This morning when starting my '01 C240 I noticed a noise coming from the belt system. It sounded like bearing noise, but I was not sure which pulley was the one to blame. Heard about idle pulley being the cause, but what about others? Like water pump etc. The car has 77,000 miles, so anything is possible. Anybody experienced something similar? Where should I start?

Thanks.

Take a spray lube can -WD40 -LPS 2 -Tri-flow -with a nozzle tip spray it behind the back of the water pump pulley . My Benz has a cone pulley so it hard to spray down and forward ( it might take two applications ). The squeak will go away , if the pump is bad.

Some idler pulleys can sequel steady , water pumps may stop & start making noise.

You can always slip the belt off the tensioner and turn each accessory pulley by hand to find the offender.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Thanks,

I will try that.

An update: The water pump seems OK (also no leak) but the idler pulley wobbles slightly, maybe .5 to 1 mm, not sure if this could cause the noise, but will replace (only $20 or so, as opposed to $100+ for water pump) and see. Hopefully it is the cause.

Thanks.

guys you've got to be kidding, sprAYING WD 40 on the bearing ? No way even an antique mechanic will tell you the same thing, no such technique or proceedure, if its the bearing, you need to replace it, all bearing in that area are sealed type. Men from which planet are you guys from?

and for the water pump, its also sealed type and unless htere is no water, it will indeed make a squele sound to check if the water pump is ok, first, leak test, then check if water is still circulating if so there is nothing wrong with the water pump, usually the idler bearing goes out first, if thats the case you need to take it down and have a machine shop press out the bearing and replace another new one which will also require a machine to press it back in, doing it manually is possible, but warning unless you have a digital hand that can precisely press in the bearing with a nice alignment, its best you let the machine shop do it.

message intended for schraube only.

<>

France ...

....for any Early SNL crew amongst us.

Nobody was suggesting that WD40 was a fix for the problem, only a diagnostic tool. If a bearing is squealing due to lost lubrication, WD40 will temporarily silence the squeal and allow you to find the problem.

A less militant approach to replying to threads will serve you well on this forum.

I've never had luck with WD40 finding a waterpump bearing squeal - usually those bearings, which are usually shrouded by the pulley, only squeal as a result of the pump seals having failed and allowing water into the bearing. Most cases, the leaking antifreeze will be found before the bearing starts to squeal.

Agreed with others that removing the belt and spinning the pulleys is the best diagnostic method - but have you ever tried to remove the belt on a W140 3.2L engine???

Shall we now go and consume massive quantities of chicken embryo's?

Message intended for Cool only.

I have had more than one water pump stop squealing ,with the lube spray technique . Most newer Benz pump aren't rebuildable ,these squealing pumps had good bearings and had seal issues .

As I wrote its difficult to spray behind the pulley with the nozzle. If your nozzle no longer sprays straight , seek medical help.

Oh ,, I am from earth ,last time I looked.

Have you checked the A/C compressor pulley?

__________________
2005 Pathfinder LE
2001 E55
1998 M3
1982 320i