New RS3 Loud ticking, and high vacuum under oil cap/revs??!!

[Tactical_ted]

Alright!

So 2000 miles on my 24 8Y.

Today I noticed a loud tick from the engine that I would say sounds like it's coming more from the accessory side of the engine rather then a specific cylinder.

Here is a video of that. https://www.youtube.com/shorts/YOSS-td1XrQ

But wait! While investigating I noticed that if I remove the oil cap it's under a LOT of vacuum!!! For me anyhow, and when the cap is removed the engine revs like it's getting un-metered air somehow. This is odd to me, never had a vehicle do this, and I would suspect some sort of PCV failure.

Here is a video of that. https://www.youtube.com/shorts/liNhgNwYHIg


Thoughts?

[NapalmEnema]

I think you are in your head about it, the engine is quite noisy - with so few miles are you SURE you're not just manifesting something?

[Tactical_ted]

Could be, but it's LOUD, I can hear it in the cabin and it sounds like a lifter going out on bubbas yard built LS powered lawn mower.

It also wasn't there before so that's also odd in my mind.

ETA: My Wife said, "What's that bad ticking sound?" as we drove to work today if that gives you an indication. LOL

[tegxsi]

The oil cap vacuum is normal and that's coming through the PCV system. There is no MAF sensor so there is no metering. These cars are speed density for the most part.

The ticking isn't normal. Take it to the dealer.

[Tactical_ted]

Will get it to the dealer.

Bummer!

[djn876]

The air is being pulled in from the hole you made by removing the oil cap, it's changing vacuum. It should have some vacuum, but not excessive vacuum. Could be a PCV issue. The clicking could be an associated solenoid that is failing. Definitely take to dealer to check out. Even though it doesnt have a MAF, the car has tables for air mass and all and will eventually give you a CEL if it's too far off from what the expected range is.

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[Def_Jukie]

What's the RPM range of the ticking?

[Tactical_ted]

All ranges. It goes to almost a half tick pace at idle, but as soon as you apply any throttle it matches a steady pace tick.

I started it this morning and it sounded real bad. Still real hard to discern if it is an individual area like valvetrain. It almost sounds like it's way down in the accessory area.

It was loud enough that I didn't want to drive it at all. Of course the dealer can get me in to look at it in 30 days.


Will continue to explore. I have found a couple other videos with almost the exact same sound.


Here is a video that has almost the same sound from another person. https://www.youtube.com/watch?v=-bMGGoAJUPg

[Tactical_ted]

New video. https://www.youtube.com/watch?v=06jQIc8cUvY

This is a cold start, and reduce to idle. Sorta sounds like a click/chirp now, and I am suspecting something down in the alternator area. I used a length of rubber hose against my ear and probed around and the alternator area has the most noise with the tick/chirp. Applying across the top the the cylinders I don't hear anything out of normal. It's 75% louder if I give it any throttle.

Anyhow.... Will update if I find anything before getting it to dealer in a month.

[Def_Jukie]

Mine sounded a little more like the one you linked from 2500-4500rpm, but instead of lifters it was rod knock which turned out to be a spun bearing (only 3300 miles on the car). Entire long block was replaced under warranty. Didn't have the squeaking sound though.

[djn876]

The chirp sounds like the belt is loose or is wet or something. Could also be a bearing that is bad. Did you scan the car with OBD11 or something to see if there are any pending codes?

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[Tactical_ted]

OBD11 on the way. Should get here today and I will see if it has anything coded.

[Tactical_ted]

Small update:

I started the car this morning and had a nasty shrill sound for about 1 second, then back to the loud chirp/click.

Looking around, it looks like the belt tensioner is not fully supporting the belt. Almost like the tensioner pully is backing away from the block. about 5% of the belt is not even on the pulley. This is starting to wear a mark on the flat side of the belt, and eventually I would expect damage the belt as the sharp portion of the pulley wears away at it.

I am starting to wonder if my noise is bearing failure in the pulley and or it backing out from not being tightened down.

Nothing for sure, but I find it odd it's not fully supported.

https://photos.app.goo.gl/bDFVvq1BHwYSXAWJ6


ETA:


It looks like the entire accessory belt is off the crank pully by one full tooth towards the block. It actually looks like it was installed this way as their is zero wear in that groove. This would also explain why the tension pulley is not lined up as well since the belt is fed to it from the crank pulley.

Hmmm.

So do I drop the wheel and remove the liner and fix, or let bozos at Audi do it. LOL.

https://photos.app.goo.gl/CAyDJnAuFBXxEbpT9

[Tactical_ted]

FIXED IT!

Couldn't wait. Dropped the wheel, Removed liner. Confirmed that the belt was one full rib off on the crank pulley. Removed tension, moved it over to center. SOUND GONE!

By the way, the BAD OMN plate is on this car for a reason.

So far since ownership:

Lost in transit for 14 days across country with no communication from shipper. Thought it was stolen
First 4 miles of drive time, I clipped the edge of a man hole cover that was sticking up, cut the tire, and destroyed the front right rim. 40 days for a new rim from Germany, and $2000 later for rim and tire it's fixed.
At about 400 miles I got a nail in the rear tire and barely made it to costco.

And now this is added to the list.


Yes the car is a BAD OMN, but I am not giving up on it, I love it. : )

[NapalmEnema]

Great find and self fix! Hope you're good going forward man - great one!

[robotvoice]

Wow good catch on the belt being off. That's pretty subtle unless you're really looking for it.