Originally developed and published here by unknown author: http://members.cox.net/rlacm/IntakeIndex.htm
Recovered and published by BMW-Planet.com – May 2012
BMW 540i (E39, pre-VANOS) Maintenance:
- Intake System Gaskets and seals
- Valley pan
Breathing new life into your M62's leaky intake system, and fixing that nagging
valley pan coolant leak.
At around 82k miles my engine was clearly showing signs of minor air leaks in the intake system: rough idle when cold,
occasional miss at idle, periodic extended cranking times during starting, etc. Additionally, a BMW tech pointed out that
my valley pan seal was leaking a small amount of coolant, a common occurence on these motors.
There is some good news here: these two problems, leaky intake seals/gaskets and seeping valley pan, appear to have
nothing in common except, perhaps, for mileage. However, even if you're only trying to fix one, it's an easy task to take
care of the other on a pre-emptive basis while you're in there. In the case of the intake manifold, the only additional work is
R&R of the water manifold/plumbing and the valley pan. Total additional cost is around $50, a little more if you replace
the two hoses that attach to the manifold. Conversely, if you're after the valley pan in the first place, the manifold
gaskets/seals come along "for free."
I reviewed the BMW TIS documents and decided this would be a fairly straightforward procedure: no special tools
required, and less than a day's work. So I headed over to the dealer with parts list in hand.