Just changed the oil and filter on my 1989 R100GS before heading for Spain tomorrow morning - leaving at 9am.
Went for a 20 mile or so test ride as I've done the valve clearances, gearbox and final drive oils as well. When I got back the oil pressure light came on at tickover and the oil cooler is cold. Filter was supplied with the black square section O ring only, original BMW part.
So what have I done wrong/left out? I've done this job loads of times and never had an issue before.
Went for a 20 mile or so test ride as I've done the valve clearances, gearbox and final drive oils as well. When I got back the oil pressure light came on at tickover and the oil cooler is cold. Filter was supplied with the black square section O ring only, original BMW part.
So what have I done wrong/left out? I've done this job loads of times and never had an issue before.

