Engine: D5: S60 D5 Rumble at 1600-1800rpm hard acceleration

[SteveP]

Hi all,

I've recently purchased an S60 D5 last month, on the whole I'm very impressed with the way it drives, the economy and the comfort.

However, it has this week developed a slightly weird issue which I can't seem to fathom. Under hard acceleration between 1600rpm and approximately 1800rpm there is a slight rumble. The rumble appears to come from the passenger side of the car and it seems worse when accelerating hard when turning right. I can't replicate it when turning hard left and accelerating just as hard. However, with cheap front tyres and wet weather mean testing this theory is a little tricky(!) but I believe this to be the case!

So my initial thoughts in order of likelyhood, please correct me if I'm a million miles away but I'm not all that familiar with these cars yet!

1. Top Engine mount, I believe this is mounted like a petrol car on the passenger side bulkhead?
2. Rear passenger side bottom engine mounts (I believe there's two of these?)
3. CV joint? But there's no clicking/popping and it can't be replicated off the power
4. Wheel bearing? But there's no noise when moving at a constant speed, and again doesn't occur off the power

The car is otherwise in seemingly great health and wasn't doing this until this week, it has received a new flywheel, clutch and clutch slave cylinder 6 months ago.

[reesky]

Originally Posted by SteveP

Hi all,

I've recently purchased an S60 D5 last month, on the whole I'm very impressed with the way it drives, the economy and the comfort.

However, it has this week developed a slightly weird issue which I can't seem to fathom. Under hard acceleration between 1600rpm and approximately 1800rpm there is a slight rumble. The rumble appears to come from the passenger side of the car and it seems worse when accelerating hard when turning right. I can't replicate it when turning hard left and accelerating just as hard. However, with cheap front tyres and wet weather mean testing this theory is a little tricky(!) but I believe this to be the case!

So my initial thoughts in order of likelyhood, please correct me if I'm a million miles away but I'm not all that familiar with these cars yet!

1. Top Engine mount, I believe this is mounted like a petrol car on the passenger side bulkhead?
2. Rear passenger side bottom engine mounts (I believe there's two of these?)
3. CV joint? But there's no clicking/popping and it can't be replicated off the power
4. Wheel bearing? But there's no noise when moving at a constant speed, and again doesn't occur off the power

The car is otherwise in seemingly great health and wasn't doing this until this week, it has received a new flywheel, clutch and clutch slave cylinder 6 months ago.

I had a similiar problem when I bought mine. For me, it was the top engine mount combined with worn, out-of-round rear tyres.

Top engine mount is the cheapest to start with and easy to DIY

[SteveP]

Originally Posted by reesky

I had a similiar problem when I bought mine. For me, it was the top engine mount combined with worn, out-of-round rear tyres.

Top engine mount is the cheapest to start with and easy to DIY

This is reassuring as I had hoped if anything it will be the top mount, as it looks like an easy/cheap job!

[SteveP]

Ok well it's finally daylight and managed to get a look at it, the top engine mount looks relatively fresh and is of the square variety - I believe this is an improved design over the original?

However, the stabiliser bar can be moved and the engine mount moves within its cradle - is this supposed to happen? I'm guessing yes to an extent as it looks like it's more of a suppression kind of thing rather than doing any real support.

Is this normal for play?

http://www.youtube.com/watch?v=U9sB_-t-VxU

[Digidick]

Hi Steve

That amount of movement has been there since I'd owned her and the top engine mount is the new style and only around 8 months old. I never had a receipt in the paperwork because it was purchased from a Volvo part specialist on Ebay.

Cant think what the noise could be though without driving and hearing it.

[SteveP]

Hi Rich,

Thanks for the reply - thought that may be the case! Next port of call is the lower rod style gearbox mount on the passenger side. I'm just hoping it's not related to either clutch/flywheel as the fact they've been replaced was what attracted me to the car in the first place!

Cheers,
Steve

[Digidick]

Well if it does turn out to be clutch/flywheel etc its all under 12 months old and as you know I'm mates with the garage chain that fitted it so get in touch but its done a few thousand miles since fitting without any problems from day 1.

Does it make the noise as you release the clutch and moving off or just when you plant the throttle whilst already moving?.

[SteveP]

Thanks for that Rich. indeed - to be fair it's been fine with me with also up until last week.

It only makes the noise if you boot it from low RPM when you're already moving with the clutch engaged. As the revs rise to around 1600rpm it'll make the noise and then go away by 2000rpm. It's more pronounced when turning right and doesn't do it at all when cornering left and booting it from low RPM again, but does do it in a straight line.

If I get a chance tomorrow I'll drop the undertray and take a look at the torque rod style mount to see what condition that is in, as I'm hoping that's the culprit now. But I'm also wondering if it's related to the vacuum controlled engine mounts as I believe they are activated/deactivated around that RPM also.

[outnumbered]

The lower engine mounts are de activated at 1500 rpm no vac.could the DMF cause this
Mike

[5cilinder]

The mentioned rpm range correspond with harmonic 5 cilinder vibraton frequencies wich a good functioning dmf partly cancels
If the springs are broken/weak it cannot properly adsorp those harmonic vibrations
Also if its only pressent under high torque clues in to the dmf because if the springs cannot adsorp all the torque it behaves like a solid flywheel in the high torque ranges
And the specified rpm range is problematic due to harmonic self strength vibration frequencies

Check for noises idling and smooth gearchanging
The vacuummounts stiffen up at 1000rpm but those vibrations with non function mounts due to a vacuum leak are under 1000 rpm and a lot different in character