m103 143amp alternator noise - PeachParts Mercedes-Benz Forum

JamesDean · #1 01-19-2010, 12:03 PM

Hello everyone,

I know some of you out there have fitted a 143amp alternator from the w140s to your m103's.

I've done the same with my 3L m103 in my 190E however at idle, it makes this chirping noise.

This is my third alternator from Advance, its under warranty and what not. I just don't understand why its chirping.

Power output is good, 14.v2v at idle, no complaints.

If anyone has any ideas or thoughts?

I can make a recording later on when I get home.

Thanks,

Kris

pawoSD · #2 01-19-2010, 06:59 PM

Are you sure the belt tension is correct? A 143A alternator under load can put a LOT of friction on the belt.

If the belt tensioner or shock are weak/failing it will likely cause chirping.

pelon · #3 01-19-2010, 07:15 PM

Maybe you should put a bigger one on.... 250amp???

layback40 · #4 01-19-2010, 07:17 PM

Kris,
Are you sure you dont have a birds nest in it? LOL

You could try a little bees wax or candle wax on the belt. It may shut it up.

If its the belt, turning on your lights etc should make it worse, a good way to confirm belt problems.

JamesDean · #5 01-19-2010, 07:18 PM

Quote:

Originally Posted by pawoSD

Are you sure the belt tension is correct? A 143A alternator under load can put a LOT of friction on the belt.

If the belt tensioner or shock are weak/failing it will likely cause chirping.

I hadn't thought of this. How does one go about checking to see if it has proper tension? I recall vaguely about some sort of marking on the belt tensioner device..

oldiesel · #6 01-19-2010, 07:27 PM

spray some water on the ribbed side of the belt with the engine running,if the belt is the cause of the chirp it will stop chirping for a couple of minutes without contaminating the belt with something that will cause it to slip. Don

pawoSD · #7 01-19-2010, 09:36 PM

Quote:

Originally Posted by JamesDean

I hadn't thought of this. How does one go about checking to see if it has proper tension? I recall vaguely about some sort of marking on the belt tensioner device..

I know that MB tech's use a tool that they pull on the belt with, it has a scale on it or something, gives a measurement of the proper tension. My M103 has a tensioner with no tick mark on it, it is completely void of any marks....so I when I put on a new belt, I just guessed at the tension.

I must have been right, because it has been about 10,000 miles since then without any issues.

Try pushing on the belt in an place where there is some distance between pulleys, if it gives easily, then there is probably not enough tension. It is pretty firm on mine.

JamesDean · #8 01-20-2010, 01:08 PM

well..the water trick worked. noise went away after i sprayed a little on the ribbed side.

however, i went to tighten the belt, and i felt it prior to doing so and there is a good amount of slack. I can pull the belt up and touch the plastic cover over the distributor.

I tried tightening via the adjust screw and ccw loosened the screw and had no change in belt. cw tighented the screw but had no effect on the belt.

Does this mean my tensioner is toast?

MTUpower · #9 01-20-2010, 01:17 PM

Is the m103 a diesel? Isn't this the diesel discussion? Go back to the gasser side!

JamesDean · #10 01-20-2010, 01:19 PM

hey! i just noticed that I started this thread in the wrong side. hahah smooth.

Its ok though.. I have 2 diesels!

MTUpower · #11 01-20-2010, 01:21 PM

Quote:

Originally Posted by JamesDean

hey! i just noticed that I started this thread in the wrong side. hahah smooth.

Its ok though.. I have 2 diesels!

We'd be glad to solve their problems, otherwise you have to have do 50 pushups in 50 seconds.

JamesDean · #12 01-20-2010, 02:00 PM

lol, if any moderators happen to spot this thread, could you kindly move it to the tech discussion forum. Much appreciated!