GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Golf mk4 how to guides + info => Topic started by: T_J_G on 07 January 2009, 11:34
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This is for a 1.8T but I'm guessing this will be pretty much the same for other engines. Not the most comprehensive write up and lacking pictures but better than the guide I had;)
Symptons
My engine would reach 90 degrees but when I went onto a motorway or bypass the temperature would drop of to between 75 and 80 degrees even when the car is up to temperature.
Parts Required = £34.44
Thermostat £16 from VW 050 121 113C
Thermostat O ring £1.98 from VW
Coolant (3 litres in total of VW G12++) £16 from VW (£8 each) GO12A8GM1 . For this you can use stuff from Halfords (or another motor factors) but make sure on the back of the bottle it says it is suitable for your engine. Also you can catch the coolant in a tub and replace that but I replaced mine with fresh as I didn't know how long it had been in there.
Took about 2hr 30 mins to complete from start to finish but this was in snowy conditions so you can probably do it quicker if you're in a garage with warm hands!
NOTE: YOU DO NOT NEED TO REMOVE THE ALTERNATOR OR JACK THE VEHICLE UP!
The thermostat is located on the block just to the right (looking into the engine bay) of the alternator.
Remove the engine cover from the top of the engine and also the piece that goes round the inlet manifold. So you're left with this:
(http://img.photobucket.com/albums/v215/T_J_G/Photo0247.jpg)
Then remove this 'tray' that is in front of the inlet manifold by the two bolts that hold it onto the manifold, also unplug the 2 electrical connections that are connected and underneath there is a bracket holding an air pipe on undo this so you can move this part out of the way of the thermostat. The plastic pipe can also be removed from near the air box so you can get a good view of the thermostat housing. You can also just pull out the dipstick holder out to gain more room.
(http://img.photobucket.com/albums/v215/T_J_G/Photo0241.jpg)
Thermostat housing
(http://img.photobucket.com/albums/v215/T_J_G/Photo0242.jpg)
Now you want to remove the expansion tank cap, and reach to the bottom of the passenger side of the radiator and twist the tap and pull it out to drain the coolant. This should come out for the next few minutes so leave the tap undone.
Now you can remove the pipe that connects to the thermostat, note this will probably still be full of coolant!
Now you can see the two bolts that hold the thermostat housing on:
These can now be removed making sure that the thermostat and O ring come out. They are a bit fiddly to get them out so make sure you don't round the bolts and use a lot of patience.
Should be left with this
(http://img.photobucket.com/albums/v215/T_J_G/Photo0245.jpg)
You can also use this photo to locate the thermostat in the first place!
You can test the old thermostat in a bowl of hot water (straight from the kettle) mine opened by about 1 or 2mm so wasn't sure at the time whether it was faulty or not. It should also close when you take it out of the water. Although they do take a bit of time.
Right so it's time to refit everything, I greased up the O ring so that it 'stuck' to the thermostat and housing so it was easy to replace back into the whole. I also used some P1600 wet and dry paper to clean up the two surfaces that go together. The thermostat housing and the block. This will create less chance of leaking as it can fit together better.
Close up
(http://img.photobucket.com/albums/v215/T_J_G/Photo0246.jpg)
Obviously re fitting is what I've just said reversed but make sure you:
-Do the tap up on radiator before you replace coolant!
-re-connect the two plugs you disconnected
-re connect the air pipe and fit the dipstick holder back in place.
-re-connect the hose you removed on the thermostat housing.
Now is time to put the coolant in, so make sure the tap is done up on the radiator and pour 3 litres of un-diluted coolant in (at this point it will proboably show full to the maximum. So turn the engine on (make sure all plugs you disconnected are connected and so on!) and give the car a few revs. The water level should drop so top it up again and place the blowers on hot and number 4 in the car aiming at the windscreen. Then hold the car at about 2RPM for a few minutes and rev after. Obviously if the level is dropping keep replacing. when there is warm air coming through shut the engine off and do up the expansion tank cap.
Now fill a few bottle up with water and take the car on a test run, it will probably ask you for more coolant at some point. So just fill with the water and carry on, let the car get up to temperature and see if the needle drops when on a fast road. If it doesn't drop job done! If it does I would look at replacing the temperature sender or even the water pump.
Any problems feel free to PM me or email me and i'll try my best to help you!
The writer of this guide and GolfGTI.co.uk accept no responsibility of damage to your car when using this guide. Use at your own risk.
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Thanks for moving it Rhyso - hope it helps some people out!
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Thanks for moving it Rhyso - hope it helps some people out!
no worries mate - looks a good guide :smiley:
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Part numbers added
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Very good guide bud :afro:
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Very good guide bud :afro:
Cheers seems like it has helped a few people already:O Probably first of it's kind on internet as I couldn't find any with pics when I was looking to do it.
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Awesome guide!
Finally managed to get mine changed over. Managed to break the dip stick guide pipe (the bright orange bit of plastic) in the process though.
To help anyone else out who does the same thing as me - they get old and brittle - you'll want the guide pipe, part number - 06A 103 663 B - £2.12 from GFS :smiley:
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My car's temp just sits on cold most of the time and occ goes to 90 where it stays but then it moves down again the just above cold.
Would this be the thermostat or maybe a wiring issue ? Looks a good guide so may well come in handy if thermo.
:wink:
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I had that problem Gozza and mine turned out to be the Temperature Sender (http://www.golfgtiforum.co.uk/index.php?topic=88088.0)
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Ah thanks matey, will have a look into. Hopefully will be nice and easy to fix.
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If is temp sender, its 5 min job and 20quid genuine part. Im useless under bonnet and i managed it which says alot.
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Thanks will have a look over the weekend and make sure not a loose connection or similar plus see what colour one I need and put it right. Hate not knowing the temp of my car, drove it for about 30 mins the other day and sat just off cold :angry:
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not knowing when its up to temp so u can give it some does get annoying :laugh:
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funnily enough thats one of the reasons :laugh:
I also noticed it took ages for the heaters to get warm.
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funnily enough thats one of the reasons :laugh:
I also noticed it took ages for the heaters to get warm.
Sounds like a dodgy thermostat, to be honest though both are probably worth replacing!
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I did think that too but this is easier to replace so may start with this. I had the water changed recently so thought it may of solved it just in case loose connection etc but seems to have made it worse :/
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anybody near south wales fancy doing this for me i had one of my mate when i changed mine looks like his has failed now aswel lol ??? im now fed up of 30quid worth of v-power lasting 55 miles
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I did think that too but this is easier to replace so may start with this. I had the water changed recently so thought it may of solved it just in case loose connection etc but seems to have made it worse :/
You used G12++ not water right?!
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Was done by the garage and they used all the proper anti-freeze etc ;)
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IF your a dipstick like some of us and you snap your dipstick guide they are £3.49 from VW and they stock them. Good guide even if i did spend 9 long hours trying to get the bottom bolt undone on the thermostat to then find out its the temp sensor, which have now gone up to £32 < :sick:
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9 hours :undecided:
Now your putting me off :D
Just spoke to VW near me and its £25 inc the VAT/Seal, Can get a copy for about £9 inc delivery but dont want it to fail and have to do it all over again.
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Well on the flip side I removed mine in 30 odd minutes a few days ago!
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I think if u got aload tools next to u it's fine would of had mine of straight away but I rounded the bolt off which is wat made it that much harder lol
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Anyone know the size of the VW thermostat, friend of mine is getting one for about £7 inc P&P and its 54mm in diameter ?
Thanks :wink:
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Anyone know the size of the VW thermostat, friend of mine is getting one for about £7 inc P&P and its 54mm in diameter ?
Thanks :wink:
I bought a non-genuine one the other day and it's brand new that I could probably post to you? No idea if its the right one.
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Ooooh like that sound of that, but you say your unsure if for the MK4 1.8T ? Could you measure it for me when you get a moment ?
Thanks dude
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Ooooh like that sound of that, but you say your unsure if for the MK4 1.8T ? Could you measure it for me when you get a moment ?
Thanks dude
I bought it just to compare with another, but it should be for 1.8T. Ill measure and take some pics.
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:cool: did mine and a friends last night in garage. got to admit aum engine is a lot harder to do than a agu. :cool:
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is this the same guide for a 1.9 gttdi, ahf engine?
i really want to have ago and do mine, but dont wanna mess it up.....
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Just done mine today that bottom bolt what a pain in the arse but im glad i didnt break anything and all seams ok temp gauge now works as before it didnt even move. didnt do to bad took 2 half hours but if i had better tools would have been quicker.
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just done it. took me 30-40mins. i used a long, ball nose 5mm allen key and they came straight off. thermostat change takes 10 mins, its just changing the coolant that takes time.
thanks for the guide, was handy! would never have found the damn thing otherwise :D
:)
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just done it. took me 30-40mins. i used a long, ball nose 5mm allen key and they came straight off. thermostat change takes 10 mins, its just changing the coolant that takes time.
thanks for the guide, was handy! would never have found the damn thing otherwise :D
:)
glad you said about using the 5mm ball nose allen key as had to take mine off again job done in 30 mins :cool:
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just done it. took me 30-40mins. i used a long, ball nose 5mm allen key and they came straight off. thermostat change takes 10 mins, its just changing the coolant that takes time.
thanks for the guide, was handy! would never have found the damn thing otherwise :D
:)
:afro:
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just done mine and found Allen key to round the bottom bolt! so if you take off the alternator cable to the right of it you can get a thin socket and bar onto the bolt and undo it!!
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PITA!
Just replaced the stat on mine, had to slacken off the alternator which is pain too. Still job done and the temp is a solid 90 degrees. I got proper man sized hand which I don't think helped. Didn't bother with an allen key just got my socket set on the bolts. If I had to do it again I guess it would take half the time.
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Just like everyones when driving the coolant temp would drop down to about 70-80. Replaced the temp sensor. no change. The fan still kicks in at around 87ish....From reading from everyone else that theirs all run dead on 90 think I'm left with no option then to do the thermostat. So i'll be doing it this saturday morning. Ordered the 3 litres of g12 and the part itself.
Did anyone else realise a change in general running and fuel econemy once they had changed it? :smiley:
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Did anyone else realise a change in general running and fuel econemy once they had changed it? :smiley:
Yup a massive increase from crap mpg to marginally crap. So in the real world no, but I didn't expect it to.
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Replaced it at work. Didn't to remove anything to take it out. Quite straightforward to do but thought it would be off the top pipe from the temp sensor lol :shocked: not bottom pipe.
Since doing it found it runs dead on 90 - with no drop, no miss-firing on idle and seems to run smoother. Probably also because I reoved the throttle body and cleaned that too. :smiley:
Fan didn't kick in though which is odd. It only really kicks in on on days when it's very hot and I've been waiting in traffic for a long time. Not like my 1.6 se. :shocked:
Don't know why this is tbh, as I do have two new fans and they were tested off a battery. The wiring is fine. Fuses are fine. Changed the coolant temp sensor as well...
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i used a socket and ratchet, but with a wobbly extension, made the job so easy, done in less than 15 mins!
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just done mine. Took me 1min and 12 seconds piece of piss. Absolute childs play, dont know what took you lot so long.
Not really, been on it since three AND STILL AINT DONE IT!!!! I put the seal on in the wrong order and its leaked out all my nice new coolant... AAArrrrgghhhhhhh!!!!
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D'oh! :grin:
Worth mentioning, with the thermostat off you can check the coolant pump vane is still attached with a rummage around inside the block. If it spins, its goosed.
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I replaced mine but as I start filling the coolant it starts leaking out through the thermostat housing. Is it the O Ring or is there ment to be a gasket?
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I replaced mine but as I start filling the coolant it starts leaking out through the thermostat housing. Is it the O Ring or is there ment to be a gasket?
Have you put the o-ring the wrong side of the thermostat? :undecided:
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I replaced mine but as I start filling the coolant it starts leaking out through the thermostat housing. Is it the O Ring or is there ment to be a gasket?
Have you put the o-ring the wrong side of the thermostat? :undecided:
Does it go in before the thermostat or on the outside of it? Bit confusing I know
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mine leaked when i put it in the wrong way. think i ended up putting the thermostat in, and then the ring. it's been fine for a while now :)
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i did mine yesterday and have had to fill the coolant 3 times since!!! theres no leak but when i drive it and then have a look theres steam coming from around that housing.. refilled last night checked this mornin and coolant was in the same place.. went for a drive came back and was nearly empty again :-/ so is it stat .. then o'ring.... or as ive done o'ring then stat :-/ so dont wanna take it out again :-(
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tried do mine and rounded one of the bolts so not very happy anyone got any ideas?
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just to clarify boys took mine out redone in 30 mins on a drive in the cold with a frigin lead lamp as it decided to start pi***** out my nice new coolant :-( took out it is definateley thermostat in pocket o-ring over the top with a bit of silicone grease then screw housing over!! as soon as i put it in you could tell derrr all fits better as before the housing didnt seem in right alll for a bloody o-ring haha on the plus side mmmmm heat!!!!!! and mpg is quite a lot better if u drive like a fag its running 42 mpg :-D not much better when u put ure foot down :-/
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Hi, my first post here...
Apologies for posting in an old thread, but was wondering if there was a diagnostics code associated with this thermostat problem?
My recently purchased 53 plate 1.8T is having very similar problems and I'm trying to work out if it's the thermostat or the cooling sensor that's at fault...
Cheers in advance!
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There won't be a code show up for it.
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A code does come up. 1206 or something. Says problem with cooling mapping system (thermostat or temp sensor)
Both temp sensor and thermostat changed and temp now sits on 90 degrees.
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can anyone confirm which way the stat and oring go in then? stat then oring or oring then stat
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done this today, made a nice difference to my mpg! although took me about 3 hours to complete!
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Some friendly advice - unless you are a very good mechanic DO NOT ATTEMPT TO CHANGE YOUR THERMOSTAT on your mk4 1.8T
Do not be duped into looking at these pics and your £6 thermostat and thinking you can do it without removing the alternator and a whole host of other bits that are in the way - you probably can't and you will regret attempting it.
I wish someone had told me that this is a fkin pig of a job
YOU WILL BREAK YOUR DIPSTICK TUBE
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YOU WILL ALMOST CERTAINLY FAIL TO UNDO YOUR THERMOSTAT HOUSING because the bolts are practically impossible to get a spanner/socket on.
Pay the £50 to a dealer and let them do it.
This is probably the best bit of advice you will get.... this and wear sunscreen.
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Some friendly advice - unless you are a very good mechanic DO NOT ATTEMPT TO CHANGE YOUR THERMOSTAT on your mk4 1.8T
Do not be duped into looking at these pics and your £6 thermostat and thinking you can do it without removing the alternator and a whole host of other bits that are in the way - you probably can't and you will regret attempting it.
I wish someone had told me that this is a fkin pig of a job
YOU WILL BREAK YOUR DIPSTICK TUBE
and
YOU WILL ALMOST CERTAINLY FAIL TO UNDO YOUR THERMOSTAT HOUSING because the bolts are practically impossible to get a spanner/socket on.
Pay the £50 to a dealer and let them do it.
This is probably the best bit of advice you will get.... this and wear sunscreen.
in all honesty it aint that hard and yeah you can do it without removing the alt. Patience and right tools is key i=on this one I think.
I would encourage anyone who wants to save £50 to do this if needed.
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^^ Rubish, took me a few hours, but i did it with out removing alt. i didnnt even have to remove the "tray" with the electrical components on, just loosened it...
dip stick i did snap, but that was as i was putting it all back togeather i sliped and snapped it :rolleyes:
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^^ Rubish, took me a few hours, but i did it with out removing alt. i didnnt even have to remove the "tray" with the electrical components on, just loosened it...
dip stick i did snap, but that was as i was putting it all back togeather i sliped and snapped it :rolleyes:
mine did but to be fair it was already brittle :whistle: so i replaced it anyway had mine all sorted within the hour
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I have it on good authority that the thermostat location was decided by a Citroën engineer on secondment to VW - c##t
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Do you need any special tools for this job?