Long warm up time

[Bens313]

Hi All,

When we bought my Mrs GTI it wouldnt get up to operating temp. We replaced the Main thermostat and the car does get up to proper operating tempreture and sits there reliably. The problem is that it takes quite a long time to get up to temp. Luckily i have my GTI to compare it too which gets up to temp in about half if not less time. Ive seen people mentioning about a second thermostat, could this one be stuck open or possibly dodgy sensor?

Its not much of an issue as it does eventaully get there and i wouldnt think anything of it unless i had mine to compare.

Any information apreciated.

[Jons1001]

Hi mate found this from a previous thread on here;

Main thermostat failure - The car never reaches 90deg unless sitting in traffic. It then drops again when you hit the motorway. This is a hard job and not an easy diy. Expect maybe £200

Inline thermostat failure - The car takes abot 20 miles or 20 mins to reach 90. Even in the depths of winter it should be around 5mins or 5miles. The inline thermostat is very easy to do but you need a special "pliers" to undo the circlip. Still a 30min job and it doesn't require a full coolant drain down. Just top it up after.

DSG Second Inline - This isn't on all DSG's. Only some years have it. I don't know enough about this anyway but I think it's the same thermostat as the inline.

So looks like you need to replace your inline stat. Not that expensive I think I got a genuine part from ebay for about £25/£30 when I did mine. Just looked and the part number was 4E0121113.

[Bens313]

Thats perfect, thank you very much mate. Ill get the inline one ordered.

[LC5F]

I was chasing warm up issues with mine when I first got it - I also read about the 2nd inline DSG thermostat - but my 2006 didn't have one...
Main thermostat was main issue, but still struggling to heat up due to fans are staying on longer/for no reason?
I replaced both temp sensors one on the head above gearbox & the other on main thermostat (I was delighted to go back in there again) and the fans behave.

[Clarkj93]

In the off chance that doesn't sort it I had this issue on a non VAG car which turned out to bea mixture of over filling the oil and also using a too thick of an oil for that car. But yeah from what I've heard and experienced myself I'd imagine it's thermostat related.

[Bens313]

Thanks Clark, luckily i know the grade and have maintained the level. Good to know for the future though.

LC5F its a march 2005 so ive read it should have one. Going to have a poke around when she's back from work. If that's not it ill look into the fans though. Now you say it i remember a friend of mine who has a GTI also had an issue with overactive fans when he got it.

Some helpful info on the forum that i should have found before for any future visitors:

DIY Inline stat change - https://www.mk5golfgti.co.uk/forum/index.php/topic,78341.0.html

Info on the part and which cars have them (Page 3 about half way down) - https://mk5golfgti.co.uk/forum/index.php/topic,75756.msg798616.html#msg798616

[mjmallia]

All GTI's have one near the alternator.

GTI's with DSG have two.....the second being located above the gearbox

[RBS]

Next to alternator



2nd next to DSG cooler and oilfilter housing

[pudding]

Thats perfect, thank you very much mate. Ill get the inline one ordered.

I would check your car is actually fitted with one before ordering.  I made that mistake and it's been in my parts box ever since 

[Bens313]

Ill check later. If it is I don't suppose your near Oxford and want a tenner?... 

[pudding]

Nowhere near 

I can post it to you for a tenner though, it's of no use to me     It's a genuine one as well, no cheap tat on my cars 

[Bens313]

I have checked and i can see the inline Thermostat down past the alternator on the front of the engine. Jon is this the one you did without draininig the coolant? Im keen to drain it on my terms if necessary.

Ive messaged you about yours pudding.

[Jons1001]

I had mine changed at the same time as the main thermostat so it was already drained. Does say in the post i quoted earlier though that you don't need to, can anyone on here confirm?

edit: Just found this where it shows draining first. https://www.mk5golfgti.co.uk/forum/index.php?topic=78341.0

[LC5F]

Thats perfect, thank you very much mate. Ill get the inline one ordered.

I would check your car is actually fitted with one before ordering.  I made that mistake and it's been in my parts box ever since 

Definitely check first.
Got that same T-shirt as Pudding  - buying 2x inline, not cheap - but my tame TPS guys took the spare one back.
The whole 1 or 2 inline thermostat thing for DSG cars is tricky.

[RBS]

There is a good step by step on www.pelicancarparts.com for the thermostat

Also other interresting “how to” stuff for mk5