Timing chain rattle on cold start. Quick fix, but not a fix.

[seanB7]

When I cold start my b8.5 S4, I get less than a 2 second rattle coming from the back of the engine. When the of front the car is raised higher than the rear... No more timing chain rattle on cold start.

Try it, let me know.


The Back Story:
Half of the time when i start my car in the garage before work I get about a 1 second long obnoxious timing chain rattle noise coming from the rear of the engine. The noise is definitely timing chain rattle. The garage floor is cracked and not 100% level. I get to work at 7AM, leave for lunch at 11:30, then leave at 3:30. The parking lot is slightly sloped for water drainage. If I back into a parking spot and the front of the car is higher than the rear of the car; I never get timing chain rattle. If I park forward in the parking spot where the front of the car is lower than the rear, I will always get the rattle after several hours of being parked.
I have only had the car for 2 months, it's summer time, and the engine isn't super cold like it will be in the winter time. This is my daily driver. The car has 63,000 miles. Oil changes were done every 10K miles at the Audi dealer before i purchased the car 2 months ago. The last oil change was 3,000 miles ago. The oil is full based on the dipstick measurement and the MMI measurement. I've now been parking the front wheels on 2X6x10" wood blocks in my garage and have not had any rattling noise in the past 5 days.

Am I crazy... Probably. If you get the cold start rattle, try this.
Also the TSB, if you haven't seen it https://www.carcomplaints.com/Audi/S...oogle_vignette
https://static.nhtsa.gov/odi/tsbs/20...20672-9999.pdf

I will be doing the tensioner at 100,000 miles when i get there

[LowKeyLoki]

This all has to do with the oil pressure to the tensioners and it draining out, this issue has been discussed many times and the consensus is it is nothing to worry about till it gets to be over 4-5seconds on start up. Plenty of people have a 2-3 second rattle on cold start and have no issues (me included). You can check the chain stretch via VCDS. I wouldn’t touch the chain or tensioners till the rattle becomes persistent or chain stretch is evident. And btw 10,000 mile oil changes is WAY too long, these engines oil should be changed every 5k miles.

[Nillious]

When I got my 13 s4 around your mileage I was sick to my stomach when I realized it rattled like this. I was really worried and tried everything. I just hit 150k today and it still rattles just like always. Mine will rattle warm as well if it’s off for more than about 45 minutes.

The oil drains down out of the heads and oiling circuits in the valley. It’s simple gravity. The lack of check valves or anything to control this leaves the heads and oil circuits full of air that needs to be pushed through all the passages. During this time is when you hear the rattle. There are check valves that can be added to keep the top end full of oil. Many have added them and said the rattle is so little you almost don’t even notice it. I’ve never gotten around to it yet but I plan to add them soon.

[BrokeBichB8]

Somebody (cant remember where) noticed that certain filters have a shorter height and allow loss of oil pressure when off. That combined with a good quality oil ( LM sucks imo) and the check valves, regular changes and even slight timing chain rattle will be fine.

Its not limited to our V6 only. I had a newer 350z and that thing would rattle hard on start up, every start, but it got 60,000 miles put on it all the way to 130,000 total without a hiccup.

[Nillious]

I’m a motorcycle tech for a living. A lot of European bikes rattle on startup. Ducatis and triumph are known for this. Straight hydraulic actuated chain tensioners with no ratcheting pawl and not enough spring preload tension to support the chains without oil pressure. This is the exact situation with the Audi tensioners. The preload springs get weak and no longer support the chain without oil pressure.

[PenttisHSR]

Here's a Link to that thread FWIW.......... https://www.audizine.com/forum/showt...rainback-valve

Here's the related TSB......... https://static.nhtsa.gov/odi/tsbs/20...16616-9999.pdf

[siffer]

I just bought my second b8.5. It did have the rattle for a couple seconds. I immediately did an engine flush and fresh oil. Added a bottle of ceratec and no more rattle. Even after a week of sitting.