ModestW12

My dealer has the engine partially dropped to replace the G62 coolant temp sensor in the back of the engine and one of the torque mounts (all under warranty thankfully). While the engine is partially out is there anything else I should considering replacing out of pocket as preventative maintenance to avoid out of warranty labor costs for an engine drop in the future?

I tried an advanced search but I must not be using the right search terms as I keep getting lists of unrelated posts no matter what I try.

QuattroDaniel

Hello ModestW12-

My S8 had the engine out last year for similar issues and I asked the same question. Not sure if these apply to your W12?

Thanks to 'richard-tx' for the advice, which was:
If it were mine I would replace the O2 sensors, all of the hoses at the rear of the engine. Pop the covers and check the timing chain tensioners and replace the plastic chain guides. If you have that oil cooler pipe, replace that with aluminum.

Might as well replace the water pump with a genuine Audi pump and the serpentine belt too.

Check all vacuum hoses and replace as needed.

Got a solar sunroof? Might consider replacing the blower motor as long as it is so easy to replace now. Clean the evaporator coil and put in a new cabin filter. There are some very good coil cleaners out there. If garage kept and parked under cover then let it go.

ModestW12

Thanks for your input Daniel, I'll pass this along to my service adviser (now the service manager but he's worked with me since my first D3 and still helps me out personally). I forgot to mention in the original post they also inspected and proactively replaced several hoses in the back of the engine that are subjected to a lot of heat soak.

TSHong

+1 on the O2 sensors that are hard to get to would be my main concern.

MP4.2+6.0

I never had any issues with the W12 O2 sensors that are hard to reach, which are some of the post cat ones. The pre-cat ones are all reachable under the hood--honestly easier than the 4.2's. W12 sensor issues are also often actually the car side connectors, all clustered up by the passenger side air box. There is a TSB on it.

If you are doing the water temp sensor--for which engine dropping is not necessary if you just take off the intake manifold to (barely) reach it--then consider the cam sensors. I lost both exhaust cam sensors between about 105 and 120K miles. Perhaps those exhaust ones relative to the intake ones because the exhaust sensors are closer to that heat. The driver's side exhaust one is virtually right next to the water temp sensor, and of course the other head one opposite it. My passenger side one also had some heat damage to the wire insulation, which I was able to repair. Unfortunately, in a scenario like your repair situation, the dealer parts price is more than twice what they cost if you just buy the Bosch OES sensor from autohauosaz.

ModestW12

I showed the service adviser the old post by Giovanni about removing the intake manifold to get to the sensor but the warranty company had already approved the work and he recommended dropping it to replace the hoses back there.

Thanks for the input on O2 sensor accessibility/reliability and the cam sensor suggestion. I'll pass that along.