My 2015 A8 TDI has 117k miles.

The car is losing oil and coolant into the valley for sure (boroscope shows it’s full of puddles), it also has begun to severely stutter (way more than normal) under light throttle the last 3 months. I worry about fuel pump issues as well as the usual oil cooler, egr, gaskets, plates, main seals, oil pan gaskets and plastic bits that are problematic as the engines age. I have 3000 miles left on the emissions warranty and I want to expose as much as I can to Audi in hopes they will cover some of it.

I took the car to Audi of Erie, PA last week and wanted to give them the benefit of the doubt that they would be diligent on my service request, you be the judge.

Here is what they left me in voicemail friday:
"We looked into your coolant leak and we think we have an idea on where it's coming from, we checked that there are no visual drips or leaks or wetness underneath so we added dye to the coolant. We think it may be actually going to the EGR system and coming out the exhaust but it's only seeping a little bit at a time so for now we suggest you drive the car and bring it back when the low coolant light comes on again, you owe us $145 for diagnostic fee at this time."

They ignored my oil leak and stuttering issue entirely.

What questions should I ask or how should I proceed? Is this Audi's SOP? Seems dismissive and minimalist. I expected pressure tests, valley leak checks etc.

 

I won't speak to the stuttering, but oil and coolant leaks in the valley are a known issue for our engines (CPNB) over time. Oil cooler gasket leaks are one of the known issues. I suggest doing some research (there are several good threads in various forums such as Club Touareg with a virtually identical CNRB engine) then approaching Audi of America directly. I had a slow coolant leak and oil leak, my dealer did tests (pressure, dye, etc.) and recommended a complete valley reseal and water pump and stated none would be covered by the extended emissions warranty. I contacted AoA directly and described my parts list from the dealer's estimate. AoA got in touch with the dealer and by the next day approved the work (including the water pump which was totally unexpected). There is a coolant bypass valve with a plastic housing that is directly under and one short hose away from the EGR valve that's known to be a coolant fail point. Per research I described that part when talking with AoA, don't have any idea whether it made any difference to the outcome. Good luck, hope you have some success with warranty as it seems to be mixed.

 

As prior reply mentions, the thermoplastic housing adjacent to the oil cooler (cylinder head coolant circuit control valve; feeds the oil cooler and EGR Cooler, as well as the cylinder heads) on the Gen 2 TDI engines is generally the coolant leak culprit, but most dealerships tend to just blame the oil cooler's seals for the leak even though they'll tell you they don't know exactly what's leaking. Whatever is leaking, those oil cooler seals have to be R&R'd during the coolant clean-up, so bit of a moot point.

If you have the Gen 2 TDI engine, there's plenty of history to know the plastic housing on the cylinder head coolant circuit's control valve cracks/leaks coolant consistently somewhere around 110k miles; your mileage may vary somewhat, or more likely you just won't notice it's leaking as it starts off as a fairly slow, regular loss of coolant. I have a Gen 2 where it leaked slow/consistently for close to a year while the Audi dealers said there was nothing leaking, then finally performed an oil cooler reseal R&R, but didn't identify/resolve the root-cause leak (this plastic cylinder cooling circuit control valve housing), the leak continued as before, then once it began overflowing the engine valley took it to diff Audi dealer who likewise denied it is a covered item via TDI warranty, escalated /opened case with 'big Audi', and then it finally got fixed. Unfortunately, you've really got to know what's going on before you take a vehicle to an Audi dealer, because they will try to flim-flam their way out of performing warranty work, even if that means lying to your face and/or misrepresenting what's actually going on with your car.

If you own one of these TDI's with Gen 1 or Gen 2 engines, know that both TDI engines can/will leak coolant into the engine valley, with the main difference being the actual source of the coolant leak. It's super easy to remove the cap on the coolant tank (when car is cold, preferably), and visually verify the level inside tank. There's a bright yellow, graduated measuring device inside of the tank to indicate where the coolant level should be maintained within.

 

Audi is replacing the oil cooler gasket under warranty. I only have 3k miles left on the warranty.

While in there what else should I have them do as preventative measures? I am thinking the plastic coolant control valve for starters!

What else?

 

Have you not been listening? All items mentioned prior are covered by the TDI warranty, but unless yours is obviously leaking into a technician's face, for example, they will generally misdiagnose it as the oil-cooler-plate reseal jobber, which gets them in the general area, but not to the actual root-cause issue. What you need to do is ask them to pressure test the secondary coolant circuit, which feeds to the cylinder head/EGR/Oil Cooler, etc. It has it's own coolant shut-off valve/bypass valve to isolate the entire circuit...once the circuit for cylinder head feed coolant valve is pressurized/opened, the leak source can then be visualized...simple diagnostics.

Here's a link to help you understand the known issues for Gen 2 TDI engine. There is a similar video for the Gen 1 TDI engine as well, and also an overview video for all the 4L Q7 series engines:

 

I am listening, that’s precisely why I posted. I did ask them to test the secondary circuit, they said there are no other leaks. I don’t have the luxury of much mileage left on the warranty so I am replacing items preventatively for the sake of being in there. Well worth the $100 for the valve in my mind.

Thank you for the help!