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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22903
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a Fiat Punto Grande, Reg. March 2009 with only 26K miles.When

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I have a Fiat Punto Grande, Reg. March 2009 with only 26K miles.When driving over uneven drain covers and uneven surfaces, there is a noticeable knocking noise from the front left wheel area. Otherwise OK over most normal road surfaces. The anti-roll bar bushes have been assessed as OK and do not need replacing. Indeed, everything in the suspension looks and feels OK, according to the local garage. Both I and they are now scratching heads!
Have you come across this characteristic before and what was found to be the cause and hence point to a solution?
Hello I'd say that this could be a worn strut top bearing , which you can test for by holding the spring by hand and have your assistant move the steering from left to right with the wheel on the ground - a worn bearing will feel 'notchy' through the spring. The wheel needs to be on the ground for the test to load up the bearing
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Customer: replied 2 years ago.
Matt, Thank you for your prompt suggestion. I will have my local garage look at this issue today. It is most frustrating not to be able to isolate the source and rectify it! Best regards, Paul.
Customer: replied 2 years ago.
Hi Matt,
I have spoken to my garage and they confirm that they have done the test you suggested and found nothing untoward. The garage owner is going for a drive in the car this morning to hear the knocking noise for himself. His searches for information about this issue confirm that many smaller Fiats exhibit this characteristic noise. There must be an answer somewhere? The noise was not there when the car was new!
Ok i'd also check for :Worn drive shaft joint - typically these won't produce any vibration unless badly damaged but they can be noisy or 'clonk' for a long time beforehand, turn the steering to full lock and look at the drive-shaft rubber boot there should be no rips or tears in it and the suspension should be clean and dry of any grease. If you reverse at a reasonable speed with the steering on full lock a worn joint will 'click'. Worn mountings - check the tightness of the engine and gearbox mounts and their condition - this is best done by using a jack to take the weight of the engine off the mounts and seeing if any cracks or splits open up in the rubber.Also check the tightness of the mounts bolts
Customer: replied 2 years ago.
The garage owner has not yet given me the feedback from his drive of my car. I am waiting patiently, in the hope that further investigative work is being conducted. I do not wish to 'over pressurise' him and have him give up prematurely. I will let you know the outcome.
Customer: replied 2 years ago.
The garage owner did drive my car and was convinced that the rather obvious clonk noise was coming from the front left wheel area. They have now taken that front suspension apart and replaced the shock absorber and two other bearings. A retest today, with high expectation, found that the clonk remains unchanged!!
The are now to check the engine and gearbox mounts for security. Like me, the garage owner feels that the clonking is too loud to ignore.
Hello if the 'clonk' occurs when taking up load don't forget to check the state of the driveshaft joint too
Customer: replied 2 years ago.
I will pass on your info tomorrow. The garage owner is taking this clonking personally. Curing it is becoming a matter of pride!
glad to hear it
good luck
Customer: replied 2 years ago.
Went to see the garage owner today and get a status report. The LH front suspension has been apart a few times now and was yet again in bits. He is of the opinion that the clanking is too noisy to ignore and would not feel happy to continue driving it until the cause becomes noticeably worse. A number of parts have been replaced, but not yet cured the problem. He will drive the car himself again to assess the latest work and whether there has been any change. All the possible sources that you have mentioned have been viewed and tested for security. Many thanks for your help Matt, which is much appreciated.