Hi i have a 740 gl 1990 volvo with a SOHC and i was wondering if i had to take out my engine head, or can it be done while still mounted to the car to replace my cam shaft seal at home or should i take it to a mechanic to be done at a shop?

my skill set of working on my car from 1-10 is a 7

 

cam shaft seals are done in place. if yours has blown, make sure you check the PCV 'flame trap' system, if its flugged up with old oil fumes, you'll blow your new seals in short order.

you'll need to remove the timing belt and the cam pulley if its the front seal.... the rear seal is behind the distributor (unless you have the rare 740 regina with a side-of-block distributor).