04-27-2016, 02:30 PM
|
 |
Member
|
|
Join Date: Jun 2014
Location: SA, TX
Posts: 6,474
|
|
Quote:
Originally Posted by Pierce330
Is valve stem seals only caused by oil weight or is it also caused by extended idling?
|
It's my understanding that the original VSS used by BMW used a rubber that broke down and caused oil to leak past into the combustion chamber which causes the smoke. Especially during extended periods of idling.
Switching to a heavier oil and using an oil treatment/conditioner just attempts to minimize the amount of oil slipping past the seals. That's the theory anyway, and has worked for some here.
__________________
2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)
2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)
2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)
|