A6 3.0 tdi stalls and no error code is present

[shuffless]

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?

[Stevey Y]

Hi to be honest it looks like a good old fashioned oil pump failure, the bearings look as though they have had a good heat up, I think at that point I would have scrapped the engine as with that amount of debris floating around the only real way of rebuilding it would have been to have it out strip it right down and have the block and cylinder head hot tanked and the oil ways steam blasted to get rid of every last piece of metal, any small pieces of metal hiding in the oil galleries will eventually come out causing catastrophic failure of the new bearings, if I was you I would source another engine because unless you have your one professionaly rebuilt its just going to keep on killing the new parts you put on it.

[shuffless]

Hi, I believe the oil pump would have triggered some sort of error code on the computer, yet I had absolutely no error before or after the event about oil pressure or anything related to this. 

Also, I discussed today with someone who said that a plausible theory would be that they messed up the installment of the oil cooler which triggered a mix of oil in the coolant while the engine ran and when it stopped the coolant entered the oil paths. During its working oil pressure should be around 6 bar and should have pushed some oil in the coolant. The problem is I do not know if this happened since I was not there when they emptied the oil from the car or the coolant. 

The question with this theory, which seems the most plausible for what happened there, is whether having water in the oil could create such damage to the crankshaft.

[Stevey Y]

18 hours ago, shuffless said:

Hi, I believe the oil pump would have triggered some sort of error code on the computer, yet I had absolutely no error before or after the event about oil pressure or anything related to this. 

Also, I discussed today with someone who said that a plausible theory would be that they messed up the installment of the oil cooler which triggered a mix of oil in the coolant while the engine ran and when it stopped the coolant entered the oil paths. During its working oil pressure should be around 6 bar and should have pushed some oil in the coolant. The problem is I do not know if this happened since I was not there when they emptied the oil from the car or the coolant. 

The question with this theory, which seems the most plausible for what happened there, is whether having water in the oil could create such damage to the crankshaft.

Hi, I have seen engines that look like the inside of a Hellmans jar but still run, if you consider that most oil pressure sensors only trigger at just under 2 bar by then you can safely assume its game over, judging by your pictures the big end bearings have had a lot of contact with the crank journals that is what has torn the chunks of white metal away, if you look at it logically the journal and bearings use what is almost an interference fit, this is to hold the oil between the the two this causes the oil to form a wedge which the two surfaces operate on in opposite directions, the holes in the crank journals and bearings allow the oil in and out and are designed to cope with the demands of higher than normal oil pressure.

If the surface of the crank journals are even slightly scored they will compromise the the integrity of the new bearings, in some cases you could remove very light scores with a light polish, worse case scenario crank out re ground and oversize bearings fitted. I think the most plausible explanation is that the oil pressure dropped, which they have not designed a monitor for, therefore that caused the original problem what did not help you was the fact that there was partial deposits of metal in the oil galleries which then would have been pushed round in record time by the new oil pump, if they are suggesting a new crank I would say that they have worked out that the old crank was not serviceable in the first place, then there is the other consideration what are the pistons and cylinders like on your engine.

Cam sad to say you only have three options, get your unit rebuilt by a reputable engineer, source a second hand engine, cut your losses sell the car as a rolling project  then go and buy another car.

Regards Steve 

[shuffless]

20 hours ago, Stevey Y said:

Hi, I have seen engines that look like the inside of a Hellmans jar but still run, if you consider that most oil pressure sensors only trigger at just under 2 bar by then you can safely assume its game over, judging by your pictures the big end bearings have had a lot of contact with the crank journals that is what has torn the chunks of white metal away, if you look at it logically the journal and bearings use what is almost an interference fit, this is to hold the oil between the the two this causes the oil to form a wedge which the two surfaces operate on in opposite directions, the holes in the crank journals and bearings allow the oil in and out and are designed to cope with the demands of higher than normal oil pressure.

If the surface of the crank journals are even slightly scored they will compromise the the integrity of the new bearings, in some cases you could remove very light scores with a light polish, worse case scenario crank out re ground and oversize bearings fitted. I think the most plausible explanation is that the oil pressure dropped, which they have not designed a monitor for, therefore that caused the original problem what did not help you was the fact that there was partial deposits of metal in the oil galleries which then would have been pushed round in record time by the new oil pump, if they are suggesting a new crank I would say that they have worked out that the old crank was not serviceable in the first place, then there is the other consideration what are the pistons and cylinders like on your engine.

Cam sad to say you only have three options, get your unit rebuilt by a reputable engineer, source a second hand engine, cut your losses sell the car as a rolling project  then go and buy another car.

Regards Steve 

Thank you Steve for taking time to reply. 

Originally if you look at the history of the works they did they have replaced the gasket of the oil cooler. My take is they messed something up there allowing oil to get out of the system into the water coolant since when it works it is around 6 bar while the water pressure is around 1.2 -1.5 bar at most. When the engine stopped the flow might have been the other way around since the water pressure persists due to working temp (90 deg) while oil pressure is reduced to 0. 

The next time I started the engine it ran with oil combined with water and this might have triggered this issue. This is what I believe to be the most logical explanation. 

When they first repaired it they got the crankshaft to a shop that resurfaced the journals to a new level and also they installed new bearings according to the new surface level. Basically the repair was done correctly but I am not an expert in engines, yet it sounds logical to me. 

What they say is that this engine (3.0 CRTE 218 hp) has some construction issues right from the factory and this is what caused the issue. But I find it hard to believe for 3 reasons:

1. Nobody would have made 170.000 km with the car with such a defect

2. Why this appeared only on a minor work like changing a gasket other than what I mentioned above? It also justifies the lack of any error code since no engine has water-in-oil sensors.

3. I would have found others with the same issue documented on forums.

I am stuck right now because they say the only repair possible would be a new crankshaft but they say it will do the same. If they know it will do the same it means they know what it has.

[Stevey Y]

Hi pretty much bang on with it will go again thats because you cant flush out debris with the engine still bolted in the car, if you look at the picture of the sump pan there seems to be no signs of massive water/oil emulsification, otherwise you wouldn't be able to see all those bits of metal, if you look at the other pictures the damage appears to be caused by oil starvation resulting in parts that would not normally come into contact actually getting together, the starter is a byproduct of trying to turn over a partially seized engine.

Think in your case it was just a series of unfortunate coincidences, I believe the oil pump started to fail and went terminal pretty quickly if you look at the milage that would be a prime suspect, also I have never been a fan of 15k services as they are a gimmick to make people buy cars, have you ever asked why oil turns black, yes its because of heat and other contaminants the main one being carbon from the combustion process therefore the longer you leave the oil in the more like grinding paste it becomes, my mate used to use old engine oil on the oxidised paint work on his old van, it bought the paint up like new and was very water repellent.

Regards Steve.

[shuffless]

Hi Steve,

I forgot to mention that the oil change was done 1 month before the event. It looked pretty clean. As for the oil color indeed diesels are not known for their cleanliness.

Given what you said about the flush ... when they did the repair they opened the engine to the very last part and cleaned it thoroughly. I do not think there was any part left unopened. I even have seen the entire engine taken apart so I trust them when they say they did just that.

As for now I do not know if I have to ask them to redo the job given the fact that we are in the same place as before or get a new engine. I am pretty sure the issue is similar yet the way the engine behaves is a bit different.

Thank you

[Stevey Y]

Hi, get another engine I am sorry but however well they stripped it and cleaned it there is no substitute for a hot tank/ pressure cleaned block and a compete strip down and inspection of every part, pistons rings bores, cylinder head, valves and guides.

In my early twenties a couple of my mates used to race cars so I sed to go to places like Burton engineering who were quite happy to show you around the workshop where the engines were rebuilt, their engine builders were fanatically clean and one explained to me that the slightest particle of metal in the engine could lead to component failure, especially in high performance engines, if I were you I would be looking at reconditioned engine with a nice fat warranty, job done.

Regards Steve.