severe overheat
 

My wife was driving the 99 v70 xc last week when the engine shut down. Towed it to mechanic after it leaked all its coolant on the road who found a crack in the radiator. The engine runs with no coolant but is certainly misfiring. Compression in cylinder 3 is only 50 psi. I think I will pull the head, though I have no experience rebuilding an engine. Any help with how to diagnose the low compression will be much appreciated. Thank you

Need to do a cylinder leak test. Hopefully its just the gasket and not a warped head or cracked block.