2001 740i Sport Timing Chain Guide Questions

[risktkr]

I didnt rebuild the VANOS units. Shop said no need to. They did replace the solenoids.
I dont always get any noise. Usually if I do not drive the car for a week or so.

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Must I remove the timing covers to check these valves? As for 20/50, I thought I read somewhere that the VANOS units need thinner oil, 5/30 to work correctly? Thanks in advance for your reply. Mike

[740ilDuke]

User preference. I've been through it 3x over the years. I asked my parts guy how many chains he'd sold over a decade, and it was just a handful. Not enough to make me want to replace the chain. When failure occurs it's due to the guides typically, not the chain.

[oldroller]

Mike, the solenoid check valves live just beneath the solenoids in the head. Unbolt the seal unit, remove the solenoid, and insert a bolt (6mm, 8mm? can't remember)
into the check valve and pull it out. Has an O-ring seal. Check the bolt size on the replacement for removal.
Simply push it in to seat, reassemble.
Never heard of any problems with thicker viscosity oil on the Vanos operation, my M62 has hummed over 10K since the rebuild with the heavier oil, no issues.
I do live in a temperate zone though, rarely falls below freezing.

[kouks]

I personally would not use 20/50 oil in freezing temps, too much pressure in the engine when the oil is cold. Stay with a 5/30 or 0/40 oil in the winter, then switch to 20/50 in the summer months. Personally, I'd use LUCAS Oil Modifier with 0/40 all year long. I do that in Cali and I do live in an area where winter temps do go to below freezing, it works just fine and no engine vibrations while the oil is getting warm. The Lucas stuff does a great job of creating a good oil coat on the metal. I took the driver side head off the engine a couple weeks ago, and even sitting in the driveway with no oil circulation for over a week, the metal was slick. I've also read that the combination of Lucas with a 10/40 oil adds the equivalent of about .001 inches of surface to the bearings, protecting them from wear. This was on the track forum with all those guys trying to destroy their cars at high rpms.