MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: Rigsby on November 26, 2017, 06:43:43 pm

Title: Alternator/ thermostat help
Post by: Rigsby on November 26, 2017, 06:43:43 pm
Basically my thermostat packed up yesterday, temp on the gauge dropped to 0 but when stationary would start to rise back up and the heater wasn’t kicking out hot air. Does this sound like a thermostat problem?

I started looking at the car contemplating whether to do the job myself or take it to a garage. On inspection I noticed one of the alternator bolts was sticking out and nearly touching the aux belt. I noticed earlier this year that the prev owner has snapped the head off the bolt but now the bolt has worked itself loose.
So I went about fixing it now, tensioner off, aux belt off and managed to extract the bolt, I had an identical bolt lying around do put that in and as I was nipping it up the alternator tabs cracked.

Question is can I get the tabs welded back on or best to get a used alternator ?

Any advice welcome
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 26, 2017, 07:11:04 pm
New alternator is the way forward as there tricky to get out of that location and need levering out.
Title: Re: Alternator/ thermostat help
Post by: dronners on November 26, 2017, 07:17:26 pm
its probably going to be cast metal too which dosent weld very well...   at least it gives you an excuse to change the thermostat now..  silver linings and all
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 26, 2017, 07:22:52 pm
Ok, I didn’t know if cast aluminium could be welded.

I suppose I’m halfway there to replace the thermostat.
If I remove the alternator can the car be started and moved? Drive a short distance?
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 26, 2017, 07:37:44 pm
Yes you can start and move the car.

The job of replacing the thermostat is a twat of a job on these cars and you need M5 tripple square socket make sure you've got one, have you got a how to for the job?

If not this is worth a read.

http://www.pelicanparts.com/techarticles/Volkswagen_Golf_GTI_Mk_V/31-WATER-Replacing_Your_Thermostat/31-WATER-Replacing_Your_Thermostat.htm
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 26, 2017, 07:46:21 pm
Yeah I have been reading through the pelican parts how to.
Triple square is the same for the hpfp banjo bolt? If so I’ve got one
Everyone says it’s horrible job which is putting me off.
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 26, 2017, 07:49:09 pm
If you've got access to a spare car and aren't pushed for time so you can do the job at your speed then it's just nuts and bolts crack on and enjoy it.
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 26, 2017, 07:57:39 pm
Yeah I only work up the road so can walk.
I’ll get the parts ordered and crack on
Cheers  :happy2:
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 26, 2017, 08:01:17 pm
Keep in mind when your so far into the job to check the inline thermostats - this will help and enlighten you on that section.

http://www.mk5golfgti.co.uk/forum/index.php/topic,78341.0.html
Title: Re: Alternator/ thermostat help
Post by: fab5freddy on November 26, 2017, 08:19:26 pm
Shameless plug, i’ve got a brand new one for sale @Rigsby (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=11668) if your interested

http://www.mk5golfgti.co.uk/forum/index.php/topic,113172.0.html (http://www.mk5golfgti.co.uk/forum/index.php/topic,113172.0.html)
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 26, 2017, 09:30:38 pm
@fab5freddy (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=3064) too much for me atm, thanks for the offer though
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 27, 2017, 08:01:08 pm
Last bolt and the thermostat is out, this triple square one is kicking my ass.
I have an m5 spline bit, is this the same? It don’t fit
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 27, 2017, 08:06:26 pm
There's also a couple of torx 30 if I remember correctly especially one hidden behind the electrics!
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 27, 2017, 08:14:37 pm
Last bolt and the thermostat is out, this triple square one is kicking my ass.
I have an m5 spline bit, is this the same? It don’t fit
The tripple square is twelve points as this shows

https://www.machinemart.co.uk/p/laser-5218-m17-12-drive-spline-bit-socket/?da=1&TC=GS-040226218&gclid=Cj0KCQiAjO_QBRC4ARIsAD2FsXPbD3i-WnLPGH8vxZYKWLpcloobxSSG8nWF6WY68IGye0wA5JeRgEcaAi0qEALw_wcB

Not like a Torx six point as this

https://www.ebay.co.uk/p/Pack-of-10-Torx-Drive-T20-Screwdriver-Bits-Torx-T-20/542875513?iid=121391368215
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 27, 2017, 08:54:18 pm
Yeah that’s what I’ve got mate, m5 spline bit and it’s too big, nothing fits this basstard bolt .
Might have to get the dremel out

Are triple square the same as a spline bit? I thought they were the same?
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 28, 2017, 08:19:07 pm
For anyone wondering, spline are different to triple square.
Managed to get some proper XZN vag triple square  bits and fit perfect , thermostat is now out !!!
Title: Re: Alternator/ thermostat help
Post by: v4rley on November 28, 2017, 08:30:52 pm
Really ? I think they are the same..... :confused:
Title: Re: Alternator/ thermostat help
Post by: doylebros on November 28, 2017, 08:40:08 pm
For anyone wondering, spline are different to triple square.
Managed to get some proper XZN vag triple square  bits and fit perfect , thermostat is now out !!!

Well done. :congrats:
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 28, 2017, 09:02:41 pm
Not a lot of difference but they do differ, angle of the points
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fthumb.ibb.co%2Fh69Jcm%2FE228_F18_B_2706_474_E_A0_D3_36497_B308_F97.png&hash=d7436193cfadb459cb5add3a64a86f98c24bfae1) (http://ibb.co/h69Jcm)

Thanks for your help @doylebros (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=6153)
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 30, 2017, 07:28:17 am
Put her back together and it’s running rough nearly stalling?
Plus the coolant isn’t going down, I’ve only put 2 litres in and 5 came out??
Any ideas ??
Title: Re: Alternator/ thermostat help
Post by: Octoparrot on November 30, 2017, 03:04:13 pm
Sounds like an airlock, don't think that'd cause the rough running though, maybe check that everything is plugged back up properly?
Title: Re: Alternator/ thermostat help
Post by: pudding on November 30, 2017, 03:38:42 pm
Interesting on the triple square vs spline.  I've used splines on this job and others around the engine and not had any problems!  Bloody Germans.....premium fastener for premium engines  :grin:   They even use them on small low stress brackets where a regular 5mm allen would suffice!

Anyway...... you need to wait for the thermostat to open before it will guzzle the coolant down.  Can take ages this time of year.   Don't generally get air locks in Golfs as the expansion tank is above the engine, so air can escape.  It's usually on Jap engines with stupid radiator caps and things that air lock easily.



Title: Re: Alternator/ thermostat help
Post by: doylebros on November 30, 2017, 04:31:54 pm
Best recheck your work on the electrical connections disturbed during the job.

Additionally, suprised you got 5lts of coolant out - what hose did you remove for the drain down?
Title: Re: Alternator/ thermostat help
Post by: Rigsby on November 30, 2017, 05:30:23 pm
Cheers folks.

Update: disconnected the maf and removed the engine cover to have a look, started it and it runs bang on, connect the maf/airbox and it struggles and cuts out?

Title: Re: Alternator/ thermostat help
Post by: pudding on December 01, 2017, 11:46:52 am
Have you got VCDS?  It would be handy to see what the MAF reading is, and/or if there are any fault codes.

If you haven't got it, and assuming there are no hardware/wiring problems, try disconnecting the battery and try again with the engine cover on.
Title: Re: Alternator/ thermostat help
Post by: Rigsby on December 01, 2017, 07:56:57 pm
Have you got VCDS?  It would be handy to see what the MAF reading is, and/or if there are any fault codes.

If you haven't got it, and assuming there are no hardware/wiring problems, try disconnecting the battery and try again with the engine cover on.

No I haven’t got Vcds , I will try and disconnect the battery and try again.
Cars been in my garage all week now.
Seems very strange for the maf to be causing problems
Title: Re: Alternator/ thermostat help
Post by: Rigsby on December 02, 2017, 01:45:43 pm
Well the hasn’t worked, I’m at a loss now??
I suppose I’ll have to admit defeat and take it to a garage ... I hate being defeated

If anyone has any ideas please let me know, thanks

Would a vac leak cause this issue? But I’ve only removed throttle pipe and lower intercooler pipe, and theses look fine
Title: Re: Alternator/ thermostat help
Post by: Rigsby on December 03, 2017, 03:35:01 pm
FIXED- Drove it without maf connected for 5 mins until all the lights on the dash went out (from battery being disconnected) .
Turned it off, cleared fault code from the Maf being disconnected, connected maf back and runs great...........how bizarre