We recently (2 months) change out the cylinder head (top), received vehicle back from workshop and drove approximatly 500km
and the started to stall. Try to get it to start again with no luck. We then get it back to the workshop were they tried to start it but with not luck. After investigation they saw that the injector camshaft had pack up. We replace it with a new injector camshaft and after that the vehicle start.
Since then the oil pressure is low.
Do any one know what the oil pressure must be?
What can be wrong is it the oil pump? Bearings in the engine?
Please help.

 

What makes them think the oil pressure is to low?

 

After replacing the injector camshaft the mechanic drove around with the vehicle and told us that he thinks the oil pressure is low. He then installed a oil pressure test kit.
when you start the vehicle the oil pressure is on 3 bars. when you drove around a little bit it fall down to 1 bar.
thank you so much for reading and replying.