Audi A6 2.5 TDI: OT Markings Explained

Hello!

Apparently, the heat and sun today in Frankfurt have affected me somewhat, because I can't find any timing marks (OT markings) on either the camshaft sprockets or the crankshaft sprocket of this Audi A6 2.5 TDI.

Does anyone happen to have a (helpful) tip?

'Thank you.'

MKB is actually AKN.

Hello, you can't find it because it doesn't exist. The crankshaft is brought to the top dead center (TDC) position by a dowel, and the camshafts are aligned using two thin rulers.

Best regards,
Volker

Hi,

Okay, open the oil filler cap and take a look at the camshaft. It's not designed for adjustment, but it can give you a rough idea. To do it properly, you'll need the two rulers and the crankshaft dowel.

Hello!

Okay, it seems to be working now. It appears the issue was only with the crankshaft and the fuel injection pump being misaligned. I suspect the left camshaft might also be slightly out of alignment, but I need to get all the necessary tools tomorrow first.

Ugh, it's annoying that you can't check the right camshaft through the oil filler cap or something similar; the left one is clearly visible.

Hello, I really hope you didn't use the "OT" marking on the camshaft as a reference point. That would be very, very inaccurate.

Best regards,
Volker

No, I just wanted to check if the waves are roughly aligned with the timing marks, because a 'so-called expert' before me had messed up almost everything. But it seems to be okay, although I'm not 100% sure about the right side. Can we use the position of the wheels relative to the timing belt as a reference point?

Greetings.

Hello m3nx,

Unfortunately, the NW (crankshaft) pulleys cannot be used as a reference point because there are no manufacturing markings on them. Many workshops make their own markings on the pulleys before changing the timing belt, which often works well, but not always, and in your case, it's not applicable because, as you mentioned, everything is misaligned. So, definitely get the tools mentioned above. This will save you a lot of rework and give you the certainty that the crankshaft and camshafts are properly aligned.