Hi, I have a 205 expedition that was running rough diagnosed as a fuel injector that was pouring gas into the cylinder 4. they replaced it and now they say that there is no compression in 4, and either a bent valve or a hole in the piston. they want to replace the engine for $7000. the vehicle is in excellent condition and I would like some advice. can the piston be replaced for less? Am I getting a good diagnosis from the mechanic. Thanks for any help on this.

 

There is a little more that can be done to eliminate other possibilities.
It involves removing the valve cover on that side(passenger) and actually confirm that the cams are OK and that there are no broken valve springs.
How many miles are on the vehicle?

 

it is a 2005 with about 210,000. would it be worth paying the mechanic to check the valves and then find out it was a hole in the piston. I have never heard of a hole in a piston. I would think the most probable cause was the valve?

 

Most times if a valve bends, it sticks in the valve guide, or hangs open a bit and there will be accompanying noise from the increase lash or valve clearances.
The concern during over fueling is 'washing out' the rings and piston skirt of lube oil, causing a scored cylinder/piston/piston rings etc from the lack of lubtication. Or,, if a significant amount of raw fuel is being dumped into the cylinder bore, 'hydro locking' the cylinder (can't compress the volume of liquid) and bending a connecting rod, possible piston failure, or failing a head gasket from the damaging cylinder pressure.
A bore scope used on the cylinder in question may prove out the reason over breaking it all down for inspection.
Or,, a cylinder 'leak down' test done.
Compressed air introduced into the ill cylinder and monitor where the air escapes from. Out the crankcase,, rings/piston (possible headgasket) OR, out the valves= air leaking in volumes out the tailpipe, or intake manifold depending on which valves/s.
If a piston were holed,, sometimes debris will be found in an oil sample taken, same for high volumes of raw fuel in the oil mix. At over 200k a replacement long block may be a better bet, but if a valve issue etc. not necessarily a death sentence for the mill as long as there's no cylinder gaulling/scoring.
A partial build may be possible,, meaning, ring/ valve/ bearing/gaskets minimum overhaul,, but the amount of work to complete the job, generally labor costs come into play unless self performed..

A lower mileage donor engine is always an option if found, and can reduce 'down time' as well.

 

Thanks for the reply, this vehicle had a recall I believe back in 2010 and it had its lower block replaced by ford. It has been a problem since then. I am taking it to a third mechanic as I do not have time to work on it myself. I already have over $700 in labor costs without any resolution. The scope solution sounds like the simple way to diagnose it, but apparently they do not possess such a tool. I tried to save money by not taking it to ford, but that was apparently a mistake.