Noises - finding source

[CovKid]

Quite often, owners report unusual noises coming from underneath the vehicle which are difficult to pinpoint so I thought it might be useful to put together a list of possible culprits with help from other members. It could prove to be a useful resource that we can WIKI once its done.

I'll start with CV joints which can clonk like something is loose underneath and sound worse at low speeds or when there is no load on the driveshafts. 9 times out of ten, noises from the back are CV joints even if the noise doesn't sound the way you might expect.

Loose bolts on CV joints (inner or outer) can also cause a clonking noise, although not for long. Eventually the joint will part company from the flange with a bang as the last bolts snap on pull away at a junction!

Euro Car Parts say about CV joints: "The cv joint is found on either end of the driveshaft usual indication of failure is a clicking or grinding sound when turning. Inner joint failure may cause vibration or clunking when accelerating or declerating." - can't argue with that.

More suggestions?

[Cruz]

Gearbox mount excessivley worn - Vibration or loud rattling when setting off or reversing. Like the van is going to shake to bits. Replace with Brickwerks powerflex mount.

Remnants of rusted away brake disc stonechip covers - I had a noise when turning once from the front wheels and it was the remaining bits of the front brake disc stonechip covers that were rubbing. Just bending the remaining fragments in the right direction solved it. Still not replaced them

Loud metallic rattle from rear on uneven road sections - possibly one of the the pigtails on the rear springs has snapped. Mine snapped once and the remaining spring dropped down to sit nicely on the trailing arm but the broken pigtail part was trapped inside the spring and rattled like mad.

Slight tapping noise from front wheel arch - The bracket from the front mudflap to the chassis had come loose and the air disturbance from driving made the bracket drum against the chassis

[bicolour]

vibrating noise at around 45-50mph from front still tryin to find?

[jrt]

A strange grinding/rattle coming from the engine bay-knackered water pump.
When we bought our van i think the pump was already on its way out because the engine always sounded strange but i didn't know any better. Started by replacing the perished silencer gaskets which made it quieter but it still wasn't right. It was later on when changing the oil i noticed drops of water at the base of the pump, slipped off the belt and ran the engine for a moment and the noise had gone.
David.

[82JEW75]

One important piece of information when trying to locate the source of a noise is whether it is related to engine revs or to road speed.

Wheels, wheel bearings, brakes, driveshafts (CV joints) and some parts of the gearbox rotate at road speed. If a noise gets faster as the road speed increases, then these are the first places to look.

If the noise can be made to vary with engine revs, then it's coming from the engine, ancillary belts (water pump, alternator), clutch or some parts of the gearbox.

[ghost123uk]

Creaking / squeaking when going over undulating surfaces / bumps = usually upper, inner wishbone bushes. Lubricating them rarely works."Workshop job" really as it involves a grinder and a welder (to remove / replace the locating tangs) and much care not to upset the suspension geometry.

Whilst often not an MOT failure it IS worth doing as the van feels so much nicer to drive when it doesn't sound like a creaky old thing !