Looking at a buying a 2013 3.0T Q7 with 145k kms/90k miles on it and will be scheduling it in for a PPI this coming week. Unfortunately the dealerships are booking at least two weeks out at this point so may have to take it to an indie shop.

I contacted both the Audi dealer and an indie shop about inspections and asked about a compression/leak down test but both said they could do it however it's not necessary as any compression issues would show up as a DTC. It's my understanding that a compression test can show if there is some engine wear but maybe it's overkill? Long time Audi owner but I'm new to the 3.0T platform so not sure what's typical or recommended for this engine?

I'm going to have them scope the valley on the engine as I suspect there is a small coolant leak there. In doing some research, looks to be possibly the tstat, water pump, or one of the plastic coolant pipes that are the likely source of the leak.

Aside from the usual, anything else specifically I should ask the shop to look at/for? Obviously will have them look for other engine oil/coolant leaks, trans and diff leaks, etc.

Is there any test for the cam chain guide/tensioner rattle? Can a good shop tell if they're unusually noisy from a stethoscope, etc.? How long does it have to sit for the noise to typically show up? I had a listen on a stone cold start when I test drove the car and didn't hear anything that seemed abnormal but again not 100% familiar with the 3.0T so not exactly sure what I'm listening for. I'm used to the 2.0T which is a very noisy engine!

Thanks for any feedback!

 

If the service records are all up to date, and it only has 90k miles on it, you should just sit back and let the shop do their PPI (full inspection), which covers just about everything of interest and common failure points, etc. Looking in the engine valley for coolant or oil leaks is a good call.

Just remember these are forced induction engines and require premium fuel, so if gotta pay to play, better get exactly what you want. You don't want regrets going into your ownership of a used Q7...plenty of time for those later.

 

Generally all 3.0TFSI's rattle at startup, especially if they sit for a weekend and all the oil/pressure drains from the chain tensioners. The general working theory I have heard is if it doesn't quiet down after 2-3 seconds or so after start up I would start l would start to worry. This isn't anything very precise, but if it immediately starts to quiet down after startup it's probably fine. Leave the door open or window down as the insulation blocks most the sound from inside the car.
Replacing the tensioners is a massive job which requires the engine to come out.

 

I have a C6.5 with the 3.0 supercharged motor. Generally speaking most folks don't worry about compression or leak down for these motors. I didn't do one on a vehicle I purchased with just over 100K miles. As mentioned timing chain rattle is a common issue. You can do the rear timing tensioners in the Q7 and C6.5 without taking the motor out. The B8/8.5 S4 doesn't leave enough room between the back of the motor and firewall to do the work so it's common to pull the motors in those cars. Mine improved and is almost non-existent after switching to Liqui-Moly oil and doing a ceratec treatment. For the coolant leak, other things to consider are the PCV failing, intercooler bricks failing. Taking off the supercharger can easily be done, but is definitely not part of a PPI.

 

+1 on using better oil and additive products. You should plan on doing a full reset if you buy it.
We had two noisy TDI's running on the 'recommended oils' by Audi/Castrol, etc. Did proline oil flush/purge by Liqui Moly, bottom drained, Liqui Moly Ceratec additive goes in first, then top it up with Liqui Moly 4200 5W30, which is VW 505, 507 oil spec rated. The Ceratec additive (add at 30k mile intervals) is mainly for efficiency and wear reduction. You don't know how quiet and smooth an engine can run until you pour in the Liqui Moly oil. I'm also seeing the best mpg numbers I've ever gotten since owning these cars, since switching over to Liqui moly products. As you are in Canada, and it's a gasser, you might peruse the Liqui-Moly fluid finder page to see what is recommended for it.

 

Thanks for all of the feedback! Still waiting to try and get the Q7 in for an inspection. Good shops are slammed these days.

Good to know about the Liqui Moly. I have always ran Mobil-1 0w40 in my other Audis, from what I gather Mobil-1 and Liqui Moly are very similar performance-wise. If I remember correctly the only reason I haven't run Liqui Moly is because it's harder to find a 0w weight. In Canada with a cooler climate, my reasoning is that the 0w helps lubricate quicker on cold starts. Interesting that Audi specs both Mobil1 0w40 and Liqui Moly 5w40 as approved oils for the 3.0T. I did a deep dive into motor oils years ago as part of a fluid engineering course I was taking. Can't remember where Liqui Moly scored but Mobil 1 came out on top in nearly every category that relates to engine protection.

Curious about the Ceratec additive. I have used BG products which sound similar, hadn't heard about the Ceratec. Also curious about the Liqi Moly Molygen oil, anyone using this? Sounds like it contains a similar additive to Ceratech. It specifically states that it prevents the formation of deposits, wonder if that would help prevent carbon buildup on valves.

@'10Q7TDI_Prestige' You mention 5w30 4200, I assume this is for the TDI engine?