Engine Vibration - Would a new snub mount help?

[jdp1962]

My engine has a strange characteristic. It's a 2.4 V6, FWD with multitronic auto. For almost the entire rev range, it's every bit as smooth as you'd expect it to, but at 1800rpm, there's a noticeable tremor. As soon as the rev counter goes past 1800, it smooths out again.

I don't think it's gearbox related, because if I rev it to 1800rpm in neutral, it still does it. I've no idea what is causing it, and nor has my local dealer or indie (I asked both). One of them said it might be the dual mass flywheel, and the other said it didn't have one!

After reading some threads on here, I was wondering whether fitting one of these might help.


Ideas, anyone?

 

[jdp1962]

Bump

 

[Turkster]

does your car have a duel mass flywheel ?

 

[jdp1962]

does your car have a duel mass flywheel ?

Er, did you actually read the post? I don't know. One garage tells me it has, another tells me it hasn't.

 

[jdp1962]

Update. I've just come off the phone from speaking to Awesome GTI about the problem, and the possibility of solving it with an APR snub mount. They reckoned it would have nothing to do with the engine mount, but suggested the possibility that the tremor at 1800 rpm is a stutter caused by a changeover of a flap in the inlet manifold. He wasn't sure, but said that although he had no great knowledge of the 2.4 V6 engine, this was a common problem on the 3.2 VR6 engine.

So I have a new possibility to explore, but no real idea of how to go about exploring it. Does anyone know what this flap thing is, and whether it can be fixed?


(Oh, and apologies to Turkster for the rant. I had just spent 8 hours on the road when i read that.)

 

[wand106]

Update. I've just come off the phone from speaking to Awesome GTI about the problem, and the possibility of solving it with an APR snub mount. They reckoned it would have nothing to do with the engine mount, but suggested the possibility that the tremor at 1800 rpm is a stutter caused by a changeover of a flap in the inlet manifold.

Hi Did you ever get to the bottom of this? I have the V6 2.4 engine in a 2004 A4 (42k on the clock) I just bought. It is manual though, but suffers exactly the same vibration as you describe, you can rev it in neutral and it is around the 1800-1900 mark, you get the vibration. The garage reckon flywheel, and they want to replace the clutch as well, quoted around £1k at least, and thats with no garantee of a fix, just wondering if you got it sorted and if so what it was.

Any advice / info welcome at least I know I'm heading in the right direction.

Wayne

 

[jdp1962]

Hi Did you ever get to the bottom of this? I have the V6 2.4 engine in a 2004 A4 (42k on the clock) I just bought. It is manual though, but suffers exactly the same vibration as you describe, you can rev it in neutral and it is around the 1800-1900 mark, you get the vibration. The garage reckon flywheel, and they want to replace the clutch as well, quoted around £1k at least, and thats with no garantee of a fix, just wondering if you got it sorted and if so what it was.

Any advice / info welcome at least I know I'm heading in the right direction.

Wayne

Sorry I never got round to replying sooner, but just today, I think I might have found the answer. And if I have, boy is it a strange one!

Driving home today, I noticed that the stutter at 1800 rpm was barely there. Not daring to believe it could just have vanished after four years, I began experimenting by taking the revs below 1800, increasing them gently, dropping back, and repeating the exercise. Sure enought, the stutter was all but gone.

Racking my brain to think what might be the reason, the only thing I could come up with is that on Sunday, for the first time since I bought the car, I put standard 95RON Shell unleaded in instead of Optimax/V-Power. The tank was only half empty, so by filling it, I have created a 50/50 mix of standard and V-Power, but it is the only thing that is different.

I will monitor the enigne over the next few days, and run the tank down to near empty, then fill it up with 95RON unleaded, see what happens.

Weird, huh?!