5.4L f150 dead cylinder

Hey guys! Was wondering if since my #6 cylinder is dead.A: do I need a new motor, or.B: could it be repaired? Does the repair or new motor out weigh each other in cost?


Dead means…? If no compression, is it a valve and/or piston rings/cylinder bore problem? Diagnosis needed before a wise decision can be made.

Low compression

First spend about 100.00 dollars to get a shop to diagnose the real problem . That way you will have an idea of repair cost . Or you could have the codes read and post them here other wise all you can get is a bunch of wild guesses.

Had it looked at. They said 6 was dead.

The reason(s) for that can be discerned by a competent well-equipped shop.

Only code that read was 1 and 7 coil pack bad

Perform a leak-down test on cylinder #6 to determine why it has low compression.


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Did they not offer any repair advice ?

They seemed to be on their game. He said the meter was messed up and still came up with possible.new motor outcome nothing else.

$89 bucks for nothing but a motor swap.costing 4k+. 8f i got the motor, it would be 1,700 install

Cant be a dead end to this problem with just a motor option

Getting spark and fuel. Everything good other than cylinder outcome after compression test

Not sure what you are trying to say here. But if you furnish a motor used , rebuilt or crate if it is bad then they do not have to warranty it . I think you need a second opinion but it will not be free as all places will charge a diagnostic fee. Only you can decide if you want to spend money on this unknown year and condition of the truck.

99 140k on it. Second opinion was here. I’ll get a 3rd one at another shop. Thanks

I’m saying what my original post stated. Got nowhere which is ok .

There may be options instead of a complete motor replacement. Check around.

Will do. Thanks

As tester said, do a leak down test, may be a bad/stuck valve.

You could have low compression because of problems in the block such as bad rings, damaged cylinder wall or hole in piston. These would require a rebuild or a different engine.
You could also have a valve train problem, anything from the valve to the camshaft, or a damaged head itself. Less expensive,

The third possibility is a bad head gasket. Less expensive.

Unless the mechanic knows the problem is in the block, he didn’t do a complete diagnosis and is being irresponsible to tell you you need a new engine.

I don’t know about other areas of the country but we had junkyards here that would sell you used engines with a 30 day guarantee and install them pretty cheaply too. The one I used to deal with went out of business a few years ago but I think I could still find one.