A strange one this and one I intend to resolve by fitting a pair of replacement front struts but I am curious to know the answer just the same, if there is one .
I have noticed that when the air temp is very low (close to freezing) the front N/S (left on my car) strut makes an awful grinding noise when I negotiate a speed bump and strangely is quiet when it is a relatively warm day. I have also noticed this strut seems to be weeping a little oil which is the main reason I want to swap it out.
Therefore, does the remaining oil get thicker in the cold and fail to lubricate whatever it should or am I way of the mark with my guess?
As I said, it is just my curiosity that I would like to satisfy
This is a quite common and annoying phenomenon. I did a complete front end overhaul last year and barely have any grinding noise left on the speed bumps this “winter”. Cause may have been missing damping rings between bottom spring plate and spring. These are rubber rings that snugly fit between the bottom of the spring and the lower spring plate on the strut. The VW part # is 411 411 211 (Dämpfungsring). You can still get them from VW Cassic Parts (http://www.vw-classicparts.de/). It is unlikely that the shock absorber (strut insert) will cause the noise. If oil leaks out of the strut it will slowly loose its damping function and you will notice that the front of your car will give the impression it wants to "take off" when you hit the speed bumps. At least, my car did that, and new strut inserts made me wonder where the speed bumps had gone. What a difference!
I have just spent ages translating the enquiry form to get hold of these rings as they are not present on the struts I intend to refit and don't seem to be present on the ones currently fitted.
Hopefully they will understand my poor German and I shall get a response.
Actually it is both the strut portion and the rubber portions that can make this noise. When it is very cold, the rubber bushings can creak. Also when the strut is worn and has water vapor within the oil you can hear extra strange noises as the ice is forced through the orifices in teh valving. The most common cause of creaking when very cold is teh stiffening of teh upper sealing ring around the shaft. This coupled with poor oiling of the shaft. If you want to see if this is teh problem....take some light mineral oil and oil the shaft lightly above the seal. If it goes away or diminishes for a short period....its the seals. Ray
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