Guys - I've got 150k on my car and about 10k ago it started to rattle on start-up. Only 1-2 seconds and then it would go whisper quiet. Everyone I talk to says 'no big deal, they all do that eventually'. I'm not an engineer, but I know vanos is metal on metal, and that cannot be good.
My indi shop races BMW and I've taken all my BMW's there for years. Anyway, they confirmed it was NOT guides, and was most likely vanos rattle. They suggested a BG oil treatment (Yes, I've heard the commercials on the radio for years and think they're crap), so I did that and then put in 10w-60 Mobil 1.
It has been whisper quiet ever since.
I'm not saying this is a magical solution. It might be bad in the morning; who knows. Just sharing my experience w/ a higher mileage motor with vanos rattle.
Good for now....
Aaron
Current
'13 528i xDrive M-Sport
'00 Audi 6 4.2 Sport - 6 sp conversion - 155k
'12 Audi Q5
'08 Silverado Duramax LTZ
Past
'10 - 128i Convertibel - sold
'01 740i Sport - sold 155k
'95 M3 Coupe
'95 M Roadster
'07 328i - sport, convenience - sold 176k
'95 S6 - raced and sold
'00 528iT - sport - sold
'95 993 C2-sport - sold
'06 M3 Vert - sold
'10 TDi Jetta Cup Edition - totalled
'02 996 Cab - sold
Please report back. Not knocking BG oil treatment (I don't even know what it is). But, could it be just the oil change? Since I don't know how vanos is put together/works, I am looking at this from a broader lens maybe.
Anyway, congrats to you!
First of all, if it rattles a few seconds at start up then goes away, you might want to look at your oil housing filter check valve. It suppose to retain oil after you shut down the engine. That few seconds of rattle is probably time it takes to prime the oil thru the system.
Secondly, 10w60 is way too think for your 740.
Just my opinion
Sent from my VS995 using Tapatalk
It’s your timing chain guide tensioner.
I have one that rattles only after sitting for a couple of days. On warm start, no rattle. I've changed out the tensioner already, for good measure. I've heard that the Castrol is better than the mobile 1 for vanos rattle. 0w40 ??
Current
95 e31 840 Ci (Auto) Orient Blue 61k
11 e90 328i Space Gray
18 F15 X5 35i XDrive White
Past
00 e38 740 i (Auto) Titanium Silver
94 e31 840 Ci (6 speed conv.) Avus Blau (This car was Awesome!)
03 e46 325 Ci (Auto) Jet Black
91 e31 850i (Auto) Diamond Black, Yes, two!
91 e31 850i (Auto) Diamond Black
00 e39 528i (Auto) Jet Black
92 e36 325i (Auto) Laguna Green
I bought an e38 on May (M62tu).
The VANOS was rattling a bit and I did not know what oil was used on the last service.
Anyway, on October, I did an oil change and used Mobile1 0W40 and since then rattling is louder at start up.
The problem comes from VANOS piston seal O-rings: http://www.beisansystems.com/procedu..._procedure.htm
It's the next big thing I will do on my car.
Last edited by Shnalla; 01-16-2018 at 04:08 AM.
edit: I thought the VANOS rattle was the diesely clunky sound at hot idle, and the start-up rattle was timing chain slack.
~5 years ago my indy at the time also suggested thicker oil M1 10w60. It was quieter for a week or two, then back to normal every 3 to 10 starts, no pattern. I changed the tensioner and that has made the most difference, but still happens now and then. I also did a sea-foam treatment at one point another year later hoping to clear those check-valves if that was the issue. Still get it every now and again, but not very frequently. ( on my e39 )
~1.5 years ago I changed the tensioner on my e38, and it made no improvement at all. The e38 has 40k fewer miles.
I suspect that the frequency/severity of the start up rattle has something to do with how much timing guides have worn, and how much extra slack is there.
M1 5w30 every ~8k in both cars as long as I've owned them, except for the above mentioned trial. Going to try 5w30 high-mileage in the next change.
Last edited by agentrnge; 01-16-2018 at 10:38 PM.
Thanks for the history, Agentrnge.
I'm still in 'quiet mode', but we'll see. There has been a comment or two about 10w60 being too thick. Living in SoCal with car garaged, I figure I can gamble for one change cycle. If it comes back a tensioner might be in the works.
Any clue on the cost of vanos rebuild to get new 'o' ring seals installed? This doesn't look like something I want to tackle myself. Ideally at 150k miles, I need new vanos seals as well as chain guides, but I'm sure those repairs add up to a lot of $$$
Aaron
Current
'13 528i xDrive M-Sport
'00 Audi 6 4.2 Sport - 6 sp conversion - 155k
'12 Audi Q5
'08 Silverado Duramax LTZ
Past
'10 - 128i Convertibel - sold
'01 740i Sport - sold 155k
'95 M3 Coupe
'95 M Roadster
'07 328i - sport, convenience - sold 176k
'95 S6 - raced and sold
'00 528iT - sport - sold
'95 993 C2-sport - sold
'06 M3 Vert - sold
'10 TDi Jetta Cup Edition - totalled
'02 996 Cab - sold
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