fstshrk

I bought the car (95 C36 amg) after a 20 mile test drive. No noise.

I come home (about 80 miles) away, and now there is a marbles type noise coming from the front of the engine bay.

Any ideas?

I think it is either the power steering pump or the water pump pulley, but there is no water leaks.

Oh well, at least I got a great deal on the car.

svt ricco

if it sounds like a diesel engine, i think its normal. correct me if i'm wrong

fstshrk

It does have a diesel like sound. But does it get louder as the car gets hotter. Today is a 100 degree day here in SF Bay Area and I made three stops on the way from picking up the car. One to fill up with gas and one to pick up some groceries. I did not notice the noise until I pulled to my driveway. There is no fluid leaks, the belt seems nice (and not overtight) and the car runs and drives beautifully (I LOVE IT). It was driven only 7K miles in the last 4 years of ownership so I knew I needed to do some R&R, but not on the first day of ownership

How loud is the diesel sound normally? I can barely hear it inside the cabin, but I can totally here it when I open the hood and listen to it.

SeeKlasse

i think the deisel sound basically comes from the longer amounts of time between piston firings. all the 350sd crank they used on the m104 does is increase the stroke, which increases its travel time up and down, and thus a bit more time between firing so you get that really trucky sound...

fstshrk

Hi SeeKlasse,

Understood. I will get the car checked out anyhow. It would be bad to drive the car around if this sound that I am hearing is not the normal diesel sound

I was wondering if there are any opinions on where to start to figure out the source of the sound.

AMGC

the diesel sound is perfectly normal dont waste your money

StapleGun

Sounds like a belt tensioner gone bad...like a metal 'maraca' going off. Belt may well maintain tension but is about to go, replaced on ML320 and the sound you're describing is spot on.

fstshrk

Thanks, I think that is what it is too.

Now that the car has cooled down, I am going to take a peek later today.

vinceC

[QUOTE]i think the deisel sound basically comes from the longer amounts of time between piston firings. all the 350sd crank they used on the m104 does is increase the stroke, which increases its travel time up and down, and thus a bit more time between firing so you get that really trucky sound.../QUOTE]

Sometimes people trying to help say the wrong things.

First error:

M104 C36 crankshaft PN = 104 030 10 01

OM603A 350SD crankshaft PN = 603 030 25 01

The M104 C36 engine indeed has a stroker crank, but it was designed specifically for the C36. The 350SD crankshaft is for diesel service, has much larger bearings, can't be run at the high RPM of the M104, etc.

Now for the second error.

A longer stroke does not change the timing between firings (power strokes), which remains at 120 degrees of crankshaft rotation no matter the stroke. It does increase piston speed, but reduces piston acceleration.

The only thing that might cause noise that is related to the rotating mass in high performance engines like the M104 in the C36 might be piston slap, which is almost always when cold.

SeeKlasse

i was actually wondering about that. concluded that either the stroke time is longer or the pistons move faster to cover the greater distance....

thanks

fstshrk

Update on this.

Car has a bad serpentine belt tensioner. Getting replaced tomorrow.

svt ricco

please let us know the cost of the repairs. thanks!

StapleGun

Hmmm, did I mention this before?

ohlord

all the talk about diesel sounds from an m104?
http://www.autohausaz.com/search/pro...0Pulley/Roller
install a new belt while you are at it.
And since you did not have a pro ppi before you bought it get the wire harness inspected now,before it strands you.
ohlord

fstshrk

Car had already the wiring harness, control arms, and head gasket replaced not more than 10K miles ago.


Thanks

fstshrk

Yes

fstshrk

Picked up the car from the mechanic today. The belt tensioner pulley bearing was going bad, it ended up moving forward and the tensioner pulley was rubbing on the tensioner itself.

About $500 later, the car is back to sounding normal again. The parts were 160.00 total. 3 hours of labor (which was probably too much, I was expecting more like 2).

SeeKlasse

man thats great you had the head gasket + harness done recently. i had to do that job on both of my c280's, costly but relieving all at once. mb released an upgraded gasket after they found out how weak the oem ones were. the only ones you can buy now are the upgraded ones. they should last almost 200k miles instead of a meager 100-120k....

vinceC

Just curious - does it still have a "diesel" sound?

fstshrk

Actually, yes, it does

It sounds a bit like the modern turbodiesels while idling. Very low, but distinct idle sound.

svt ricco

you can never get rid of the diesel sound-fyi

vinceC

Hmmm. The only sound I can think of would be the injectors. I suppose those not familiar with the M104 engines might describe the sound like a diesel. The plastic cover over the injectors does amplify their sound a bit. To me they sound like a bank of relays clicking. I guess I'm used to real diesel noise - like a 240D rattling like a bucket of rocks in a paint shaker.

fstshrk

Exactly. This is why I thought it sounded like a modern turbo diesel like the E320CDI.

I had a Duramax 2500HD diesel when I used to race and used it for towing and it does not sound like the Duramax at all.

EVLC36

That wont be it, as the 3.6 M104 is the only model that has the diesel noise, my old C280 was smooth and quiet, my (now sold) C36 and all others I have heard have had the diesel noise.

EVLC36

[quote=vinceC;2831442]While not being the exact same part, the C36 crank WAS based on the 350SD crank.