Greetings Poncho 38.
If the first test that is done if you have not lowered the camera is to see if in the morning or when the engine is very cold you can see if bubbles are out of air by the radiator (it has to be well full of fluid either water or refrigerant) This is a sign that there is gas leakage by the cylinders and it is a sign that there is the broken packaging, or folded chamber.
Now if the camera is already outside there are a technical form of verifying it.
The ideal is if there is a precision rule (it would be a matter of looking for a rectifier that had it since it is not a common tool. Eye I do not want to generalize but in which I asked any and that I had them and that gave me to think) in short whether you have the rule, the rule is placed in diagonal from the upper left corner of the camera to the lower right corner and with a leaf gang. The rule, which should not be greater than 0.1 mm if it is greater, must be rectified, then the procedure is now repeated from the lower left corner to the upper right corner (in cross) (eye this procedure is for motors in general the ideal would be to look for the manufacturer's manual and indicate what would be the exact measure, this is in case of not having the manual).
If given the case, the rule is not achieved, a glass may preferably be used greater than 1cm thick but trying to pass the leaf calibrator, through the center of the chamber and should not be greater than 0.2 mm.
Well I hope I helped you if the explanation was not clear please tell me, I am at your order.