I've an 04 Combo (Corsa) with the 1.7DTI engine. (I think it's an Isuzu engine)
When cold or left standing for several hours the oil pressure light takes about 5 seconds to go out after starting, if the engine is just left standing for about 30 minutes or so the oil light goes out pretty much instantaneously.
It sounds to me like the oil system is loosing its prime and draining back into the sump. I'm not familiar with these engines so I wonder if this is a standard ''feature,'' or is there a one way/anti syphon valve to look at? The oil filter looks like a cartridge jobby at the rear of the engine - the last time I changed a filter like this in a car was 30 years ago on a BMC A series. I'm going to try buying a new genuine oil filter from Vauxhall, but can't believe that I've got to start mucking around with cartridge filters - what are Vauxhall playing at!
I'd be grateful for comments from those with specific experience of these engines thanks.
Julian.