Mobil 1 15w/40
 

I need to do an oil change in my 1988 924S . I have 2 x 1lt unopened Mobil 1 15w/50 and I have bought from the USA a 5lt Mobil 1 15w/50. Clearly as this oil has been disconinued for a number of years this is old stock . Am I right saying that unopened ones such as these wont cause any issues etc? Mobil 1 15w/50 is fully synthetic afaik

From http://ultralube.com.au/shelf-life-of-engine-oil/ comes these thoughts:The best way to tell if the stored oil is still good for your engine is to check the condition of the oil before you put it in your car. ISeparation of the additives from the oil is one sign the oil may not work well. If you notice clumps, gel lumps, or the oil is thicker than expected and sticky, then it probably isn’t safe to use in your car. You should also check the colour for haziness or a milky look, which could signify overexposure to moisture. If you don’t notice colour changes or consistency changes, then consider your oil safe to use.

Can you find a manufactured date on the bottle? Most sites suggest a two to five year shelf life depending on storage conditions.