Another broken dipstick!
I managed to break my dipstick today. I think I can shed some light on how it happens. This forum and a Google search shows it to be a common problem. I also happened to look at an A2 which had a broken dipstick before I bought mine.
I changed the oil yesterday and went to check the level with a view to topping up to the max at lunchtime today. The engine had cooled down after my morning commute, and the air temp was about 10C, which may be relevant.
After wiping the dipstick I re-inserted it. As the plastic end bit negotiated a bend in its guide I heard a click & immediately realised it had probably broken; withdrawing it confirmed it.
Having previously read here that having the plastic end in the sump is nothing to worry about (thanks Mike) I felt I had no option but to push the dipstick back in to push the broken bit down into the sump. Later on I thought it would have been worth starting the engine to see if it would get blown out. Too late though
Obviously there's a design flaw, but a couple of thoughts may help others avoid the problem. I think it's caused by a weakness in the plastic end bit, which can get over-stressed and cause it to break off as it's pushed around the curve of its guide.
A contributory factor could be low temperatures, causing the plastic to become more brittle. Another could be that the flexible dipstick sets in a curve, to some extent, over time. I find it's easier to insert in one orientation than another because of this. In fact when I broke mine I felt I'd started to insert it "against the curve" and had just decided to pull it out a bit and turn it when it broke.
People can do 2 things to help prevent theirs from breaking:
1) Check levels when warm, as the manual states, a few minutes after the engine has stopped. The plastic will be less brittle.
2) Check the set/curve of the dipstick and insert with the curve rather than against it.
Mark