I have a 1998 E300 D with about 113,000. Recently the car started having what I describe as a roaring noise that occurs intermittently. It matches the RPMs and as quickly as it starts it goes away. I am thinking fan clutch. Does anyone else have any input?

Hard to say... These cars are generally so quiet that it's difficult to pinpoint a noise.

The only noises my car has made over the time I've owned it was some chassis vibration from bad engine mounts and also, at highway speed, I get a gentle "rummm, rummm, rummm" from the transmission area that sounds maybe like the driveshaft.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I would agree with that if the noise was constant... which it is not... and it will also make the noise when in park. But thanks for the input.

I know the noise you mean as my 1990 w124 300d non turbo (UK) car does it.

Mine sounds as if the auto box is whirring,but it is not though.The noise appears to come from the gearbox area but the car has not got the wind tray fitted any more so it is hard to be certain the area it does come from.

I reckon my tensioner pulley wheel bearings are bad but have yet to investigate properly,I can alter the noise which I suspect is bad bearings in the wheel by pressing on the tensioner quite hard at idle

Now I changed the leak off pipes at the weekend and while running the engine to check for leaks I came across a noise which was similar ,this noise could be heard at idle and slow driving.It was a tinny rattle and had been driving me mad.

The cause was the first 3 injector pipes from the front of the engine.

There is a bracket they clip to and they are held in plastic clamps,well sometime the injector lines have been off the engine and the lines had been replaced with the clamp already in the bracket so they sat on top of the clamp they were supposed to be held in,just slightly above the plastic but close enough to rattle and vibrate on it.

I had my hand on them with engine running and felt vibrate,so I placed my fingers on all 3 and the noise went,so unable to remove the plastic clamp I just used two cable ties for now to hold them down to it.

I was very shocked at how delicate the injector lines are compared to other diesels I have owned and I suppose the thickness of them lends itself to picking up vibrations.
Anyway they were extremely noisy and would get louder as engine revved until at around 2k revs the engine noise drowned them out.

Fan clutch locking up or Aux fans engaging. Should be easy to determine if either is the cause if you can pop the hood while its in its intermittent mode.

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

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

Those too, are what I would suspect.

Mine's as quiet as a mouse as contrasted with my '83 300SD - even when my '99 E300TD's auxiliary fans start and run = it's just a very quiet car.

All in all I'm quite pleased with mine.

my 99 was running on the hot side, and the fan cluch was replaced.
the new clutch is a little stiff, and seems to have some fan roar when first accellerating.

a locked up fan clutch will absolutly roar. had one of those on my old merkur scorpio.

you can test the clutch... lift the hood, spin the fan, it should offer some resistance, and stop spinning within one or two spins. if it is grainular feeling, or worse (locked up), then replace it. if it spins freely... you will need one in hot climates. you might get away without it in the cool. I"m in PA, mine spun freely, was quiet as a mouse, but that temp guage just kept going (way) above 1/2 way, and a fresh (but stiff) clutch was the solution.

Thanks for all the input guys... new fan clutch is on the way.. I suspected it was that.. as I had a similar problem on a SDL and Isuzu Trooper.

Hey KarTek...that "rumm rummm rumm" sound is familiar. Same thing on the highway in my '99. Haven't gotten around to figuring out what it is yet. Another opportunity for improvement...

rsj6667,

Were you able to take care of the roaring issue? My '98, with 139k, has gotten loud over the last three days. It seems to come on when I'm accelerating, but even while cruising the car seems to be much louder. Just curious as I believe I need to head off a potential problem. Car is running at normal temps.