Low oil pressure
 

I have a Boxster 2002. I replace the oil separator for typical withe smoke issues.
Today I took the car for a test drive and it stop with a low pressures warning sign.
The car has W5-50 and it was change last mont.

Any recommendations or explanations for this new issue?

Porsche mechanic also mention he change the o ring from one of the vacuum pumps because he observe a leak.

Start by checking your oil level with the dip stick. If you are low on oil, top it up.

Next check your coolant and the oil on the dip stick to ensure that there is no mixing of oil and coolant. If there is intermix you oil cooler may have a leak, or less likely you may have a head gasket issue or cracked head. Job for a mechanic.

If there is plenty of oil and no intermix you are looking at a bigger job. The oil pump may be worn, or the pressure relief valve may be defective. Another possibility is that the bearings are so worn that the pump can't maintain pressure when idling. Again, a job for a mechanic.

Good luck!