Forum Readers:
Thought I would share with you all my latest experience with the '06 ML350. M272 w/ 158K miles.
Symptom: - Sudden and harsh misfiring, CEL flash and engine shut off.
Warning: - NONE - no previous drivability issues, no chronic CELs
Initial Findings:
- Plugs Good
- Coil Packs Good
- SDS indicated multiple misfires
- Compression test - All good except for #5 Cyl - read "0" compression
- Borescope on #5 showed 1 intake slightly open/misaligned compared to other
- Removal of Valve cover showed rocker misaligned off cam lobe
- The Scope also showed the Piston and cyl wall to be damage-free
Further inspection found the dislocated rocker seriously scored and damaged the cam, valve guide and top of valve. This required the removal of the left cyl head to R&R the valve. On top, a new left intake cam, spring, rocker, guide, etc...and all the trimmings.
PLUS - in the breakdown, requiring the removal of the intake manifold, it was found that the left side tumble flap actuator was broken on the exterior of the manifold, possibly indicating that the internals of the tumbler malfunctioned, causing a piece of the flap to be sucked into the #5 cyl, momentarily disrupting the valve.
After inspecting the internals of the old manifold, indeed that was the case. The left side tumble flap had broken into 2 pieces, flopping freely inside the manifold. Compared to the right side flap, which remains uniform in its structure and motion, something in the left side flap had disintegrated, supporting the notion that a piece could have been sucked into the #5cyl intake port. In fact, the point at which the flap was most loose was directly above the #5 cyl.
Here are a new photos for your entertainment.
Plastic in an Engine? Good idea? Bad Idea? Did it save me from a total disaster or cause this extremely expensive situation?
I can only say good things about the team at RBM of Atlanta for the way they helped me and kept me in the loop. Forum-folk are not usually the typical client. They entertained every question, walked me through each step and treated me fairly on parts prices and labor rates.... Let's hope the tech followed his MOPs and the torque wrench was dead-on
Thanks for reading!!!
Jeff