Posted earlier on Audizine. Some may remember in an earlier post on RS5 engine issues I mentioned I had a 98k mile engine that was seized, I bought the car that way and the good news is I am installing a 25k transmission along with a 26k engine. Car is getting a refresh from the ground up.
Down to the nitty gritty. With the crank tool installed the engine would turn over with a 1/2" drive breaker bar at a steady but difficult pressure. I checked the valve train and all looked good. Good news is with that mileage all of the cam chain guides looked like they were holding up real well…better than previous Audi designs. Finally pulled the oil pan an lower assembly apart and found that #4 Crankshaft rod journal which holds #4 & #8 (two back cylinders) Rod big ends were spun. Due to the striations and damage to the bearings I would say most likely it was due to some kind of oil contamination. I’ve got the records for the car and it has pretty much had Audi dealer servicing its whole life, so not necessarily the best oil but at least meets Audi specs.
It’s a very complicated engine assembly and it was interesting to pull it apart and see how it was built/designed. I am pleased that I’m almost positive the failure was due to oil contamination of some kind and not to any design flaw in the engine.
So change your oil and filters regularly, better to do a little more often than Audi’s recommendation and use a top quality oil. Regular Air filter changes would be good too and be careful of any dirt or contamination getting into the engine.
Oh wow that looks a mess ! Good to know that the engine has no issues and as long as regular oil and filter changes are done all should be ok. Glad you got to the bottom of the issue and can see why this has happened. Good work 
Out of interest what oil do you use or recommend ?
Wow thanks for sharing this information.
It would be interesting to see other motors and see what there bearings look like. This isn’t very common is it. I know there are a few handful of things that the RS5 needs to keep it running well and as the miles stack up for many owners it would be good to know just now careful they need to be with the oil
I used Redline 5w-40 in both of my Audi’s and my Cayenne Turbo and my oil analysis (blackstone) comes back great, I usually change the oil around 6~7k miles.
I was a little nervous as there doesn’t seem to be a lot of high mileage RS5’s out there yet and there have been some failures in a couple of threads on Audizine. The early failures on warranty and even the ones that were out of warranty but engines replaced at the Audi dealer are all suspect as Audi will not tell you what failed. In most cases they send the engines back to Germany for analysis. Hopefully early failures in the CFS series have been cause for Audi to redesign/improve any suspect part. Many parts do have later part # revisions so hopefully those are improvements. The rest of the bearings in this motor looked fine. I need to study the oiling system , maybe the back of the engine gets oil (contaminated?) first? Actually, I’ve only checked the Rod (crankpin) bearings so far, it will take splitting the two block halves in order to remove the crank and check out the crankshaft bearings, at least the rear two for sure.
But like I said, use a top quality oil (8500rpm Redline) and change it often ( a lot of shearing at 8500+ rpm). I was worried about the Cam chain guides and they were all in great shape at 98k. Only issue I see is having to do the Carbon cleaning which is a pain. Probably want to change the oil the first drive after the carbon cleaning, especially if using a chemical cleaner as it will wash debri into the cylinder and some will get past the rings.
Great post I can agree more. I found myself working overtime to convince people that you shouldn’t put the oil service to 10k and that oil just isn’t oil.
The list of issues with the RS5 motors include the cabon clean and then the injectors needing to be replaced. Good of you to help put this out there. I don’t know if it is something that makes sense or that you care to do. But it might not be a bad idea if your interested in listing a few of the stock motor reported failures in this thread. A deep catalog of such a thing can really help the platform.
This is really fascinating. Why the two adjacent cylinders, though. Doesn’t that point to low oil potentially or diluted water fuel contamination?
If it were random cyliders, knowing this, I would do an engine flush from time to time.
Audi, at least here in Europe, exclusively use the oil extraction using a pump and I dont know that they will make damn sure to drain it properly. Definitely keep your oil level in the upper half I guess also.
There is a guy on the Facebook A5/S5/RS5 forum that just reported he had a failure at 80k miles. His was Rod journals were 3/7 & 4/8. He doesn’t know what caused it but had a new engine installed by Audi. His had much more damage than the motor I had in the way of metal shavings throughout the engine plus the extra crankpin journal (3/4).
80 and a motor replacement. That would have been CPO car…
Do you have a good idea on how many failures total there are.
There would be good cause to keep sending out oil samples to blackstone and lower the oil change interval.
I’m with you on Blackstone oil analysis for sure. If you search on Audizine there have been a few failures. I know some of them were at low mileage. Other than having the records and knowing the dealer service on the engine I pulled, I don’t know what oil the dealer was using and/or how the car was driven. Car is in good condition but the whole engine compartment was very dusty but it had clean OEM air filters and the OEM oil filter. I think it was owned by a stripper as there was some glitter in the car and a fairly strong perfume scent 
Is it fair, though, to say there is a slight discoloration indicating a bit of excessive heat. Then, given the fact that the model burns some oil, and probably a bit more at higher mileage, no manual dipstick, to put it down to low oil pressure?
Yes there was a slight discoloration on the Rod big ends. Could be some water dilution but from the longer scraping looking damage on the bearings and the crankpin it appears more like oil contamination. Why the back crankpin? Maybe it is at the tail end of the oiling circuit. Anyone have a RS5 oil gallery diagram? And I corrected my description of the guy on Facebook’s engine damage to correctly read cylinders 3/7 & 4/8.
Audi might be keen to look at the engine–have you asked them about goodwill? I think it is just at the mileage where they stop caring about/guaranteeing dealer serviced cars.
Rs4 b8.5 engine taken apart the oil jets are visible there.
I use 7zap! to look at common parts between the rs5 and other VAG cars or order parts–I was thinking about the oil pump and wanted to check the record of it.
Maybe Ape or someone who knows will chime in here but I had heard the R8 V8 was closely related to the B7 RS4 4.2 and our motor was closely related to the R8 5.2 V10 obviously with 2 less cylinders? Anyone?
So I just confirmed the RS5 piston is the same as the R8 5.2 and uses the same ConRod big end bearing. Conrod itself is one suffix off on the part # so possibly the same rod too.
Edited my last post. Yes, I also noticed several engine parts shared with the r8 5.2.
It seems the R8 has the same service intervals as the long life audi service–Yes, no audi r8 driver will reach that based on the computer calculating the interval using driving style; still, the long life rarely tells you to change oil within 10,000 miles.
I learnt that extracting the oil is fine if you top up with fresh oil when nothing more comes out of the pan, then resume emptying until the oil that comes out is clean and new. I wonder, though, if little pieces of metal would still be trapped at the bottom of the pan or suspended in the oil.
I am old fashion when it comes to the oil drain. I pull the plug and let it drain for a good hour or two and I also use a magnetic drain plug. I use the magnetic drain plug on every vehicle I have. On all vehicles there is always a small amount of super fine metallic slush that needs to be wiped off. I do have the advantage that I have a 4 post lift in my shop so raising the car is easy for oil changes. I use the magnetic drain plugs from ECS tuning and also use them for the DSG.
Gonna be disciplined keeping the engine bay cleaner, particularly by the lower intake manifold gasket as it seems to be a place where dirt and gravel collects. I guess though that was more or less gravel that must have got it somewhere along the intake.
So yes, the RS5’s engine has more in common with the R8 than with the RS4. There are aftermarket rods/pistons for the R8 which should work with the RS5’s motor. I’d make sure the cylinder walls are not scored heavily due to oil contamination.
I think those bearings are done!
The V8 M3’s had major bearing issues, with many cars requiring new bearings in as little as 40K miles. I’m just about to turn 70K and the motor is still going strong.
If your motor is consuming oil, take a good hard look at the PCV system. I was consuming oil for a while and did have to replace my PCV valves. I think they go bad and contribute to oil consumption long before they start to “whistle”.
I’ve had, literally, zero oil consumption since my last oil change using the Motul Sport (and new PCV valves). But…consumption was greatly reduced when I switched back to Motul Specific from Liqui-Moly.
Speaking of oil, the low engine oil warning light turned on in my RS5 and when I checked the owners manual it and it recommended Castrol Edge which is easy to get. How come I never hear anyone using it? I have about 33k on it. I have Total oil in my car now. Which oil should I be using?
I think, if you can get it, you will be happy with 0w30 502/507 (I think) Castrol edge titanium. I go with that to stick with the same oil, but the titanium 5w30 LL is a lot more easy to come by here so I am running that more often than not.
The key is oil sample tests, to have this question answered. Otherwise, we will to wait for, God forbid, engine failures.
I can tell you this much though: this side of the pond Castrol (BP) is common in general. The only other oil you, although only rarely, get from Audi here is Mobil1. Most people here don’t know how to change their own oil and go to audi for the 600 USD oil change every 2 years or 20.000 miles.
Here is the point: I have rarely heard of engine failures here in Europe of the b8(.5) rs4 and RS5s. The same applies to the R8 with the same intervals. Based on that I would say that the titanium oil is doing a good job. Once I get a country where people take more notice of oil changes I will have the samples taken between oil changes, even.