D12D Engine Leak

Or a cracked head. Have you had the cooling system pressure check ?

 

Injector copper sleeves replacement is quite a job because you need a lot of specialized Volvo tools and a service manual. Damaged o-rings on copper sleeves lead to fuel in coolant condition, damaged thermostat (fuel eats the rubber on thermostat), engine difficult to start, not able to reach the right operating temperature (the thermostat), but not to coolant loss. EGR cooler normally behaves that way, but as long as you had yours checked already, I would try to check the EGR valves cooling circuit, i mean the coolant pipes running through the valves. A leaking pipe is unnoticeable because of the high temperature on exhaust manifold causing the leaking coolant to evaporate before reaching the pavement.