oil pressure question

[austria3]

Hi

after I spend a few hours this afternoon reading all thread I could find to the above topic I still have some questions.
Here is my problem: On Monday my mechanic did the yearly techcheck and smogtest at my car. I also bought 2 Liters of oil for my car because the oil level gauge already reached the red field at idle, also the dipstick said the same. So I refield the missing oil, which the engine did need during the last 2000miles.

While I was driving around during this week (about 200 miles) I noticed that the needle of my oil pressure gauge only went up to 2.5 bar even when the engine was running with 5500 rpm. So I drove the car home very carfully and parked it in the garage. The next day I checked the floor for oillackes but there was nothing. So I started the car and let it warm up and thecked the oil level at the dipstick - no significant drop since the refill.


After reading a lot of "oil pressure" threads I will call my mechanic tomorrow if we he could check the oil pressure so we can figure out if the oil pressure sender is working or not.

But if the sender is OK what can be the problem?

a few things you might want to know:

my car is a '78 SC, did run 94000miles so far and the engine was never rebuilt. I used Castro GTX7 10W40 - this was the oil the pre-owner used at the oilchange 4 month ago short before I bought the car.

Thanks