Jayo16

Hi All,

New member here...quick question about a recommendation from the dealer at my 65k service last August.

They said that I really need to have my intake valves cleaned due to carbon buildup. For $1500...

I checked the forum and see that this may be a problem on the 3.0L models, but not seeing anything about the 2.0T.

Is this legit? I have a 10-year extended warranty through Audi Pure Protection Plans (Platinum) and see that repair or replacement of intake and exhaust valves are covered, but not if due to lack of maintenance. I've had every required maintenance done via Audi Care. Since this was recommended, and if I don't do it and they needed replacing, do you think that would be cause for it not being covered?

Is this a problem I should be concerned with? I'm at $74k now.

Thanks very much-
J.

silver_tt

All DFI engines suffer from carbon build up. But my 2014 Q5 2.0T has 105K miles on it and I scoped the intake a few months ago and it was crusty but nothing to obsess over. My advice would be to use an oil with a low volatility and to not worry about carbon cleaning until the next time you have the intake manifold off anyway, unless you're getting misfires, terrible gas mileage, or have some specific reason to believe that your carbon build up is really bad. Our engine has injectors that are more advanced than the earlier models among other changes.

turbo510

First, I doubt that lack of carbon cleaning would have anything to do with your warranty 'repair or replacement' of intake valves. It might be a recommended by the dealership for extra service department income, but the worst thing about carbon on the valves is restricted air flow, in my opinion.

Our '09 3.2 needed the intake manifold removed to replace a leaking oil separator/vent valve assembly. The shop owner then called me to come have a look at the valves, and they were indeed pretty nasty-looking. They had a walnut-hull blast and vacuum setup, so I agreed that the cleaning might as well get done while they were accessible. I don't remember the charge for it, and don't really know if there was any tangible improvement other than perhaps power at WOT. The car ran well before and well afterwards.

stash64

I had my Q5 at the local Audi dealer for an alignment recently and asked if they had an intake valve cleaning service. I was a little surprised that they answered "yes" and the service advisor thought it would cost about $1k for my 2.0T. It is the "walnut blast" service but they also follow it up with a chemical cleaner. $1000 seems reasonable but I intend to get a formal quote first. Has anyone here had the walnut blast service at a dealer or otherwise?
I am seriously considering a stage 1 engine tune this year and my thought is that cleaning the intake valves would help to make the most of the tune. I've already installed a larger intercooler and other intake mods to improve airflow.

silver_tt

Yes but not on this car. Walnut shell blasting is the best way to clean intake valves for sure. It gets them so clean not even sure why you need a chemical after. It's pretty easy to do, just need a "fitting" that matches the intake port and be sure they are closed so you don't get a bunch of walnut shells in the combustion chamber. As I recall your engine is low mileage so I doubt there is a lot of carbon buildup but it is very easy to stick a borescope in the B8.5s intake manifold and see (there is a sensor that unscrews). If you are worried about carbon build up you should use a low volatility oil (check the NOACK volatility). Personally I would not bother with walnut blasting unless I have reason to take the intake off or unless I think there is a problem; if I ever have to do that I will walnut blast it for sure.

stash64

Which sensor needs to be removed... is it the intake temperature sensor? I might give it a try if it is fairly straightforward. I do have a borescope that I used with my laptop for peering behind walls.

What oils would you recommend ? I did a quick search for NOACK ratings but did not find much. It does not look like there is a site that keeps track of volatility scores. I have mostly used Castrol Edge 0W-40, Mobil 1 once or twice, and I just did my most recent oil change with Liqui-Moly 5W-40 (LM20232) for the first time. The Pennzoil Platinum has piqued my curiosity. I imagine that it has very low volatility given that it is made from natural gas.

silver_tt

here is a picture of the sensor I am talking about. Usually for most oils if you search you can find a spec sheet with the volatility, there is a ASTM standard test to measure it

stash64

Yeah, that is the temperature sensor. To the right is a vacuum line that is also easy to remove. Would that not be a better option since it is centered on the intake?

silver_tt

I did not try the other line you are referring to but the one I showed provides easy and unfettered access to get a borescope in there. I now have a nice articulating head borescope but it worked just fine at that time even with a cheap unit. That was maybe around 80K miles, I did have some carbon buildup on the intake valves but it was not that crusty.

stash64

We're you able to see all 4 ports? If not, I think just seeing the one directly opposite the temp sensor would be a good representation of how much carbon crud is on all the intake valves.