Audia8ld3

And it smokes a lot from exhaust plus coolant level is very low

mishar

Replacing head gasket based on that can be waste of time and money.

To be sure it is head gasket:

White smoke from the exhaust when engine is warm. Bluish smoke would be oil smoke and it would require different approach.

Bubbles in the coolant reservoir. Luck of heating.

Milky color of oil from coolant in it.

If all or some of those symptoms are present you still need to find which head gasket is faulty. You also have to resurface the head in order to prevent it happen again soon. It is serious undertaking. It may be cheaper to replace engine.

MP4.2+6.0

+1. Needs way, way, way more diagnostics than this. Add to Misha's list if you think it is going out the exhaust, first you pull the plugs and see if one of them is effectively steam cleaned. If not, also probably not head gasket.

Failure rate of head gaskets is really low. Almost none posted in history of this board. It's winter in northern hemisphere anyway (more normal condensation/water vapor in general), and we don't even know if it is oil smoke, fuel smoke or water vapor. Nor do we even know if it is leaking coolant elsewhere, including the not uncommon oil cooler pipe, maybe coolant bottle, water pump seal/blowout or 10 other places.

jandreas

For MY2006 Audi (BGK) optimized the cooling channels in cylinder #1 but the (new-to-the-A8) metallic head gasket design seems to have issues with the (now) thin areas around these channels.

ltooz_a6_a8_q7

No low coolant, no leaks, no oil consumption... I think when the engine is overheated one time, that's when all heck break loose.

Smoke coming out of the engine, low coolant, logically, there's leak on the coolant pipe somewhere, dripping to the hot muffler.


Cheers,

Louis