A mystery.
I've found a 2009 Ford Explorer with 4l sohc engine that has 155,000 miles and appears to slowly burning away it's pistons for some reason.
It was discovered by accident, my guy was changing his sparkplugs and stuck an endoscope down the sparkpkug holes just to see what there was to see and what he saw was alarming. Spongy looking grey aluminum instead of nice flat smooth black piston tops. Lacking the layer of carbon I'd say the damage is still occurring.
He took it to the dealer they didn't believe him and offered to throw a few thousand dollars worth of parts at it.
Only time I've ever seen anything like that was pictures of natural gas engines that were being ran off untreated biogas. Heard they ran great till the corrosive stuff ate through the top of the piston and exposed the rings directly to combustion.
Aside from biogas ive heard of clogged or obstructed exhaust such as a bent exhaust pipe or plugged/melted catalytic converter can cause burned pistons and valves without giving a misfire or check engine light.
It was a trade in when the current owner bought it and so no history which seems sus. Its not burning oil and has never shown a check enginelight, sounds almost too good to be true for a ford. The Ford dealer replaced an EGR valve at some point.
I'm thinking check all or at least most of the cylinders see if they look the same on both banks, he only looked at 1 or 2 of them and if they are check the catalytic converter visually and if it looks good add a pressure port to the exhaust to check for blockage.
If the exhaust is definitely not obstructed and checks good then change O2 sensors, i believe there is one per bank or add spark plug nonfoulers to them.
I've found a 2009 Ford Explorer with 4l sohc engine that has 155,000 miles and appears to slowly burning away it's pistons for some reason.
It was discovered by accident, my guy was changing his sparkplugs and stuck an endoscope down the sparkpkug holes just to see what there was to see and what he saw was alarming. Spongy looking grey aluminum instead of nice flat smooth black piston tops. Lacking the layer of carbon I'd say the damage is still occurring.
He took it to the dealer they didn't believe him and offered to throw a few thousand dollars worth of parts at it.
Only time I've ever seen anything like that was pictures of natural gas engines that were being ran off untreated biogas. Heard they ran great till the corrosive stuff ate through the top of the piston and exposed the rings directly to combustion.
Aside from biogas ive heard of clogged or obstructed exhaust such as a bent exhaust pipe or plugged/melted catalytic converter can cause burned pistons and valves without giving a misfire or check engine light.
It was a trade in when the current owner bought it and so no history which seems sus. Its not burning oil and has never shown a check enginelight, sounds almost too good to be true for a ford. The Ford dealer replaced an EGR valve at some point.
I'm thinking check all or at least most of the cylinders see if they look the same on both banks, he only looked at 1 or 2 of them and if they are check the catalytic converter visually and if it looks good add a pressure port to the exhaust to check for blockage.
If the exhaust is definitely not obstructed and checks good then change O2 sensors, i believe there is one per bank or add spark plug nonfoulers to them.
