i have read past entries to this forum re knocking noises in different parts of car and everyone seems to have a problem with noise when turning...well i have what seems to be the same problem but when driving straight and more often at low speeds. just seems to be a knocking noise from somewhere in suspension. it is not engine. sounds like a part of exhaust is loose or banging if you can imagine that ! :) i know that the rear suspension is weak as the car bottoms out if there is anyone in the rear. would a weak suspension be the only problem folks ?? and also..if im going to change rear suspension/shocks do i need to change springs too, and is it best to get original volvo springs. a friend told me it would be best !! anyone who can help here it would be very appreciated. this is driving me crazy ......

:hyper: I have the same problem, and when the car's serviced next month I'm gonna have volvo look at it. I'm not paying their prices though! I thing the springs become unseated and clunk or the top mounts rattle. Worrying, but not expensive. I'm replacing my suspension soon anyway so I hope that will remove the problem. Check your top mounts under the bonnet hinges, and behind the back seats. Keep an eye on them to see if they move (not while driving!) :o

Hope this all helps.

Knocking noises aren't the easiest thing to diagnose online & even Volvo dealers don't always get it right first or even second time.

However, hope these pointers help:

The 40 series is notorious for worn engine mounts causing knocking. Check them veeeeery carefully, especially the top mount. At first, the noise may only be evident when the car is being driven in gear. As mounts get worse, the noise can be reproduced just by revving the engine in neutral. The vibration causes the exhaust to rattle & eventually can cause exhaust failure.

Worn suspension bushes/links, worn/dry driveshaft ends also possible source of knocking noise.

Unless your 2001 car has been constantly used on rough roads, for towing or for carrying heavy loads, then I'd be surprised if the rear springs needed replacement yet, unless actually broken. You'd be amazed what difference a new set of rear shock absorbers will make.

The anti-roll bar bushes can wear and cause noise, but as yours is when driving in a straight line, this cause seems unlikely. Fiddly job!

Axles can sometimes "go bad", but unless the car has covered an incredible mileage in 4 years, I'd file this one away for later, along with the anti-roll bar bushes for the time being.

Good luck, please do let us know how you get on.

BB
:beer:

Mine does exactly the same, Volvo garage told me the top mounts on front suspension and engine mounts are worn.

Not done anything about it yet though, just living with it at the moment.

Stu.