If you are in a warm climate area such as Florida or any other states where freezing temperatures do not take place you do not need antifreeze .. however antifreeze mixed 50/50 is better for your complete cooling system than pure water.
126,000 miles on a 4.6L V8 is really not bad at all.
No compression on cylinders 1 & 5 could possibly be bad exhaust valves on #1 and#5. If you hear a popping sound from within the engine it very well could be a intake valve.
If you hear a popping sound from your exhaust it very well could be a exhaust valve.
If you are seeing white steam coming out of you exhaust you could have a cracked head gasket.
The 4.6L Firing order is 1-3-7-2-6-5-4-8 so that would possibly mean both head gaskets are bad because cylinder 1 (Standing in front of vehicle looking toward the windshield is on your "left side" of the engine and cylinder 5 (Standing in front of vehicle looking toward the windshield is on your "right side" of the engine.
(See Diagram Below)
Usually the crack in the head gasket would be right above or close to a specific cylinder where the coolant can enter and create steam when burned up by combustion, and exit through the exhaust.
I strongly feel the engine with 126,000 miles does not have bad head gaskets unless you overheated the engine and continued driving it.
I would advise you find another shop and see if they tell you there is no compression in cylinders #1 and #5.
Usually a misfire is often solved by cleaning the M.A.F. (Max Air Flow) Sensor with spray Electronics or carb cleaning solution. Mak sure it is completely dry before putting it back on. Hopefully that will solve the problem of #1 and #5 misfire.
Wednesday, November 18th, 2009 AT 11:30 PM