I'm going to do an oil change on my 1993 LT35 2.4 diesel and I believe I should replace the sump plug washer. I believe the correct one is a flat copper washer but I don't know the exact dimensions to get the right one. I have read somewhere that all VW's apart from the Beetle have the same sump plug and washer- is this correct? Not a major problem because I can always take the old one into the parts shop but I'd rather have it in advance.