If the 3.5liter motor is out of time will that give you a false reading for a blown head gasket ?… In other if pressure check is taken on a motor out of time will 1 or 2 cylinders have low pressure reading?
Q.2 What are the possibilities that all 24 valves on a 3.5 liter engine be bent from one day to the next
Yes an interference engine such as the 3.5L DOHC can give a low compression reading that can cause a false diagnosis. This is cause by the valves being open at the wrong time and or bent.
The possibility of all the valve being bent are high if the car died while driving. This happens quite often when a timing belt breaks. The engine is already turning at over 1,500 rpm and internal parts continue to spin out of time with no belt to keep them in time. The valves hit the pistons and bend.