Misfire cylinder number 1 loped at idle seemed fine while driving, 79,000, dealer swapped coils and plugs around problem stayed so they punt a new injector on that didnt fix it now they say that bore scope revealed a crack in the top of the piston but you cant tell its a crack just by looking at a pic according to the service writer, still hasnt been shown to me, im very skeptical no pinging no knock no explanation other than he said must be a manufacturing defect,

 

The same thing, symptoms and all recently happened to a friend's Ford F250 truck, dealer stuck a new motor in rather than fix it!

 

Hmmm... So if it's cracked to the point that it causes a problem, then you would have a ton of blowby through the crack pressurizing the crankcase. If you take off the oil filler cap, do you feel a lot of air blowing out of it? If not, I am skeptical that's the problem, especially since the alleged crack is too small to see.

 

. 30k for a new engine 15k for a used engine. I feel like fixing the problem cylinder and maybe doing a timng set makes the most sense, i wanna know what the compression numbers are i wanna feel the blow by i wannna know fuel pressures i wanna see this crack for myself, i will post any new info as it comes, any knowledgeable helpful info would be appreciated,

 

I have got my hands on an endoscope and will make my own determination soon. If the cylinder bore is damaged i will be searching for a mustang engine and trans to replace it with.

 

Is that likely to fit? By the time you get all the additional elements to work you'll have spent more than the replacement cost of the car.

 

Compression is escaping thru one of the exhaust valves. Now beginning the process to remove the head. My own bore scope pics look nothing like what i was given by the dealer.

 

Very interesting. A big job to remove the heads on these engines. Are you doing it yourself? Your engine bay is going to look like that guy's stomach after the alien popped out of it, but at least you'll be able to fix the problem.

 

Difficult to tell from the photo, but it appears something was bouncing around in that cylinder and eventually damaged one of the exhaust valves upon exiting.

What was the condition of the spark plug when the dealership Technician swapped plugs and coil units around?

 

Yeah I'd agree with this. it looks like that cylinder's had something in it that it shouldn't have - that looks like a load of small indentations in the top of the piston. Pulling the head is going to be necessary at this point anyway, but I'd be interested to see what's happened to it and the exhaust valve.

 

#1 forward exhaust valve guide worn causing valve to stick open, contact with piston apparently very slight because of the lack of any marks on the piston, but none the less the valve is bent enough to not seal. Cylinder walls look good, chain guides have the indention from the tensioner andh are getting replaced

 

Piston good to go then? Nice!

 

Sad that these "pro" mechanics would make such a rookie mistake on diagnosing the problem with this engine. If only they would take 5 mins to google the symptoms, they would have known it wasn't a cracked piston.

It's a very different job to repair a valve than a cracked piston.

 

Christopher, are you doing the work yourself or is a dealer/independent doing it?

 

Lap a new valve in and send it

 

Well I have found the reason for the bent valve. Too crunched up to determine what it was but its not magnetic,, Probably a small washer,,, Much too my dismay all this work is being performed by yours truly in a carport no less as i recently purchased a home and haven't built a proper garage yet. On a good note the head is back and ready for installation,,, Now the part where i ask for advice,, Rewinding the clock, Purchased car used from second hand dealer in late Jan. 2019 ,, in to local jag dealer for oil change just before a 1400 mile drive to orlando disney for vacation,,, arrival in orlando day 1 A/C quits, no big deal head straight to nearest dealer, Jag aston martin in orlando, get loaner and fast foward last day of vaca car is finished new compressor installed,, drive home next morning,, arrive home 3 days later this whole mess ensues,, Next course of action?

 

This is all very confusing for me. Where did you find that debris? In the catalytic converter?

if you don’t know where it came from, how do you know there isn’t more debris in the other side of the engine? I would want to positively identify the source before calling this job done.

Most metal washers are magnetic, so that doesn’t make sense that it’s a washer.

Are you suggesting the people that fixed the AC are to blame for the debris? They most likely had to take off the air boxes to do that work.

 

Those 2 pieces of metal came out of the converter. Retracing the facts leads me back to the dealer who repaired the A/C. Now im considering the likelihood of those responsible righting the wrong.

 

Next steps, Contact a good lawyer, let car sit for a probable lengthy amount of time. Or press on with the repairs, things to consider,,, Costs associated with each, length of time,,, plausible outcomes,, basically im asking a what would you do type of question.

 

Press on.

You’ll have a 1% chance of proving it was the dealer’s fault. They’ll argue the engine worked just fine all the way home for you and it’s very likely unrelated to them.

Plus you’ll have to travel to their area for the court proceedings.

You might give their management a call and see if you can milk some money out of them, at least a refund for the work they did, but you’ll have to threaten to blast them on social media.

My cars are very reliable because I keep them out of the hands of mechanics. Chances are they cut corners on your AC repair and it will probably fail again in a year or 2. Mechanics know that about ACs and laugh all the way to the bank knowing you’ll never pin a future failure on their bad work a year or two down the road.