My S3 started doing a a squeaky noise when starting up,not always,but very often when cold.A friend at work said it must be the cambelt.Not sure since the car's only done 40k miles,though it's a 2001 model.Local specialist (mastertechs,South London) quoted me £670 for major service+cambelt and water pump replacement.The cambelt hasn't been changed before and i read elsewhere that it should be changed every 5 years regardless of mileage.Please advice/is price right?