New Edition 30 owner - some issues

[dennis10]

Hi all,  My first post!  I've just purchased a Diamond black Edition 30 and have a few issues that I need to resolve - some that were apparent upon purchase, others that have reared their heads the moment money changed hands. 

1.  The coolant gauge fluctuates, under hard driving it gets up to 90, but gentle cruising etc and it drops down to around 70.  It's not erratic like I had on my 3.2 mk1 Audi TT which was the coolant sensor itself, it's a repeatable, consistent issue, so I'm thinking thermostat?

2. Most of the journey home after purchase was fine, but when I went to engage in some spirited driving, the clutch pedal wouldn't come back up a couple of times.  This was with a hot engine, but also did it yesterday from a cold start, again only a few times.  The clutch engages perfectly when it works as it should, bite point is good, gear change is good.  I've seen a fix about a shim in the end of the gearbox, but mine is a 57 plate Edition 30, so think it might already have this shim?  Any other ideas?

3.  Despite asking for a cold start, the previous owner took the car out for a blast beforehand, so I never experienced a true cold start on the car until I got it home - of course, I've now discovered a shakey rattle upon initial ignition, it clears after a second or two.   Here is a video of my cold start this morning:

https://www.veed.io/view/9b5021c2-de02-4c80-abab-a056ba26bdc8?panel=share

Do you think fuelling or maybe chain tensioner?  The engine sounds pretty spot on otherwise and drives well aside from these issues, although I have found that it has a very slight misfire at idle, particularly through the exhaust you can hear a blip when it does it.

Thanks for your help in advance

[ZoliWorks]

1) I'd get the thermostat replaced. Early models have 2-3 depending on whether they are automatic or manual, later models have 1-2. You have the main thermostat, behind the alternator, under the intake manifold. The inline thermostat, on early model cars, under the throttle body, above the electric water pump. And then a thermostat above your gearbox on automatic cars.

2) Could be a lot of things. Failing master cylinder, failing slave cylinder, failing clutch pressure plate, air in the system etc. The clutch bites good because it's self adjusting and compensates for wear. My clutch's pressure plate failed and got stuck completely. Had to replace everything clutch related as the pumps were on their way out too.

3) Looks the same way as mine used to. In my case, it was a combination of the stock fuel pump and a bad in-tank fuel pump (which I still have to replace). There's a valve in the in-tank pump to prevent fuel from draining out of the high pressure side, the HPFP and the fuel pipes, while the car is stationary. It's especially apparent after some spirited driving, where the pump heats up as well. In 30 minutes or so, I basically have no pressure in my fuel lines and I can hear it draining out. It got better after upgrading the HPFP cause it can move more fuel volume so it fires up faster, but my starts used to be worse than what you've showed.

Misfires: could be carbon buildup in the intake manifold and around the valves, bad plugs and coils. I'd get the manifold and valves cleaned and all the plugs and coils replaced.

[lazy]

I'm not an expert on Golfs but on most vehicles if the clutch pedal is sticking down it's usually a master cylinder, and if it's got a concentric slave, which it probably has as most modern vehicles do, it's a lot easier to change the master cylinder first.
Going off my recent experience with my car unless you're very confident and have lots of tools doing the main thermostat is a job for a garage, it's not an easy DIY job.
Hope that helps.

[dennis10]

Thanks for the replies guys - I shall check in those areas first.

I'm fairly experienced in doing jobs on my cars, most recently replaced an oil pressure switch and filter housing on my 2.3 vr5, which if you know the VR engine, is in a horribly inaccessible place - one of the worst jobs I've ever done.  So I'll probably take your advice and get a garage to take the pain!

I'm based in Buckinghamshire, I don't suppose you'd have any recommendations for trustworthy independents who know the mk5 gti platform?  I think I'm looking at thermostat, master cylinder replacement or at the very least bleed the clutch, and also possibly a walnut shell carbon clean - Is there anyone you'd recommend?

[lazy]

If you done those jobs to your VR5 I'd say you will definitely be capable of doing the thermostat and master cylinder yourself. I haven't done a master cylinder on a Golf but on every other one I've done they're quite awkward. There's a how to video for the thermostat on YouTube which makes it look easier than it is and you need an M6 multi spline socket which is something you might not have.
Unfortunately I don't know any garages near you.