Engine Coolant Issues G30?

[puna]

I've just started having the common coolant temperature issue where it would take ages to heat up and then only sit around 70 with normal driving, and then finally hitting 90 when in traffic or driving quickly.

The car is a manual, so I replaced the inline thermostat and the old one was in fact broken. However, on my drive home (around 5 miles), the car would get up to 60 relatively quickly compared to previously and then sit at 60 instead of 70... It won't hit 90 at all. I've also ran it with VCDS and the temperature on the guage is matching that through the VCDS logs, so I don't think it could be a faulty sensor?. The only other thing I did differently was put in some G30 coolant (The coolant said it was suitable for pretty much all VAG cars) instead of G12+, now could this be causing the drastic drop in temperature? Or could it possibly mean my main thermostat needs replacing as well? Although I don't quite understand how replacing the faulty thermostat has now made my coolant temperature issue even worse.

Any pointers would be appreciated.

[puna]

Ok, so I have bought some G13 and will flush out the G30 stuff (no idea why I didn't go OEM with this).

I will also replace the main thermostat, as I imagine the poor temperature issues will still persist. Now the question is, indy or DIY? I've looked at a couple of tutorials, none seem as clear as I would probably like. Is this job as difficult or as complicated as it seems?

[99hagued]

Sounds like faulty main stat and is quite a crappy job to do

[The Red Warrior]

Ok, so I have bought some G13 and will flush out the G30 stuff (no idea why I didn't go OEM with this).

I will also replace the main thermostat, as I imagine the poor temperature issues will still persist. Now the question is, indy or DIY? I've looked at a couple of tutorials, none seem as clear as I would probably like. Is this job as difficult or as complicated as it seems?

Did you get this sorted @puna ?
It sounds almost the same as me.
Manual GTI, replaced my coolant with a G12+ version as what was in the car when I got it was no longer that pink colour so I'm guessing it had different types mixed previously.
Since then the temperature on the dash shows about 80 rather than 90 like it always used to. I just assumed my new coolant was doing a better job of cooling than the old stuff.
I have VCDS too if I should do something with that. I'm new to VCDS but may as well make the most of it.
I'm prepared to change one or both thermostats if need be.
Ta

[pudding]

It will be the main thermostat.

I didn't read any guides, I just took stuff off until I was able to get at the thermostat.  I found the easiest way was to Jack car up, remove under tray, Remove alternator, belt tensioner & throttle boost pipe and then I could get at it from above and underneath as appropriate.

The part itself is cheap, which makes up for the faff of replacing it.

[The Red Warrior]

Cheers, I reckon that's the way I'll approach it as well.
Ordered the part last night.

[ducman77]

Just completed this job last week.

I had exactly the same symptoms as you. New thermostat will sort you right out 

The job is a pain in the balls. But very doable.

I have bruises all up and down my forearms from trying to do all the required work in the tiny space available 

As said above,,,

Undertray off...
Boost pipe off...
Drain coolant from where the lower radiator hose meets the electric water pump under the car...
Auxiliary belt off...
Tensioner out...(optional)
Prize the alternator out with a pry bar....
There are three pipes attached to the thermostat...
The two rubber ones on top and bottom are simple enough to remove...
The metal one coming out of the front of the stat requires you to remove the two small triple square bolts holding it to the front of the engine block so that you can then wiggle it enough to get it off....
Remove the main stat...
Replace with new stat....

TOP TIP for reassembly;
Push the metal "bushes" on the alternator out a bit before you try and refit it. Otherwise it's way too tight a fit and you'll never get it back in. Don't worry the bolts will pull the bushes back into their correct position as you tighten them up.

Now enjoy your car behaving like a normal car because it actually has a working thermostat. Hallelujah 

I found this video quite helpful.....

Hope all that helps.
Regards,
Dave