Horrible noise
 

Coming from the front of the engine compartment in my E320 Station Wagon.

Tried to stethescope it but I can't tell.

It sounds really loud when the engine is being shut off and at times when accelerated.

Sound like a bucket of bolts is loose inside a rotating drum.

Otherwise car runs good, a/c works and power steering is ok.

Any thoughts?

thanks.

Any fluids leaking?

Fan hitting the shroud, maybe?

Smog pump ate itself? Idler pulley bearing? Power steering pump? Valves due to oil tubes cracked and not getting valves enough oil?

The reason I'm asking about fan hitting shroud is that the noise only happens on engine shut-down and occasionally on acceleration, which could mean it's a bad motor mount that's allowing the engine to move beyond it's allowable limits and thereby causing the engine-driven fan to impact the shroud.

The other proposed causes (smog pump, pulley bearings, etc.) would cause a constant noise, not just on shut-down and acceleration.

Just a theory.

Best Regards,
Rob

nestorb98, if the fan is hitting the shroud you will see rub marks on both the fan blade tips and the shroud. If that's the case realign the shroud slightly to eliminate the rubbing until you replace the engine mounts, or if it's not possible to adjust the shroud position simply remove it temporarily.

What year? I'd take the belt off it and do a start, rev, shut down. If the noise is gone you know it's one of the belt-driven things. If it's still there it might be the tensioner or chain or slides depending on engine. Check the HB too, in the 210 cars there was a recall for them, probably not it but can't hurt to check.

Could be a cat gone bad also, the 96 and up cats have that darn brick that rusts and breaks loose and sounds like rocks in a can. My wife ML one side went then the other. Gotta pull a bunch of stuff off to get the exhaust out and replace as the entire piece is cheaper than installing 1 cat.

i'll vote for the engine fan hitting the shroud caused by broken motor mount or loose shroud.

Depending on the year it may not even have a mechanical fan. We're all just kind of guessing, which isn't much help to the OP, but then we didn't get much to start with.

Well guys...thanks for your inputs!

I took off the fan shroud and noise was still there.

Very loud and right by the A/C compressor...cycled the A/C and noise became louder when A/C went off.

Removed #7 fuse and noticed a change in the noise, so I think the compressor is kaput!

Car runs great so its me or an indy to the rescue...dealership is out of the question.

I have never done an A/C replacement on anything before...could this be done at home?

any thoughts?

thanks again

so the bearing in the front idler pulley of the compressor took a dive.only seen that once before.

How dificult is it for a do it yourselfer to repair this?

you need to remove the compressor and then have the right puller to get it off.the cost of new or rebuilt clutch assembly is not much less than a rebuilt compressor.

Actually, on some models you can unbolt the compressor and jockey it around in the engine bay and use the puller in place.

So, how about telling us WHICH model and engine of E320 you are working on?

If you do have to remove the compressor, that means you have to recover the refrigerant (PLEASE don't just vent it to the atmosphere), evacuate the system and then recharge it with the correct amount of oil and refrigant. If you use an indie shop to recover the refrigerant, they may give you a discount on the evacuation and recharging steps, which they'll have to do in any event. Since they get to resell/reuse your recovered refrigerant and know you'll come back for the rest, hence some give you a discount (I've known some that did it for free, which is nice).

And if you have to remove the compressor, then I'm with David: just buy a rebuilt compressor with the new clutch and bearing assembly already in place. The added cost of the recovery, evacuation and recharge makes the cost difference in parts less important.

Good luck.