A3 2.0L TDI Maintenance Thread

[futtret]

2015 S-line 31500 miles:

Went to start car, pressed clutch, clutch landed on the floor.
Little bit of research on youtube seems to suggest the master cylinder plastic shaft (aka laughing arm) likely broken after similar mileage, although the you tube vids are for an 8P engine rather than 8V engine, I think??
VW Scirocco Clutch Pedal Stuck To Floor - Master or Slave Cylinder Diagnosis How To DIY Golf A3 Leon - YouTube and Audi A3 no clutch... Fault finding and repair. READ DESCRIPTION! - YouTube

Struggling to get my silver heatshield fabric out of the way when looking under bonnet, but from what I can see so far, my A3 S-line looks a bit different to those videos - is that cos its an 8V engine and videos maybe 8P engines?

Any other thoughts as to likely faults , i.e master or slave cylinders?

[Crasher]

For pre 26-05-14 production, the master cylinder is troublesome, the part has been revised but there are a few mountings parts required which are genuine only

[futtret]

Slave cylinder cracked.
£950 repair bill, not dealership, 7hrs labour.
Enough to put me off VAG now tbh - pretty disappointing at 30k miles.

New clutch kit £265
Gearbox oil £35
New 'bearing' £45 (necessary?)

Flywheel OK acc to garage.
Should i expect further problems with clutch imminent?

[Crasher]

The slave cylinder is the bearing, typically you would get an LUK four piece kit (inc DMF) for circa £1k, not fitting a new DMF is something we would simply refuse to do.

[futtret]

The heater matrix used in the MQB platform (A3 8V, Golf 7 etc) is a joke, thankfully it is not a dash out job to replace.

Well, here we are...
2015 A3 2.0 tdi, 8VA, CUNA engine, 184bhp, 43000miles

My internal heating has generally stopped working (hot air not working, cold air fine), it gives out a slight luke warmth if blower on lowest level. Doesn't appear to using much if any coolant. Engine temperature sitting at 90degrees as normal.

Crasher, when you said the matrix was a joke, is it the matrix design that can't cope with the silica clogging it up, or is the problem being the silica sachet in my coolant reservoir, or is it residual sand in the system from manufacture.....
Maybe you meant that the location of the matrix was a joke?

Anyway, what to do?
New matrix & flush the cooling system prior to reinstating?
Also due a timing belt change, not been done from new. Get that done same time?

I'm a bit confused by all the internet chat about the silica bag bursting & clogging up matrix, but on many occasions the matrix seems to be clogged even though the silica bag is in tact. So is it just too much concentration of silica dissolving into the coolant that is the issue? Then clogging the matrix. Or is it sand in the system.

This training vid suggests the silica sachet is a failsafe against folk just topping up with water rather than with proper coolant (towards end of video).
Audi Engine1.6 / 2.0 TDI EU5 Service Training Information - YouTube

[Crasher]

I love the CUNA engine, change one letter to know how I really feel! The Silica bag is part of the problem in that it losses its effectiveness in boosting the silicate of the coolant which falls out of suspension and blocks the matrix, the bag does not split, internet myth. We reverse blast the system clean with the pressure was and then blow the water out with compressed air, then change the matix and refill with G12Evo; we use G12Evo concentrate and mix is 40/60 with distilled water, NOT tap water. The CUNA is evil for air locks, we use a vacuum filling bleed system and run the engine with the ODIS bleed procedure which is not on VCDS although there is a half hearted version where you can run the electric pumps individually but the ODIS procedure runs them together, revs the engine up and down and open the water pump delivery ring and with the vacuum bleeder on but it still sometimes takes two goes.

[futtret]

I love the CUNA engine, change one letter to know how I really feel! The Silica bag is part of the problem in that it losses its effectiveness in boosting the silicate of the coolant which falls out of suspension and blocks the matrix, the bag does not split, internet myth. We reverse blast the system clean with the pressure was and then blow the water out with compressed air, then change the matix and refill with G12Evo; we use G12Evo concentrate and mix is 40/60 with distilled water, NOT tap water. The CUNA is evil for air locks, we use a vacuum filling bleed system and run the engine with the ODIS bleed procedure which is not on VCDS although there is a half hearted version where you can run the electric pumps individually but the ODIS procedure runs them together, revs the engine up and down and open the water pump delivery ring and with the vacuum bleeder on but it still sometimes takes two goes.

Thanks for the info.
Do you usually replace the matrix with the same model (Valeo) or do you fit an improved version?
Presumably using the G12Evo coolant kind of removes the source problem being the crappy G13 coolant?

[futtret]

added a couple more queries:

Thanks for the info.
Do you usually replace the matrix with the same model (Valeo) or do you fit an improved version?
Presumably using the G12Evo coolant kind of removes the source problem being the crappy G13 coolant?
Upthread you mentioned 'not a dash out job' to replace the matrix....but am I right in saying the whole centre console + glovebox needs to be removed (there is a vid on you tube showing this...).
How many hours is fair to replace the matrix?

Regarding timing belt & water pump; would you recommend genuine VAG parts or Gates kit?
Not a scrimper, just like value for money...
Would you keep this car or time to get rid.....2015 A3 8V CUNA, 43000 miles

[Crasher]

There are two systems fitted, Valeo or Denso and we fit the relevant aftermarket units from Nissens which seem to be good value. Cam belts and water pumps we only fit genuine for the, in theory, 2 year warranty. So far so good with G12Evo. Yes the matrix is accessed under the dash, fiddly back aching job but at least not dash out.

[futtret]

So that's the heating matrix replaced, the timing belt & water pump, and G12 Evo coolant used. Oh and some other exhaust system sensor 2 or something, because seemingly there was another fault code on the diagnostics (even though the sensor on cylinder 3 glow plug was replaced a few weeks back).

Collected car, Engine Management System dash light (coily symbol) came on. Sigh. Went out in it later on, no EMS warning light, but when switched off the ignition gushing water sound coming from being the dash. The gushing water seems to occur when I switch the ignition on and off, ie without starting the engine. Noticed that coolant level was down at minimum level.

Air lock in new coolant?
Noticed Crasher warned of this upthread.
Would that be enough to bring the EMS dash light on?

How to rectify?