If you have the injector out, put a SMALL amount of #1 Permatex on the injector nozzle case tip right where it goes into the main body of the injector. This will help seal off any small leak.
Another thing to check is the fuel injector return line. Sometimes the little bolt and washers come loose or don't seat up right and you can get air/fuel leaking from there. Worth while checking.
To seal up worn rings and other worn items (bearings) inside the engine, add a can of: Automotive Restore Products "Engine Restorer & Lubricant" It comes in sizes for 4, 6 and 8 cylinder engines and works for both gasoline or diesel
engines. It cost's about $6 for the 4 cylinders size can.
On your engine, I'd buy the 4 cylinder size can and use a whole can. When you do the next oil change
, you would only need 1/2 of a can. You just pour it in the engine - it mixes with the diesel engine oil. This stuff really works!! It takes about 3 to 4 hours to start working, and after about 10 or 12 hours you should see a pretty big improvement
The other thing you can do is switch over to straight 30 weight oil. Make sure it is diesel grade oil. Shell Rotella oil is excellent and you can find it world wide.
Between the "Engine Restorer" and the 30-wt oil, you will have enough compression for the engine to "cold start" without starting fluid.
When you decided to remove the head to replace the sleeves, you don't need the special Volvo tools to get the sleeves out or to put them back in IF you have the head off.
You can make a punch to drive out the old injector sleeves by grinding down a steel
punch, or have one turn in a lather. You put the punch into the injector nozzle hole and give it a few taps and the copper sleeve will come out.
To re-seat the new injector sleeve you can use a long socket the fits fairly snuggly into the injector sleeve and give it a couple of taps with a hammer until the tip of the copper sleeve comes out into the combustion chamber. Once that has happened, give it about 2 or 3 more hits to insure it has totally bottomed out in the cylinder head.
As I remember there is a o-ring that goes on the sleeve, so don't forget to put it on before you install the new copper sleeve!
Once the new sleeve is in, you have to trim off the excess that is sticking out into the combustion chamber. I use a Dremel tool to VERY CAREFULLY grind the excess off, but you could use a drill motor
with a small grinder bit.