2006 Ranger 2.5 Duratorq
 

I have a 2006 ford ranger with a 2.5L diesel and I have this engine noise that kind of sounds like an injector sleeve has come loose? or something like that it has an engine knock that is there more so at start up but is there all the time. It dosen't increase or get louder with engine rpm. But it is a deep knock noise it only has 77.000klm on it. I've learned that some small shop had put a head gasket in it which scares me. I'm in Haiti and don't have alot of info here. Any help would be great dose anyone know where or how I could get a shop manual book or on-line. I come from Canada with 15 years expearence as a tech there. Is there a way to check the cylenders for loose injector sleeves without taking it apart?
Please HELP!!!