I was hoping the same thing - I left the reservoir cap in place but coolant still came out very quickly. I think the position of the sensor within the system means spillage is unfortunately inevitable.
Not sure, but isn't the cap a one way valve, allowing air in, as coolant cools, but not out, to maintain pressure. Cap off, and cling film on might work.
Update 5: VCDS Scan

Hi all,

Today I got VCDS working and performed a scan on my A2. I opted for the free unregistered version of VCDS Lite and a cheap (£4.95) USB - OBD2 KKL FTDI cable as a starting point to see if I could get a diagnostics tool without spending a lot of money. In the future I intend to upgrade to a more complete version of VCDS but couldn’t justify the investment right now.

I downloaded a driver for the KKL cable from this site, as recommended in this related thread, onto a Windows 10 laptop. Following this I connected the cable to the laptop, and checked it was being detected in the Windows Device Manager - it was appearing under Ports (COM & LPT) as USB-SERIAL CH340 (COM3).


Finally I connected the cable to the car’s OBD2 port, started the VCDS-Lite software, tested COM3 with a BAUD rate of 9600, and performed an auto-scan.


The scan found two faults - one engine related and one ABS related. The engine fault appears to be due to the bank 1 oxygen sensor - and from what I understand this is a common issue on the 1.4 petrol engines, although easily misdiagnosed. I’ve had the engine light come on intermittently after cold starting the car a few times in the last month and suspect this is the cause. I plan to remove the exhaust heat shield at the front of the engine, inspect the wiring to this sensor, and replace the unit with a genuine part if necessary.


The ABS fault is interesting as I haven’t had any issues or ABS warning lights - the fault does state an intermittent signal so this could be why? If anyone could provide further information on this I’d be very grateful.

Thanks for reading,


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Update 6: G39 Lambda Probe (O2 sensor) Replacement (DIY Guide)

Hi all,

Following my previous post I have decided to replace the bank 1 (pre-cat) lambda probe to address my engine light and fault code. I haven’t been able to find a full ‘how to’ guide for this job, so thought I’d document my own experience to potentially help others in the future. It’s a bit fiddly but fairly straightforward, and took me (a semi-competent DIYer) just under an hour.

This job was performed on a 2002 1.4 petrol (BBY) engine.

ItemAudi part codePart installed
G39 Lambda Probe036 906 265 JNTK NZA11-V1

Tools required:
  • 10 mm socket (+ wrench and extensions)
  • 22 mm open ended spanner
  • Dead Blow hammer *optional*
  • WD40 penetrant *optional*
DIY Guide:

1) Remove the marked 10 mm bolts - two holding the plastic cable guide, three holding the exhaust heat shield. The bottom heat shield bolt is tricky to get at and was the most corroded.


2) Disconnect the heat shield hose.
3) Remove the exhaust heat shield - it pulls up and out of the engine bay. This will expose the lambda probe.


4) Slide the lambda probe electrical connector from the metal guide and disconnect it (this is a standard A2 electrical connector clip, push the tab until it clicks then pull the two pieces apart).
5) Remove the lambda probe with the 22 mm spanner. This is the hardest part of the job as the probe will most likely be seized in place. I found a combination of WD40 penetrating fluid, running the engine for a few minutes to get the manifold hot, and tapping the end of the spanner with a hammer eventually loosened the probe.


6) Install the new probe being careful not to twist the wires when screwing it in. Tighten to finger tight + ½ -~ ¾ turns with the spanner (35 ~ 45 nm) as per the probe instructions.


7) Reconnect the probe electrical connector and slide it back into the metal guide. This is a good point to double check the wiring for the probe isn’t twisted.
8) Reinstall the heat shield, hose, and 10 mm bolts.

Extra information:


I hope this helps anyone attempting this themselves.

Thanks for reading,
Would coolant loss be minimised, if the cap on the reservoir was sealed? Thinking no air in, no coolant out.
Works in my central heating system ...
(Just in case someone sees this thread later)

I thought that same, but if you aren't fast, all of it up until that section, so like >1litre.
As you remove the g62 sensor, the hole is just too big, to create enough vacuum to hold some fluid inside. The sealed cap barely helps anything, it's like opening a bottle of coke upside down. If you need to change the g62, get a bowl underneath and cover the electrical parts with plastic bags. The coolant will almost freely pour out.

WARNING: I'd wasted a lot of coolant and the engine even overheated as well during test drive, which I never saw before, because 1 small thing I'd missed!
When I tried quickly swapping the g62, I didn't realise the old sensor's rubber O-ring seal got stuck inside the tube! When I'd tried to attach the new sensor many times, it didn't exactly fit, so the coolant kept leaking. Took me many stressful tries in that narrow space, meanwhile trying to minimise coolant loss as well, which had failed of course, also not damaging the short cable, plus a short failed test drive, to realize the O-ring was stuck inside and due double stacking, the retainer clip just partially held the sensor!
After realizing this, was getting dark as well, I'd fixed it finally. I had to use the old O-ring though, as new one didn't fit exactly, but it was in good condition fortunately. Thankfully all was fine after that, but I had to get more coolant later and cleaning up the driveway too :/
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Update 7: Various Winter Fixes and Upgrades

Hi all,

Over the winter I’ve been steadily progressing with my A2.

Firstly, the heavily oxidised headlights (and cracked passenger side taillight) have been replaced with some in much better condition - when the weather improves I plan on restoring and protecting these to keep them from oxidising.

Late last year I managed to decontaminate, machine polish (1-stage), and protect the entire car, which made a huge difference to its appearance, removing all of the small scratches and dullness from the paint. Now the sunlight is coming back you can actually tell that the car is cobalt blue. I’m planning on giving the car a 2-stage polish later in the spring (when I restore and protect the headlights) to remove anything I missed and get the car shining.


Up next I replaced the badly worn plastic steering wheel with a mk1 TT leather wheel. I was originally planning on installing a leather a2 wheel but when I found the TT wheel for a good price I couldn’t resist. Elsewhere in the interior, I managed to repair the broken cup holder and ashtray; prior to this the cup holder was stuck out, and the ashtray was stuck closed - they now both work as they should.


I visited @timmus who resolved my driver door lock issues (after seeing what this took I’m very glad I didn’t attempt it myself) and retrofitted cruise control. I would highly recommend Tom’s services. As a result of the door lock issue resolution, the fuel flap switch now works which is another item ticked off the list.

Finally, I recently replaced the standard SE 6 spoke alloys with some Audi A1 16” (8X0601025G) alloys. This was always a long term plan as I really like the look of these alloys on the A2, however a combination of finding some substantial sidewall damage on my current front nearside tyre, and a good set of these alloys appearing for sale locally expedited the decision.


The A1 alloys have 215/45/ R16 tyres and were a straight swap with the SE 6 spokes which had 185/50 R16 tyres. There’s no rubbing issues, although the wider tyres definitely slightly change the feel of the car (a little more planted and a little less agile), and I’m sure there will be a small fuel efficiency penalty.

Thanks for reading,
Update 7: Annual service and gearbox oil change

Hi all,

No updates from me in a while as I've enjoyed 6 months of trouble free motoring - the other week I gave my A2 its annual service. Whilst doing so I also flushed 3.5 L of cheap (but still within spec) engine oil through the system to clean everything up. To perform the flush I drained the old oil, filled the engine with the cheap TRIPLE QX flush oil and let the car idle for 15 minutes, drained the flush oil and filled with new Castrol oil. Below are photos of the flush oil before (a) and after (b) the 15 minutes of idling.

ItemAudi part codePart installed
Engine oilVW 502.00 (spec)Castrol Edge 0W-40 4 L (only 3.5 L used)
Engine oil (flush)VW 502.00 (spec)TRIPLE QX Fully Syn Engine Oil 5W-40
Engine oil filter030 115 561 ANMann W712/52
Sump plugN 90813202Generic plug and washer
Air filter8Z0 129 620Bosch 1457433538
Pollen filter6Q0 820 367 BMahle LAK120


I also drained the old gearbox oil and replaced it with VW G 060 726 A2 spec oil. Following the steps outlined in this thread (picture posted by k7aus is the best reference), I used a funnel/teflon tube fed down through the engine bay (see photo below). Approximately 1.9 L of oil came out of the gearbox, and the same amount went back in. A comparison of the old (c) and fresh (d) oil are shown in the photos. The gear changes are now noticeably smoother and no cable adjustment was required in my case.


Thanks for reading,