oil level

Hey chaps, 1984 s3 diesel, ive noticed the engine burning/using oil in some way or another, i realised today its not been checked for 2 or 3 weeks, looked today, quite far below the low marker, i would have thought with low oil the oil pressure alarm light would have came on? Also going to look at whats involved with a compression test (im using asda 20/50w oil, going to buy more to top up with tomorrow, basically i can only get it from halfords, should i go for the halfords own 20/50w classic oil? Says designed for older engines?
Thanks ben

Would expect that the pressure light will only come on when the pickup sucks some air.

Hi, if the light is working, but I suppose it is on at start up? 20/50 is for most older vehicles and can't remember now if any difference for petrol or diesel...old age affects the wassaname...erm fingy

I use 20w/50 in my 1981 diesel. Seems to like it.
I use Millers oils as it claims to have beneficial additives but have also used Halfords own brand (which I was told was rebranded comma)

No idea about the light. I would have expected pressure to drop if it was that low but it seems not. If you're using that much oil you might want to switch your rear fog lamp on

Ok well ill pick up some halfords stuff today, and will have to remenber to check the oil more often, also the pressure light does come on at start up, so i know it works

I have run my series 3 diesel on 20/50 for 3 or 4 years now. Sometimes 15/40 in the winter months to help with starting. It used to burn/leak a fair bit before rebuilt.
When mine was low on oil the oil light would come on under heavy braking, yes I have got one that stops! As for oil when it was getting through a bit I used Wilko or Asda cheap 20/50 I also used the same oil in my VW passat which used a litre every 300 miles from 30000 to 135000 miles or so when I parted with it.
Now that I have rebuilt the engine I am using Halfords 20/50

The oil light comes on on most when the level is low and you break hard or downhill for a period. If its not it might be worth checking that your dipstick is set correct. On one of my older motors someone had replace the dipstick and I was regularly overfilling which was causing it to burn oil and generally doing it no good whatsoever!

How do i check if the its set correct?

Not sure how to check if dip stick is correct, I suspected mine when the light came on under braking so next oil change I put the 11 pint in as the book and the level on the stick looked OK.

Hmm not a bad idea, I honnestly haven't noticed it running bad or hot on the differnt oil levels, for now ill belive it, but at oil change I will do as suggested, thanks

It's not a warning light, it's a notification light that you've lost oil pressure and you're engine is now fecked. It's a bit like a heart attack warning light, not something you'd want to come on really.

That is an overstatement, the oil light comes on if the pressure goes down below a set point. That can be either because you've run out of oil which is bad or you've momentarily lost pressure because some air was sucked in, low revs or oil is getting a bit thin: non of these are too bad if the situation doesn't last for too long (a few seconds at low revs will do no harm and is no cause for panic). All the parts are no covered in oil so there isn't a huge problem, The point where the engine has a really hard time is cold starts in the winter. It takes a few seconds for the oil to start pumping out (after the oil pressure light has gone out) and to keep the engine from stalling you've probably had to pull the choke and start a fast idle...