Temp Gauge Dropping

[CarlW]

So i've just recently noticed the problem, since i've noticed it, the car has been in the garage today having a new main thermostat fitted at the cost of £100 thinking that was the right thing that needed doing as the garage said the same, came out.. all is fine and dandy until... I've been for a longer drive tonight to test its working and basically.. It wasn't. The temp gauge doing exactly the same as before.. As soon as i put the heaters on, it drops from 90 to around 70ish then when i knock the heaters off, it goes back up to 90ish.. So, I'm feeling hacked off the fact i've blown £100 for what seems to be.. Nothing.

I've had a search and feedback I'm getting, is it could be a coolant temp sensor?

Is there anything else i could as the garage to have a look at again tomorrow? Or.. Will it definitely be the coolant temp sensor this time?

Also is it worth me trying to get some sort of money back from the £100 i seem to have wasted on something that hasn't actually fixed the problem?

Appreciate anyone's advice and help

[Alex157_gti]

Mind does this even on runs down motorway!

And nocited it today with heaters on!!

Never really tho much of it really!

[lukemk5gti]

So i've just recently noticed the problem, since i've noticed it, the car has been in the garage today having a new main thermostat fitted at the cost of £100 thinking that was the right thing that needed doing as the garage said the same, came out.. all is fine and dandy until... I've been for a longer drive tonight to test its working and basically.. It wasn't. The temp gauge doing exactly the same as before.. As soon as i put the heaters on, it drops from 90 to around 70ish then when i knock the heaters off, it goes back up to 90ish.. So, I'm feeling hacked off the fact i've blown £100 for what seems to be.. Nothing.

I've had a search and feedback I'm getting, is it could be a coolant temp sensor?

Is there anything else i could as the garage to have a look at again tomorrow? Or.. Will it definitely be the coolant temp sensor this time?

Also is it worth me trying to get some sort of money back from the £100 i seem to have wasted on something that hasn't actually fixed the problem?

Appreciate anyone's advice and help

I had the exact same work done, main thermo replaced 2 weeks ago and on the motorway it took me 30 mins to get to 90 and then when I turned the heaters on I dropped to 80ish deg.

I think it could be the inline thermo maybe so will possibly book it in next week for a look!

[DDM]

i think your diagnosis was correct with thinking thermostat, that's what i would of said, i wasn't aware the golf had 2 tho, but i definatley wouldn't say it's the temp sensor, the temp sensor control's the fuelling, the temp sender is the one that works your instrument gauge inside. i would say theres a possability of air still being in the system. also did you use a genuine part? a non genuine thermostat could open and close at different temperatures.

[GrayMK5GTI]

I had the temp drop: http://www.mk5golfgti.co.uk/forum/index.php/topic,80793.0.html

Which i fixed with a new thermostat - £100 sounds very cheap for a thermostat to be fitted? Cost me double that (and some  )

Temp sensor is a cheap fix - and quite accessible so maybe worth trying that?

Have you pulled the digital coolant  temp display up in the climate display? thats how i dignosed what mine was doing.

[GrayMK5GTI]

Before anyone asks (I know someone will  ) this is how to access the climate display "secret menu":

See here: http://www.golfmkv.com/forums/showthread.php?t=27

http://www.golfmkv.com/forums/showthread.php?t=9433

Note, 15:0 isn't oil temp. Can't remember what it is though.

[xjay1337]

I had the temp drop: http://www.mk5golfgti.co.uk/forum/index.php/topic,80793.0.html

Which i fixed with a new thermostat - £100 sounds very cheap for a thermostat to be fitted? Cost me double that (and some  )

Temp sensor is a cheap fix - and quite accessible so maybe worth trying that?

Have you pulled the digital coolant  temp display up in the climate display? thats how i dignosed what mine was doing.

Yeah... I would imagine it would be a non-genuine thermostat at that price fitted!
Genuine all the way.

[MC71]

^^^^ Just booked mine in with @vRSAlex for a new stat .......wonder if he'll price match the £100... Cough 

[SiofChester]

Not a chance they did the main stat for 100 including parts. It's 30 quid for the part and 4 hours work, so 20 quid an hour labour? Not sure that's a sustainable business model

[CarlW]

The part is on the receipt at £28 then £12 for coolant and £60 labour. It's a mate of mine that's just started up his own garage maybe 6 months ago.

[CarlW]

I had the temp drop: http://www.mk5golfgti.co.uk/forum/index.php/topic,80793.0.html

Which i fixed with a new thermostat - £100 sounds very cheap for a thermostat to be fitted? Cost me double that (and some  )

Temp sensor is a cheap fix - and quite accessible so maybe worth trying that?

Have you pulled the digital coolant  temp display up in the climate display? thats how i dignosed what mine was doing.

I haven't as of yet as I'm not clued up on it so I'll have a read of the thread in your next post and see if I can make anything out of that, like I say, the temp gauge is only fluctuating when the heaters are on, not when idling or doing between 30-70MPH.. Just want it sorting rather than waiting for something to go *Bang*

[CarlW]

Right I've clues myself up on that little trick with the climate panel but I'm unsire what number the left screen and the right screen should be on for me to know which is the temp gauge, of I was on the correct numbers, it was running constantly at 82.0 whilst the temp gauge on cluster was at 90?.. But I'm not sure if I had the climate panel right..

Sorry if this post sounds like I'm talking gobbledygook.. Haha.. Hopefully you can understand what I've just said

[dansmith180]

When my dash gauge is at 90 my climate readout is about 78 I think, same with vagcom plugged in the dash says 90 but the vagcom says 78ish. Not sure if there's another sensor for that readout maybe...

[SiofChester]

19.2 on the climate control gives you the actual reading that the ECU is using for fuelling. The dash gauge is damped, the coolant can be anywhere between 70 and 95 and the gauge will read 90

[CarlW]

Okay I see, will have a look in the next half hour or so and see what it's putting out, only thing is.. Is this going to give me any clues as to why my temp gauge is dropping when the heaters go on as I'm sure this isn't meant to happen as I've never seen it with the three MK5's I've had over the years..

Cheers,
Carl.