Volvo V40 shaking at 60-70mph
May 21, 2009 2:10 AM   Subscribe

I own a 2001 Volvo V40 that done 109000 miles. It has developed a fault that I am having difficulty identifying. When reaching speeds of 60mph to 70 mph the car is shaking badly when the engine is under power, it stops when you ease back the accelerator even if maintaining the same speed. Up to 50/55mph it is not evident. I have had all wheels rebalanced and new tyres on the front, the rear are also in good condition. Swapping them round made no difference. Can anybody point me in the right direction?
posted by oxide to Travel & Transportation (13 answers total) 1 user marked this as a favorite
Is there perhaps a balance shaft belt doing something weird at those speeds? Or bad motor mounts that happen to not be holding things in place when it hits a certain frequency? (This seems less likely since the issue isn't speed-dependent, but under-power-dependent, but it might be torquing them strangely.)
posted by disillusioned at 2:15 AM on May 21, 2009 [1 favorite]

Sounds like an engine balance issue. Can you reproduce this problem when parked/neutral and running the engine at the same RPM as highway speed?
posted by zippy at 3:15 AM on May 21, 2009

I would also check out your engine mounts.
posted by dunkadunc at 3:16 AM on May 21, 2009 [1 favorite]

I had that on my '70 Impala at 64 MPH. Turns out the u-joint bearing cap had slipped a little in its seat. Look at the half-shafts (axles); there are often little balancing donuts on them that come loose.
posted by notsnot at 4:05 AM on May 21, 2009

In a front wheeled car, it's probably the axles.
posted by gjc at 5:42 AM on May 21, 2009

I second the engine mount.
posted by Gungho at 6:23 AM on May 21, 2009

harmonic balancers can "slip". also check motor mounts & driveshafts/ujoints.
posted by patnok at 6:50 AM on May 21, 2009

It'll bet it axles.
-A wheel balance issue will telegraph distinctly through the steering wheel if a front wheel is out of balance.
-If your vehicle is all wheel drive and you suspect a bad drive shaft, that will typically be constant and progressively worse based on vehicle speed.
-Bad motor mounts will be most evident upon acceleration from a stop or during transition from drive to reverse.
-A CV axle, if there's excessive play in the CV joint, will cause a whole-vehicle vibration or shudder when transitioning from highway cruise (when they're less loaded) to acceleration at highway speed under load.

To check:
Just lay on the ground by the front wheel of your vehicle in a position that you can see the axle (it will have a rubber boot on each end and connect the center of the front wheel hub to the transmission, if you don't know). Grab the center section of the axle-shaft and shake in every direction. If you feel any appreciable play or hear a clatter, you've got a bad axle. Check both sides. Also, if your CV boots are torn and leaking, I wouldn't even bother giving them a shake test. New axles for your Volvo (aftermarket brand) will cost less than a hundred bucks each. The labor will probably run about 1.5h to 3h per side.

I diagnosed an identical situation yesterday.
posted by Jon-o at 7:07 AM on May 21, 2009

Classic inner CV joint symptoms.

Often hard to tell which one it is without taking them off, may as well change them once they're on the bench.
posted by KenManiac at 8:13 AM on May 21, 2009

I third the engine mount.
posted by The World Famous at 10:16 AM on May 21, 2009

Google "55mph shimmy", its a very common issue.

Could be rims with hub rings.
Not properly balanced tires
Control arm/thrust arm
Tie rods.

Pretty much get your front end suspension checked out thoroughly.
posted by wongcorgi at 10:28 AM on May 21, 2009

I had very similar symptoms - shaking in the steering wheel only between 70 and 80 km/h. They replaced the tie rod ends and it stoped completely.
posted by trialex at 3:31 PM on May 21, 2009

So, I just got done replacing the axles on the vehicle that I described in the earlier post. Before: severe shaking through entire vehicle under acceleration at speeds above 55mph. No steering wheel shimmy, or directional pull.
After: I replaced both axles. The old axles had excessive play in the inner CV joint. Test drove and shaking is completely eliminated.
posted by Jon-o at 8:39 AM on May 26, 2009

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