Hi,
You can try to tighten the bolts but in most cases they have already been tightened too much, so that the seal has been cut and leaked. The tightening torque is 10Nm.
But be prepared to buy a new gasket (A1300160221, not very expensive), clean the surfaces and tight with correct torgue. Don't forget to renew the ring seals for the bolts (filled copper seals 8,4 x 11,7 x 1,4mm, 915035000003)
...WRe