O.K., I AM a dipstick myself, but I have a question related to reading the oil level in my '99 Octavia TDi.

Yesterday my "oil service" warning message displayed on the dash. Hmm, not due for a service for another 2000 miles. I check the oil level...bloody hell! So low that it just made a small blob on the end of the stick, didn't even reach to the hatched "measuring" section of the stick. Slightly suspicious of reading, in that the road I was on was slightly inclined, with the engine at the "top" end.

Drive 5 miles to Halfords, buy some Mobil oil with all the right numbers on it. Leave engine for 30 minutes, re-check the level : same reading. Car park seemed totally level to me.

Put in 1 litre of oil, in two glugs of 0.5 litres, with 10 minutes between. Drive to Tesco, 5 miles. After shopping, re-check level again...engine has been off for 1 hour now. Dip stick says level is at the MAX. Recheck twice. Yup, now at the maximum mark. After 1 litre? With a nominal 4.5 litre capacity?

Home again, leave engine cold for 5 hours. Measure again...says low, but safe.

Leave car overnight. Measure again...says approx. half full, lower than previous reading. Weird...surely overnight oil was likely to drip downwards and raise the reading?

The carparks at Halfords and Tesco were flat and level, at least to the eye. At home, I used a spirit level to confirm it was totally level.

What is it with these readings?

I do the usual remove-wipe-insert-withdraw moves (oooerr!) each time. I am not a total clumsy cack-hand. I always take 2 or 3 readings at a time, always insert fully.

-Why does the level seem to fluctuate so wildly? Is the measurement hyper sensitive to the levelness of the road? Is it best made when the engine is stone cold or after what sort of period?

-If I don't get my garage to re-set that "oil service" warning, will the engine management system prevent me from starting the car after some period? I know this happens on some makes.

-Was it a low oil level that triggered that warning in the first place? (Never had any warning lights, e.g. low oil pressure), or was it just that I hit a pre-set mileage? (It's certainly not 10K miles since the last service).

Any answers...hugely appreciated. Payments will be made telepathically, in Scrungian Vlaark nodules.

The oil level does seem to be very sensitive depending on the angle of the road...but you've already checked the car is "on the flat". I'd say it's best to check the oil temperature when it's cold, but make sure it's between the max and min mark, rather than necessarily on the max - on engines with turbos, the oil is pushed through the turbo's bearings to lubricate and cool the turbo...this causes the oil temperature to be quite high, hence it will expand quite a bit.

You can run the car permanently with the service warning light on - you can also reset it yourself (check the manual for instructions).

If you're on fixed mileage servicing, then I don't think you should get your service warnings depending on the oil usage - you'd get the oil warning light on the dash if it was too low. My service indicator just counts down the 1000 miles to the service though, so it sounds like it might be different from yours...

I shall await my nodules.

Rob.

Cheers for that, Rob. At least I shan't be worrying about the car not starting one morning because some chip decides I've been naughty and not taken an opportunity to enrich my local dealership.

I'll phone 'em anyway and find out why it thinks I need a service. It's never previously come up with the warning before 10,000 miles have elapsed.

Now, if only I can find out if this brand "MAZOLA Crisp 'n' Fry" was the right stuff to put in.

Awed

Oh no! The Vlaark Nodule has crashed due to speculation by George Soros! Payment deferred!