VW GOLF WINTER TROUBLE
Q It is quite rare for me now to use my 1982 VW Golf 1.5 during the winter months, but I have needed to do so over this winter with my modern reliable car having let me down and spending a lot of time back at the dealers. What I found was that when using the Golf on a longish run, it began to lose power and progressively become slower and slower. When this occurred, I pulled over and had a look under the bonnet, but could see nothing amiss. By the time I had then got back in the vehicle and set off again, power appeared to be back to normal. Hopefully this is not a situation that will repeat itself, but I would like to know what the problem was so that I may look into putting things right again. Any guidance would be appreciated. Viam Macbeth
A I suspect the problem you encountered is one that I too experienced a few years back on my VW Passat, and one that was apparently more common for some reason on VW vehicles than most others. The problem is icing of the carburettor, and this occurs when the temperature is low and the cold air rushing into the venturi lowers the temperature to below zero, causing the petrol to form ice particles on the carburettor jets.
The carburettor on your Golf should be a Keihin, and the air filter should have a vacuumoperated flap which, when the temperature is low, will pull the flap into the cold position, directing it to collect the incoming air from above the exhaust manifold. In most conditions this will ensure it is warm enough to prevent the icing situation.
I would begin by ensuring that the vacuum hose to the flap control and the flap operation itself are all in working order, and also that the original air filter is still in place and that the hot air pick-up from the manifold is good. If the air filter and directional flap are all in good condition and operating as they should do, then you could also try a fuel additive such as SILKOLENE PRO FST – this is more directed toward motorcyclists, but is perfectly good to use in your VW Golf and will help prevent this icing.