E300TD drone 1500rpm

[horatio]

Sorry for yet another question!

My E300 makes a drone at about 1300 to just under 1500 revs, from the engine (definitely not drivetrain, it does this while parked). Otherwise it drives very nicely, no smoke at all and very smooth.

My initial thought is the exhaust manifold gaskets - there is soot around one of the head connections and also light soot where the manifold connects to the turbo. But why would the drone only be at such a specific rpm?

Could it be a turbo fault? I would have thought a turbo problem would cause a whine or smoke.

Has anyone here experienced something similar? This really ruins the drive and is getting on my nerves!

Thanks

 

[horatio]

I have tried to pinpoint from the engine bay but these things make such a naffing racket it's no use!

 

[Tim203]

Sounds exhaust system related at that rpm. What's the general condition and are there any broken rubber mounts ?

 

[Erfan]

Have you checked the gear selector bushing? It cured a rattle for me and cost pennies.

 

[horatio]

Sounds exhaust system related at that rpm. What's the general condition and are there any broken rubber mounts ?

the drone is definitely from the engine area. I have bought a new manifold gasket so I will change it and hope for the best.

I hate this job but seem jinxed to do it on every car I buy. At least there is bags of space to worth in.

 

[horatio]

Well I changed the exhaust manifold gasket but it still makes the drone. You can feel the slight roughness. It only starts to do this when the car is warmed up. I've checked everywhere but can't find an exhaust leak.

Could it be something to do with the turbo?

I know the engine mounts need changing but can't see why they would affect this problem.

Any thoughts? Thanks

 

[BlackC55]

I would put money on the mounts being the cause.

 

[carat 3.6]

At the front of the engine is a small shock absorber for the belt tensioner, with the engine running gently put pressure on it with a screwdriver and see if the drone noise stops.

 

[horatio]

Thanks, will change the mounts and see what happens. I can see that the left one has collapsed.

The belt damper has already been done!

Cheers all

 

[horatio]

Well I've changed the mounts. Car is much nicer in general but the drone is still there and probably getting a bit worse.

It's a drone/groan between about 1200 to 1500 revs, you can feel a very slight vibration when it does it. Will do it stationary and on the move, and when the revs drop back through the range.

Could it be the injectors? One is a bit ticky.

 

[John Jones Jr]

My initial thought was belts, tensioner, idler pulleys or all three just like Carat 3.6 suggested. I'd remove belts and start her up, worth a shot.

 

[themorg]

hiya pal ,
this might sound a bit mad but ,put your car on car ramp and check the alternator for vibration with a screw driver to your ear,i had the same problem with a e320 cdi ,an internal bearing had gone ,changed the alty and all is fine now ,hope this helps

 

[horatio]

I've had a think about this and I reckon it might be EGR related. Reason being - the EGR opens when temps increase and will start working at certain revs?

Drone is probably the wrong way to describe it, it basically runs a slightly rough around 1500rpm. It's irritating around town because you're always in that range. It doesn't seem to do it until the car has warmed up.

Deleting the EGR looks a pain in the backside because it will need faffing about with the electrics to fool the MAF so hopefully I'm on the right track...