When I joined this forum 6 months ago, I asked for help regarding this noise, but no one came forward with a practical solution. The noise starts immediately the engine is started and goes on for about 5 to 10 minutes. Irritating to the passengers and driver, but not loud. Happens everytime, any time of day. Now I have this solved by my techie here who went through almost all of the vacuum lines around the car and found that it was the diaphrams , 1 single and 1 double which had ruptured. He tested them with a hand pump with a pressure gauge. The only noise that comes from the rear pump now is the first buzz and then silence for the rest of the journey. Problem solved! This also solved the rear headrest being stuck upright and now they come down at a push of the button. My left outside RV mirror has been changed outright and colour coded to the body colour. This was damaged by previous owner who did a cover job that wasn't too impressive. I've resprayed my front bonnet(hood) and the bumper, side mouldings and some minor panel work . The only other job now is to replace the whole exhaust system which is making too much noise due to ? damaged insides and non-OEM parts. Will look at the engine to see if it needs a fix next year. I've spent too much already on this car. Can't get it to go any faster due to its "tiny" engine. Any suggestions like using a power chip???

1994 C180 Euro 190,000kms and still going strong. Looks more like a 1 year old car.