speed43

If you have ANY idea what could be the noise please let me know, the clip is about 7 MB, download it and let me know what you think this noise is, thanks.

Note, the noise goes away when the idle hits exactly 2000 rpm. From there up its smooth.... Below 2000 rpm the noise comes back.

CLIP:
https://www.dropbox.com/s/0encfwu2z4t0g5n/A1.wav?dl=0


BEFORE THIS NOISE STARTED

I had a oil leak on my intake manifold.
Took it off, fixed leak with new gasket.
Installed and let set for a day.

I than turned the car on, and a clattering/ticking noise started to come from what seems the top of the engine.
I checked to make sure everything was connected right and still heard the noise.

I know I didn't drop anything in the heads as I used rags to cover the holes up.
But I went ahead and took off the intake and checked the valves and all of them where fine. I than installed ANOTHER intake manifold I had nice and ready for future use. Started the car and the noise still there.

Maybe some silicone or debris fell in somewhere and clogged a lifter?
Does it sound like a lifter to you?

Also, by mistake I cleaned the Mass air flow sensor with throttle cleaner. Could this have anything to do with that noise?

speed43

Come on guys one of you must have some ideas.

Sulaco

sounds like it's having rough idle issues too?

need more info, not from sound inside car. where on the engine is this sound heard the loudest? front? one side of the engine in particular? recording a video of you moving the camera around the engine bay looking at the engine from different angles would be far more informative.

could be a pulley bearing (my water pump bearing started to go and made this AWFUL sound of heavy metal hitting heavy metal that convinced me my engine was failing), could be lifter tick, sticky valve. more likely a pulley on the front, as lifters and valves doing things like that are not as common.

does it go away once the engine is warmed up to 80C?

cm60k

^^Agreeeeeed^^

Honestly; can't tell for sure from this clip, but as i think, it could be intake air leaking.!

is there any problem with idling: lose power/RPM playing/surge acc./throttle response in all positions..?!!?

ZAYED,,

speed43

Thank you for your comments!

The noise is from top back side.
I just got a check engine light.
Codes that came up are:
P0208, injector circuit open cylinder 8.
P0110, intake air tem sensor circuit 1.

I checked connection on injectors all good. Took off spark plugs on cyl 8 all good. When plugs were out i started car nothing came out......

I will star the car to get it to 80 degrees as suggested and see if noise goes away. Will try video too.

Sulaco

I think Zayed is correct, judging by your check engine codes!

luckily it doesn't sound like a costly, serious problem. something isn't quite right after your recent repair.

Pagz

Speed43,

Did you open up the intake manifold?..

speed43

Yes, i had a leak on the bottom and top part. I made a good seal, no leaks.

Update, i went ahead and let the engine run, after a few minutes the noise stopped! I would not have let the car run that long since i had no clue if it would hurt the engine. But i did as was suggested and sound is gone. Have no clue what caused that noise but I'm glad it's gone.

Thanks everyone!

Sulaco

Not so fast, there. Just because the sound went away doesn't mean the problem solved. Once the engine is cold again, if it continues to make the sound and throw CEL codes, you have an issue.

cm60k

+1,

Try to spray with Electronic cleaner in all area of intake manifold while the car running for about 10 minutes, then diagnose the car, delete all codes,,

start the car again for 2 minutes, then switch it-off, when any code comes again, means should to solve it, even if it deleted from ECU memory...

ZAYED,,

Pagz

Agreed zayed.. check for vaccum leaks, these manifolds are incredibly hard to reseal, hence they are deemed unserviceable by mb.

Could variable length butterflies cause tapping with poor vaccum supply or if the vaccum camber in the lower half has a leak?.

speed43

I reset the codes, i will spray the manifold with carb cleaner and see what happens. I did let the car get cold (im in Chicago) and went to start it. The noise came back very soft and for a few seconds, than the noise went away. Not near what it was before.

I inspected the car too and found a part that had no vacuum hose hooked up to it at the bottom. Ive never noticed this before tikl today.

Can you guys look at the pic below and tell me what hose goes there? Its the little tube next to the electric connector, when installed the tube and connector face down.

https://www.dropbox.com/s/mdxcc0anth...39634.jpg?dl=0

speed43

Uploaded the picture.

cm60k

Bottom port should to be closed,,

there are two ports at the top, one goes to the intake manifold & one goes to the Y connector, which connects to the shut-off valves, see diagram..



ZAYED,,

speed43

Thank you zayed! I had the top hoses crossed, which may or not make a difference .
But, when you say the bottom port should be closed, you mean there should be a cap so no air comes in? On mine theres no cap and if i suck or blow though the top right port air goes right through the bottom port. Should i seal the bottom port? Are you sure its suppose to be closed? If yes, why even make a port at the bottom?

cm60k

AnyTime,

Many MB models using same this change-over valve, it helps to re-circulate air,,

they use the bottom port for extra solenoid, especially in diesel Engines..

ZAYED,,