audijim113

History of tensioner clatter with four A8's over last 9 years

1998 A8 purchased with 125 K miles in 2007, now 190K miles never clattered. Wife currently drives this less than 5,0000 mile / yrs. PO had extensive work done to it. (heads off for gasket leak and more), however, documentation of all repairs does not show chain tensioner replacement.

Previously owned 2000 A8L bought at 220K miles clattered loudly bad and I had one side tensioner replaced after driving 50K miles. When sold at close to 300K miles, it was still relatively quiet.

2005 A8 with 250K miles sold at 330K had no clatter did give me headaches with other problems.

My current ride, 2006 A8L did not clatter when bought in 2017 at 130K miles. A year later, at 145K miles, it's geting louder. Sometimes, I'll hit start button, quickly turn off, repeat a couple times which gets oil up to adjuster. On third start, it's quieter. I'm not sure if this process is beneficial or detrimental.

Aside from the history, my question is whether choice of oil makes a difference. I'm using Mobil 1, synthetic 5W30. It doesn't seem to make any difference in the clatter even the next day after a fresh oil change. Clatter is only a couple seconds and more than one commentary says it's normal, not to worry but it bothers me.

I did have an old Dodge once in my youth with a rod knocking, which I put in a bunch of STP until it threw the rod. I"m not planning on putting any goo or molasses in my Audi.

MP4.2+6.0

Per a long string of prior threads where this comes up from time to time, can be tensioner, but can also be the antidrainback valves in the oil circulation system for the heads. Few seem to know about these. First dealt with them when by 2.8L 168HP 1996 A6Q would occasionally squeal like a pig for no good reason. Turned out to be those. If they stick open, oil can drain from heads after shutdown when not intended, and of course can then lead to start up added noises. Low failure rate, but likewise I suspect even many mechanics may not know they are there.

audijim113

Looking at the long thread of 4.2 engine noise, I remember when i had the 2000 A8 reading some similar back in 2014 when I had the chain tensioner/adjuster replaced on that car which fixed the rattle. Your comments about the drain back valves makes sense as when I start-turn-off my 2006 a couple times in the morning, it must be getting oil pressure up there as it is quiet on the next start. Might sludge in the valves is the problem.

Reading the thread, there were a couple comments about engine flush. Does that make sense? Seems like a lot simpler than replacing the anti drain valves which I'm guessing require quite a bit of wrenching.

As indicated, I have used Mobile one 5-W-30. The previous owner also used the same for 70K or so he owned it. Checking 502 specs I see Mobile one is on the list. Any advantage to using 5-W-40 instead of 5-W-30? I live in Michigan and it tends to get pretty cold. Of note, I picked up the car in March of 2017 and it was quiet for a year and a half until it started to get colder in October.

Any thoughs appreciated

uberwgn

Jim, the "Mobile" 1 5W30 product you are using doesn't meet the VAG spec.

The 502.00 spec oils tend to be thicker than many of the other products on the market. I can't see any downside in using the oil recommended for your car.

The VAG oils are all-season/all-climate.

ScottCNelson

if that's what you want to use, but Mobile 1 ain't one of them

Mister Bally

FWIW, I've been using 5W-40 in various brands: Valvoline, Lubri-Moly, Total, Pentosin, Volle Synthetic, Castrol in both "regular" and the newer "super" versions. All have the VW 502 designation.

No noises and I've done 23 or 24 oil changes in it so far (2004 model).

I'm also in Michigan and even in the coldest winter mornings, the engine cranks fine and starts right up.

MP4.2+6.0

Yes, you can try an engine flush product--the type that goes in the oil for 20 minutes or so and then you idle engine and then drain it.

Mobil 1 OW-40 is the one that meets the VW502/505 spec. Well regarded oil. The Mobil 1 5W30 as sold in USA has never met the spec. For any of the bigger brands like Mobil 1 or Castrol, you have to look very carefully to see if they are 502/505 compliant. They often include the words "European Formula" on the front of the bottle too.