Hi there,
I have this weird problem with my car, an Audi A6 allroad from 2015 with the 3.0 tdi 218 CRTE engine. I bought the car in Nov 2018 from Germany and for 2 years I had absolutely no issue.
First issue (oil cooler leak)
The first problem that appeared was a leak in the gasket of the top oil cooler of the engine. The issue looked like missing coolant and was solved temporarily with more water and then in the service by replacing the the gasket and cleaning the oil cooler. Back then the error codes were shown in the dashboard (high temperature warning) as well and once the oil cooler gasket was replaced the error disappeared.
2'n issue (engine complete stall)
After 8 km (after I took it from the service) I was in town, stopped to a red light and the motor stalled. When it did this I was in Sport Mode and when I accelerated to start the vehicle the engine rev went very high even though I did not push the pedal to the ground and simply stopped. I could not restart the car from that point. I called a trailing service and got it to the auto service.
The first issue they discovered was that the Denso starter was bust as both wires were shut probably due to the fact that the motor was stalled and the starter could not move it. You can see the damage below (attached).
We changed this part with a new one and the guys tried to move the motor manually to see if there was any issue with the motor itself. Given the fact that the movement was not quite ok they decided to open the motor to see if there was any damage inside. When they did this they found metal bits in the oil pan that is under the motor as you can see below (attached).
These small metallic parts came from the bearings (I hope it is the correct term for the parts that look like a circle split in 2) of the crankshaft and they basically got stuck on the crankshaft and even shifted in their place and started to turn with the crankshaft itself.
Here are those parts after they were taken out (attached).
2'n issue repairs
At this point the following measures were taken:
1. The crankshaft was measured to make sure it is straight, the bearing surface was rectified and new bearings were installed according to the new specs in specialized shop.
2. A new oil cooler, oil pump, gaskets and a complete oil change was done
The motor has been reassembled and since the front part with the vehicle was disassembled, the tempomat needed a recalibration. This can only be done in Audi service so my service took the car there for recalibration. I asked them for a motor diagnosis to see if there was any error code or something that they ca see and my service cannot see with their computer. The diagnosis did not show anything at all.
When all this was done I took the car for driving and did around 300 km in various regimes: city, highway in both normal and sport mode. The engine seemed to have a nice sound, performed really well without any issue.
Since the cold season came when temps went below 0 the engine had a little lateral shake at cold start which was barely noticeable. This would disappear after 2-3 minutes and would never appear back up until the next cold start. I had previously a 2.0 TFSI A3 which had the same behavior for as long as I had the car (11 years) and nothing happened.
2'rd issue (engine starts shaking vigorously)
Yesterday I went again to a longer trip, started the car and after 30 km it started to shake more vigorously up to the point where you can really feel it. I stopped the car on the side and shifted to N. The shake continued and some weird noise was also hearing like someone would knock with his finger in a plastic piece.
I took the car back to the service on a trailer and we discussed the symptoms above and 2 issues were checked: whether there is any error code in the computer and there is none and the oil filter which again had some small pieces of metal in it, so I presume the same issue happened.
The problem is they did not say what was the cause when it first happened either and they just presumed there is an issue with either an oil pressure sensor or the oil pump. I suppose that any malfunction of either these would have triggered a computer error. They changed the first time both the pump and the pressure sensor, yet the problem remains since we do not have any clue what is causing this.
I mentioned I have the car for a little over 2 years, I bought it from Germany when it had 1450k and now it has 170k. The no of km is fine since it has all the service checks and changes done in an Audi service in Hamburg and it had only 1 owner prior to myself. Also the service of the car in these 2 years was done according to the manual at every 15k km.
I searched the forums for similar problems and I could not find anything. I hope someone could guide us or at least give a hint on what to check. I can provide pretty much any kind of data available with the tester or any other info as I have access to the service and I know them really well.
At this point the service recommends a new engine (from a donor car) that would basically be bought by me and installed by them. They also said they can buy a new crankshaft and bushings and install it but the guy with whom I spoke said it will do the same after a few hundred of km. Also I am little bit reluctant that they will make the repairs with all due diligence.
My questions now are:
1. What might be the cause of the first stall given the work done at the oil cooler? Some other people with whom I discussed said it might be related to the turbine eating oil. The turbo was not checked since nobody came with this idea on their end.
2. What might have caused the 2'nd stall since everything was changed and repaired?
3. The guy said he also talked to some Audi service consultant and reportedly this guy said these engines (3.0 CRTE 218) have some construction issues that generate these problems. I find it hard to believe an engine with this issue would make it to 170k km and only break when someone starts changing a gasket. Also I would have found complains about similar issues on the internet with people failing these engines from 2015 on, yet I could not find anyone with a story like mine. Is this an engine with common such faults?