Fig. 151: Identifying AGM Battery
Introduction
In September 2002 so-called VRLA batteries, better known as AGM batteries ,
were introduced.
(VRLA stands for Valve Regulated Lead Acid, i.e. lead acid battery with pressure
relief valve; AGM stands for
A bsorbent G lass M at, i.e. absorbent glass f
The valvetrain on the N52 introduced in 2006, used 5 mm valve stems on both
the intake and exhaust. To
increase durability, the exhaust valve stems were increased to 6 mm from 6/06
production.
All of the new NG6 engine have adopted the 6 mm valve stem for the exhaust, the
intake stem remains at