Thermostat stuck open?

[stainesy]

I've notice my new GTI temp gauge takes a lot of driving before the temp gauge goes up.
And when driving only stays at 70.
It only goes up to normal running temp when parked with engine on.
I'm thinking thermostat stuck open or removed.

Just wanted a few more opinions before I investigate.

[Gavv8]

I'd say its the thermostat and as its cheap and easy to swap might as well change it for peace of mind.

[northeast_gti-t]

+1 for your thermostat mine was the same when i got it replaced the stat and coolant and now sits at 90 degrees 

[itavaltalainen]

yeah, text book fault for thermostat.

[DCmk3]

I'm more leaning towards the side of there being no thermostat, but it's the same outcome if it's jammed open, it must be replaced.

[northeast_gti-t]

best to fit a genuine oem part to

[madsb]

best to fit a genuine oem part to

Just wanna point out that I bought this: http://www.mister-auto.co.uk/en/thermostat-coolant/bolk-bol-199041_g316_a999BOL-199041.html

which seems to be a lot cheaper than "OEM" and it works absolutely fine.

HOWEVER: Always check that a thermostat is working by putting it in a pan full of water and then boil the water.

[Jasikasisback]

You may curse your power steering pump as they are hard to remove and then even harder to put back in.

I suggest that you loosen the bolts that hold the pump to the bracket but leave the long bolt in at the top (the pump uses it like a hinge attached to the bracket). The two bolts that can be removed are the one with the teeth closest to the outside of the car and the other one on the other side that sits almost opposite..)

You can swing the pump on that hinge and then can get to the bolt underneath the power steering metal pipe...and remove the bracket with the pump still attached after removing the other bolts..

I did not do this and took the long bolt out at the top and now have to put the damn thing all back together. I will probably need to file and sand the metal so I can get the hinge back together..

you can rest the pump and bracket on a piece of wood/brick and don't have to take the power steering fluid hose off..this will save a lot of time and fiddling.

Then you can get to the thermostat housing..

The thermostat is easy to take out..but take a look to see that the bolts are not corroded...I was lucky and the bolts were still healthy..other people have had them snap off and then the real fun starts..

The new thermostat can decide that it doesn't want to sit in upside down and is difficult to keep it up there...


I used a Circoli thermostat with a rubber ring all the way around it..I believe that this will take place of the o-ring and this will not fall out while you are trying to put the housing back on...if anyone has else has put this type of thermostat in please chime in if I am wrong about this..

I couldn't get the normal thermostat to stay in as it would fall out and the o ring would not stay in position..tried numerous times to keep it up there..

One of my bolts was imperial instead of metric...that was a pleasant surprise...(guess it has been changed before by someone else...)

Why they made these things like this is beyond my understanding.

Anyone who tells you any job on a car is easy has never owned a vw...where rust and surprises are the norm....

there is a good guide to changing the thermostat and here is the link...

http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/coolingmaint/index.htm

I ignored the first part about the tensioner, some people remove the alternator but I didn't have any trouble removing it...

If you are very lucky you will be able to gain easy access to all three of the bolts that hold the bracket on an your job will be very easy...

WD40 is your best friend for this job...

[madsb]

If you can't be bothered messing around under your car:

Loosen bolts (there's two) holding the alternator. Press alternator down (there's a spring) so you can take the alternator belt off the pulley.
Remove alternator (remove the loosened bolts)
Remove metal plate covering water pump (remember which screws went were)
Remove waterpump (drain coolant before obviously - easiest to do by removing lower rad hose, as there is just a clip and then you can take it off)
Remove tstat housing from waterpump. If it breaks, get a new one, otherwise (if it doesn't leak) you're good to go.
Replace tstat (pretty sure it can't be put in the wrong way, so don't worry)
The o ring might be sitting in the housing, if it doesnt drop as you remove the housing.

Refitting is a reversal of removal

[madsb]

ALSO: My tstat housing would never have come off if I had done it under the car - the bolts needed powertools to come off, probably wouldn't be room for that under the car.