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This was supposed to be a quick update but ended up being a longer video with crisp details I believe most of you will find useful. It's about my dying 2016 Audi A7 with Audi's flawed and defective 3.0 TFSI V6 Supercharged Evo EA837 engine aka CREC. Audi's A6, Q7, S4, S5, SQ5 have the same engine. Stay away from anything with this engine.
Chapters
00:00 - Preview
00:45 - What's happening and the plan
06:54 - Oil on the ignition coils
14:06 - Loose and messy spark plugs
22:32 - Cleaning and soaking spark plugs
23:00 - Cleaning spark plug wells
23:35 - Changing oil
28:48 - Oil filter adapter torque explained
29:50 - Audi genuine engine oil stock
30:30 - Oil dipstick
31:05 - Changing air filter
32:48 - Vinegar and spark plugs
37:57 - Ignition coils
40:22 - VCDS results - Fault codes check
48:09 - Compression test results
50:37 - Liqui Moly carbon cleaner injection
58:42 - Test drive
59:11 Outro
Audi 3.0T CREC Supercharger Intercoolers Replacement Guide
This is something I did in the past that I am sharing now. I hope it helps those in need for this kind of information I did not find online about Audi 3.0 TFSI Supercharged CREC Engine when I needed it.
After I replaced the spark plugs, the throttle body, the MAP sensor, the MPI injectors and the FSI injectors because cylinders 5 and 6 were misfiring in my Audi 3.0 TFSI CREC Supercharged Engine, I decided to replace the intercooler on that bank because a leaking intercooler can cause misfires too. I purchased one intercooler and replaced the one for bank 2 serving cylinders 4, 5 and 6, but then I got confronted to a broken bleeder screw on the intercooler for bank 1. I damaged the cooler trying to remove the broken bleeder screw bits so I was obliged to order another one. Cost with shipping, tax and customs for both coolers was around $3,300 not including the bleeding tool and the replacement 034 Motor Sport bleeder screws.
Replacing the intercoolers or charge-air coolers did not fix the misfires. It turned out the cylinders have lost compression and the engine needs to be rebuilt or replaced.
Chapters
00:00 - Preview
00:37 - Removing Bank 2 Intercooler
09:10 - Cleaning Carbon in Supercharger Bank 2
15:37 - Installing New Intercooler for Bank 2
43:02 - Broken Bank 1 Bleeder Screw, Damaged Cooler
43:44 - Cleaning Carbon in Supercharger Bank 1
44:19 - Installing New Intercooler for Bank 1
44:24 - Installing 034 Motor Sport Bleeder Screws
46:46 - Supercharger Looking Brand New
47:53 - Bleeding Intercoolers
FWIW I think that the key to keeping these 3.0T engines (at least my iteration -- MY /15) going without too many surprises is that somewhere between 80-100K one must be ready for a bit of a "refresh". Cooling system attention - water pump, thermostat, crossover pipe under the supercharger, renew coolant. While in there with supercharger off, check it and ancillaries thereto for any leaks, etc. and might as well do a carbon cleaning. Perhaps new coil packs and spark plugs at that time. I also think that preventative replacement of the PCV system (not terribly expensive) is a good move. As well, possibility of motor mounts and exhaust flex pipes needing attention. Once those items are addressed, good chance the next 40K miles will be smooth (with a bit of luck). This won't be exactly cheap but compared to disbursing 65K+ for a new A6, it is peanuts. Having said this, despite the fact that some of our compadres (Valpo, I'm talking about you here) have been able to run these cars to very high mileage, I will move on to something newer once mine reaches 120K miles or thereabouts. We are not dealing with a Honda/Toyota of the 90s through the mid-00s -- the A6 is a much more complicated, tech-laden beast that can become very expensive to keep on the road beyond 120K miles. I neither have the wrenching skills of Valpo nor the stomach to deal with major engine issues or run the risk of MMI failure and a myriad of other possible problems. I'm lucky in that I don't drive the A6 more than 6-7K miles/year so at 75K miles I can easily go another 6-7 years before reaching my magic 120K limit. It helps to have an excellent indy who is good with FCP Euro supplied parts and is far more reasonable in his hourly rate than the dealer.
An undetected stuck open injector will eventually destroy a DI / MPI engine. Constant fuel spray in one or more cylinders will wash oil off the cylinder walls and excess fuel will push past the rings and accumulate in the engine oil. This will contaminate and dilute the oil and force the PCV system to extract very high VOC content from the block. A stuck open injector fuel wash will wear the piston rings and score the cylinder walls and eventually cause irreparable low / no compression.
Recommend periodic checks for stuck open injector, perform injector service for higher mileage engines and consistently use Tier 1 high octane fuels.
Highly recommend a periodic quality DI / MPI fuel additive to a tank of fuel as this could clean a stuck open injector and return it to normal running state.
I appreciate your valuable inputs. However I would like to bring to your attention that the original 3.0 TFSI you have in your pre-facelift C7 is not the same that came with the facelift C7.5. The 3rd generation 3.0 TFSI with "direct injection only" in your original C7 seems to be a robust engine as pointed out by a lot of owners despite a few issues here and there mostly with the coolant pump and thermostat.
The 4th generation 3.0 TFSI "CREC" with both direct injection and port injection is the one I unfortunately decided to go for and is the problematic one. Data about this engine is not broadly available yet as these cars from North American model year 2016 are pretty much still new in the used cars world. I was surprised to find ZERO information whatsoever about this engine when I needed to replace my oil separator. I ended up being the first person on YouTube to share detailed information about the internals of this engine and the first DIY video guides. That video above about the intercoolers in the supercharger of this engine is the first ever.
So yes, it seems your original C7s may not have these issues but know that the C7.5s are a totally different story. The majority of people do not know this. I did not know this and I based my purchase on the positive reviews of the original C7, thinking the C7.5 would be even better but alas!
Again, the 3.0 TFSI in the C7.5 is VERY DIFFERENT.
Gen 1: 3.2 FSI from 2004 (C6 A6 from NA model year 2005) Gen 2: 3.2 FSI from 2006 (C6 A6 from NA model year 2007) Gen 3: 3.0 TFSI from 2008 (C6.5 A6 from NA model year 2009, C7 A6 and A7 from NA model year 2012) Gen 4: 3.0 TFSI from 2014 (C7.5 A6 and A7 from NA model year 2016) - Problematic. Same in Q7, S4, S5 and SQ5
NA = North American
We are saying similar things. MPI = Multi Port Injection is a generic term for modern engines that uses both Direct Injection and intake Port Injection such as the CREC.
Red is the high pressure DI system and Blue is the low pressure intake injection system.
The combination of the two injection types helped resolve the prior generation Direct Injection engines of the nuisance periodic intake port Decarb Service.
The single biggest downside to DI including the DI portion of MPI is the risk of a stuck open injector that will constantly spray fuel directly into the combustion chamber. There are no obvious driver warnings so this failure mode can easily go undetected for a long time.
While there are obvious enhancements to the CREC from it’s 3.0T predecessors, the CREC shares same replacement part numbers back to 1st gen 3.0T for many parts including oil separator, DI injectors, pistons, etc.
This injector set is from a Tier 1 premium fuelled DI CCAA 3.0T removed at 65,000KM. Note the prevalent carbon buildup and how it is trying to close some of the fuel outlets. Can see carbon deposit accumulation where chunks randomly separated from the tip surface which means they were randomly flying around the combustion chamber and, if large enough, could land on the face of the cats. One injector was found to be stuck open and was resolved by a cleaning service = saved the engine from catastrophic failure.
There is no fool proof guarantee other than specific diagnosis for stuck open injector such as monitor LTFT, monitor high pressure fuel system bloom amplitude and duration after hot engine shutdown, sniff test, compression test, bore scope cylinder walls looking for scoring, etc.
Periodic use of a high quality fuel cleaner additive can help avoid long term leaking combustion chamber injectors for any brand any model DI / MPI engine.
I agree with most of the things you said. Preventive maintenance is a must. Unfortunately, the dealership will not do this and will maintain the car with the minimum expense possible, resulting in the car being a complete garbage after warranty has expired. Me and you are the rare ones who know they should perform these things. The majority of owners just take the car to the dealership every 10K miles for oil change and scheduled maintenance. Once the car is passed over to the next owner, crap hits the fan. Ouch!
However, I am sorry to contradict you on this one:
Originally Posted by AudiAllTheWay
While there are obvious enhancements to the CREC from it’s 3.0T predecessors, the CREC shares same replacement part numbers back to 1st gen 3.0T for many parts including oil separator, DI injectors, pistons, etc.
Nope! All the parts you cited are completely different. Yes, completely different. Different oil separator, different DI injectors, different pistons. The engine block, the cylinder head, the breather system, the vacuum system, the coolant system, the supercharger, the intercoolers, the chain system, the camshafts and adjusters, the valve system, a lot of things are completely different. I can't think of one single critical component that was moved from the Gen 3 to the Gen 4. Some coolant pipes and the expansion tank maybe?
I have not checked every part you listed but I think you’re referring to part number updates over time, so yes I agree the earlier 3.0T engines had earlier part number revs vs CREC.
The example parts I listed have dealer currently available part numbers that are fully backwards compatible to generation one 3.0T.
For example AFAIK the current part number for the CREC oil separator is 06E 103 547 AC and is backwards compatible all the way back to 2009 A6 3.0T among several other 3.0T models, etc. Interesting to note the the alpha characters after the first nine are the rev number and the Audi dealer should be selling the latest available rev. If you ask for an oil separator for a CREC or a CCAA today then the Audi dealer will sell you the exact same part for both engines.
08-13-2023, 02:50 PM
