and no sensor.
The sensor is one into the hose and with a clip, is this the same one as the pics don't show a clip or o-ring in it:
https://www.eurocarparts.com/p/era-coolant-temperature-sensor-223440210
Yes -it doesn't come with sensor. doesn't come with clip or O-ring
That one does look right, but at that price you may as well go genuine
Read genuine is £40+ for sensor, o-ring & clip. Going to the dealer again tomorrow, hopefully they have it otherwise they've cost me a weekend in getting this sorted and not impressed with their level of information, how can they know/not know if the stat has the sensor in
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Read genuine is £40+ for sensor, o-ring & clip. Going to the dealer again tomorrow, hopefully they have it otherwise they've cost me a weekend in getting this sorted and not impressed with their level of information, how can they know/not know if the stat has the sensor in
That's only £13 more than euro one, and genuine is likely to last longer - probably its the original one on the car.
Agreed - its annoying, likely they were thinking of another thermostat, no point sweating it.
Time served mechanics check over parts before leaving the counter - annoying if you are queuing up behind them - but its a good habit to get into, it has saved me a few times at Euros.
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Read genuine is £40+ for sensor, o-ring & clip. Going to the dealer again tomorrow, hopefully they have it otherwise they've cost me a weekend in getting this sorted and not impressed with their level of information, how can they know/not know if the stat has the sensor in
That's only £13 more than euro one, and genuine is likely to last longer - probably its the original one on the car.
Agreed - its annoying, likely they were thinking of another thermostat, no point sweating it.
Time served mechanics check over parts before leaving the counter - annoying if you are queuing up behind them - but its a good habit to get into, it has saved me a few times at Euros.
I think I'm going to get into that routine and check unfortunately I didn't collect these having been away.
Hopefully they have one in stock otherwise it's going to be a right pain in the chops!
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None in stock at the dealer so the one from euro it is, although it has no clip but o-ring so just got to be careful getting it off.
Dealer wanted £60+ for the ECT, o-ring & clip!
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Yes that sensor is expensive and always has been for some reason. It was £45 10 years ago, so hasn't gone up by much really.
Fans come out the bottom the easiest I've found. Just 4 self tappers and it's out. I didn't find that necessary when doing my thermostat though. Just removing the alternator opens up all kinds of real estate.
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All done and dusted and runs up to temp within minutes. Left it over night to check for leaks and top up more coolant.
Took the fans out in the end, only 4 fixings and connector at the bottom made life much easier especially for hand clearance. Had a big issue with disconnecting the bottom radiator hose, couldn't get it free from either end so had to cut the end off the stat and use some serious effort to get the end off. Flushed the hose end to remove any potential swarf that might have gotten in.
Glad I changed the temp sensor too, was quite corroded. FYI the one from ECP was absolutely fine, o-ring was spot on and no damage to the clip meant I reused it. About £50 saved there!
And the tip about the alternator bushes (not sure if it was here, another thread or a video) the deep socked to draw them out slightly meant fitting it back was so easy, had more trouble getting the p-clip back on that fitting the thing...
Appreciate all the help and guidance on this one. Now just oil change and to check for any broken headlight level sensors
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Glad you sorted it
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Glad you sorted it
With guidance from you lot & youtube videos!
I'd love to meet the engineers who decided to put the thermostat there though :thinking:
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Glad you sorted it
With guidance from you lot & youtube videos!
I'd love to meet the engineers who decided to put the thermostat there though :thinking:
German cars are all the same. Plenty of plastic crap in hard to reach places, which they know darn well will go brittle and fall apart. MK7.5 owners with the £500 plastic water pump (very high failure rate) would certainly be jealous of your cheap and easy experience, by comparison.
And that's the thing with MK5s. Yes they break, but when they do, most of it is fairly inexpensive and easy-ish to get at. Anyone with an S4, S6, RS5 etc. Engine out job to do literally ANYTHING on it.
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And that's the thing with MK5s. Yes they break, but when they do, most of it is fairly inexpensive and easy-ish to get at. Anyone with an S4, S6, RS5 etc. Engine out job to do literally ANYTHING on it.
Yep
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Definitely seems that way, if I had small thin hands I suspect it would have been easier but it wasn't that difficult of a job.
Next few tasks are all cosmetic