4.8is N62 sounds like Diesel at idle under load

[nextelbuddy]

this has been happening for a few years now and i always thought it was knock sensors due to poor gas but new plugs, coil packs and years of good gas with octane booster and injector cleaner, the sound always remains.

it is literally this exact sound and exact same scenario in this youtube video i found.

if im in the drive thru or anywhere where im in Drive but have foot on the brake, the idle sounds like a diesel and is even worse with AC compressor on.

Looks like OP of this video marked it as UNLISTED which is why it wont play in the embedded player. including the URL to play on youtube


https://www.youtube.com/watch?v=j4LeTVbyquM



there's not too much on the subject in regards to solutions, just other people saying they have the same problem. i looked in forums for e60s and e70s as well but didn't come up with any solutions.

is it a valvetronic issue? is it something i can use INPA to recalibrate?

is this something that can be resolved with replacing both valvetronic motors with associated gaskets and seals?

besides the sound at idle when engine is warm, drivability is fine and no other odd noises or issues besides the terrible valve stem seal smoke i have going on which i hope to resolve in the next year with valve stem seal job.

im trying to avoid throwing parts at this issue as much as possible.

[X5chemist]

Is yours an '04?
Comments: "valvetronic. intermediate levers had manufacturing flaw in engines that were made in 2004"

Definitely valve train related based on other engines I've heard (non BMW engines). Use a mechanic stethoscope to listen at the valve cover.

[Homerlovesbeer]

Very odd and I hope you find out the cause. It would be nice if people updated posts/videos when they solve the issues.

[YETTI]

Mine has been doing the same thing, been trying to figure out this issue for months. Anyone have any update or was able to figure it out?

[PropellerHead]

Originally Posted by YETTI

Mine has been doing the same thing, been trying to figure out this issue for months. Anyone have any update or was able to figure it out?

If it's an '04, check eccentric shafts. There was a manufacturing problem and they were known to fail. I replaced mine six or seven years ago. They were $1400ea then.