Start with the simple one FIRST

400E w/102K mles
Typical Timing chain rattle...

Well after $1K the $13 valve "O" ring on the oil pump valve seat. I recorded the noise so there wasn't any doubt!

First visit - $750.00
parts replaced:
Timing chain
Upper rails
Chain tensioner

Second visit - $0.00
Re-check tensioner

Third visit - $250.00 (10 days later)
replace:
Oil pressure relief valve ($67)
Oil pump valve seat ($13)

Gee, he even tightned the oil pan gasket that was leaking for FREE! (and it still leaks)!

Oh Well guess it's good for another 100K miles
Anyone ever replace the lower oil pan gasket ($21) on a 4.2LV8?
Tks > BOBB