2013 MB GL450 4.6 TWIN TURBO ENGINE VOMPRESSION PROBLEM
I'm new here

Thanks for this web I think this will help me.
I bought 2013 GL 4.6 TWIN with 128xxx miles and engine has misfire. tried put new spark coil etc. to eliminate problem but still nothing. so, decide check compression. cyl 5 cyl 7 and cyl 8 has very low compression (6,8,6).
I would like to know
"What is problem and why the engine like this with small millages has low compression if in not overheating or driving without oil " - is any recall because when i looking now is a lot of this car with engine problem but mostly 4.6
second think - because engine for this car is very expensive almost same what I paid for my car can I buy engine from 2011 (is cheaper) GL450 4.7 and swap it? Is same motor mount bracket? the computer plugs is same - plug and play? (I can buy engine 4.7 with computer ECM)
and also, my transmission will work?
Please give me any idea.
two more think - if any one maybe repairs this engine and know maybe I don't need switch engine and only replace any parts like valves seals maybe this is problem? maybe cylinders are good and need only piston rings? please help.
if I need exchange head did I need remove engine from car or not?
thank you







