I read the article in Sowetan of May 19 about DIY service being the best option when a car is at a certain mileage.
I drive a 2004 Polo Classic with about 185000km on the clock. I experienced the same "clonk" that Tshego mentioned, but I also experience the following problems:
l the steering wheel vibrates when I apply the brakes at speed;
l there is a whistling sound from the engine when it is running.
I have taken it more than three times to a VW dealer and each time the diagnosis was different. Regarding the clonk, I was told that the steering rack was worn out. I had it replaced but the clonk is still there. It's not the typical clack-clack-clack sound of worn CV joints, but just to make sure, I had them checked and they got a clean bill of health. As far as the vibration is concerned, first I was told it was caused by worn ball joints and bearings. I replaced them, but the problem persisted. The second time I was told the brakes were "finished".
The third time I was told the brake discs were defective.
Any advice regarding these problems will be appreciated.
When I answered Tshego's query about the clonk in the steering, the possibility of a worn or loose steering rack did cross my mind, but I considered it sufficiently remote not to mention it.
In your case that possibility has been eliminated.
You have also replaced the ball joints, and had the CV joints checked, so these can be ruled out.
That leaves the bushes and ball joints at the ends of the steering links (the so-called tie-rod ends) as prime suspects, with the bushes on the wishbone frame, and the bearings in the strut top mount on each side as further candidates.
Take the car to an independent workshop specialising in steering/suspension/alignment problems, let them put the car on the lift and pinpoint the source of the clonk.
Don't be satisfied until they can replicate the sound while you watch from underneath to see and feel the sudden jerk in the component where the excessive play is present.
Have the wheel alignment checked after the replacement part has been fitted, so it might be best to go to a reputable alignment shop from the outset. Wheel alignment, incidentally, is one of the jobs that I would not try to do myself, despite what some people maintain.
As for the vibration on the steering wheel under braking, a warped or unevenly worn brake disc is the most likely culprit. But again you can make sure, and in this case you can do it at home.
If you remove the front wheels and get in under the car with a good light, you should be able to see enough of the discs (both faces) to examine them for signs of uneven wear or discoloured blotches when you slowly rotate the hubs.
The whistling sound from the engine is an interesting and not uncommon phenomenon. Assuming it is heard when the car is stationary, it can only be caused by air being sucked through a tiny slit or gap somewhere in the vacuum hoses or intake air ducting of the engine.
To locate the area from where it comes, use a piece of rubber hose (ordinary garden hose pipe will do), about a metre long. Put one end to your ear and probe with the other end all along the path of the intake air, from the air cleaner to the inlet manifold and along the vacuum hoses branching off the manifold.
The noise will suddenly become louder when you get closer to the leak. You can then examine the hoses and joints in that area carefully for cracks or looseness. You might have to remove a rubber duct, especially if it is ribbed, and hold it up to a bright light while you twist and flex it to see if light gets through a hard-to-spot crack.
Keep in mind that a bearing going bad can emit a shriek sound like a whistle. Bearings that have been known to do this include the ones on the alternator, water pump, electric fan, and various idler or tensioner pulleys. The home mechanic's rubber hose will again be a useful diagnostic tool in such cases.