GRY9273IDI
Registered User
I have a 7.3L IDI with an 093 ATS turbo and a ZF5 Transmission on a 1992 Ford F250.
This is gonna be a longer post so I apologize in advance but I am at a loss of what I should do next.
While driving home from work I had zoned out on a long stretch of highway and realized I was still in 4th gear going 45-50 MPH and 2500+ RPM, without thinking I shifted into 5th.. except instead of 5th gear I had some how managed to accidentally down shift into 3rd gear. As I let off the clutch I realized due to the immense increase in RPM and I ripped the shifter back out of 3rd and up into 5th (I have no idea how high my RPMs got. I’m not even sure I fully let off the clutch as I pulled the shifter back out of 3rd as soon as i heard the RPM increase). I continued my drive home silently kicking myself for what I did and made a quick stop at the store for groceries. The truck was shut off for 30 minutes at most. When I came back out to the truck I tried to start it up and the engine would begin to turn over from the starter but would then sound as if it was hydro locked or something… I gave it a couple minutes while I tried to think of what could be happening and then gave it another try. Once again the engine began to turn over but then immediately sounded like the piston was getting stuck and unable to move. After a couple more tries all of a sudden the engine turned over (sluggishly) and fired up. Once I got home I noticed the oil leak from my dipstick tube had gone from an occasional drip to now spraying oil over the entire passenger side undercarriage. I decided to give the engine a Quick Look over before I went to pick up a new O-ring for the dip stick tube and that’s when I noticed my radiator had drops of oil floating inside of it. I drove the truck to work the next two days and when I checked everything again that weekend to no ones surprise the oil and coolant were both milky.
I dropped the oil and coolant, flushed both systems, rebuilt the oil cooler with new O-rings hoping that was the fail point and had no change. When I refilled both systems and ran the truck with the overhauled oil cooler I once again had an engine full of milkshake. I have since pulled both heads and found no obvious head gasket failures (one of the gaskets got warped as I lifted the head so I can’t definitively tell if it failed or not) I have however found 2 cracks on the passenger side head, going between the front 2 cylinder intake and exhaust valves (see Photos the pistons were also black with carbon rather than clean). When removing the heads I also noticed that the pistons in the rear cylinders of the engine looked completely clean; like it had been steam cleaned however the mating valves and head looked black with carbon and normal with no cracks.
My current thinking is that the crack in the head might be so deep that it allows coolant from the cooling jacket above the valves to leak down and into the cylinder causing the sensation of a hydrolock during start up and then leaks down past the piston rings and mixes with the fuel.
Does that seep possible? Can the heads be repaired? They don’t seem to be warped. Is it more likely that my coolant mixture PH may have been off causing cavitation or maybe a crack in the block that I can’t see? Could it still have been the the head gaskets even though there wasn’t a clear blow in the seal anywhere?
Thanks so much for the help, sorry it’s so long.
This is gonna be a longer post so I apologize in advance but I am at a loss of what I should do next.
While driving home from work I had zoned out on a long stretch of highway and realized I was still in 4th gear going 45-50 MPH and 2500+ RPM, without thinking I shifted into 5th.. except instead of 5th gear I had some how managed to accidentally down shift into 3rd gear. As I let off the clutch I realized due to the immense increase in RPM and I ripped the shifter back out of 3rd and up into 5th (I have no idea how high my RPMs got. I’m not even sure I fully let off the clutch as I pulled the shifter back out of 3rd as soon as i heard the RPM increase). I continued my drive home silently kicking myself for what I did and made a quick stop at the store for groceries. The truck was shut off for 30 minutes at most. When I came back out to the truck I tried to start it up and the engine would begin to turn over from the starter but would then sound as if it was hydro locked or something… I gave it a couple minutes while I tried to think of what could be happening and then gave it another try. Once again the engine began to turn over but then immediately sounded like the piston was getting stuck and unable to move. After a couple more tries all of a sudden the engine turned over (sluggishly) and fired up. Once I got home I noticed the oil leak from my dipstick tube had gone from an occasional drip to now spraying oil over the entire passenger side undercarriage. I decided to give the engine a Quick Look over before I went to pick up a new O-ring for the dip stick tube and that’s when I noticed my radiator had drops of oil floating inside of it. I drove the truck to work the next two days and when I checked everything again that weekend to no ones surprise the oil and coolant were both milky.
I dropped the oil and coolant, flushed both systems, rebuilt the oil cooler with new O-rings hoping that was the fail point and had no change. When I refilled both systems and ran the truck with the overhauled oil cooler I once again had an engine full of milkshake. I have since pulled both heads and found no obvious head gasket failures (one of the gaskets got warped as I lifted the head so I can’t definitively tell if it failed or not) I have however found 2 cracks on the passenger side head, going between the front 2 cylinder intake and exhaust valves (see Photos the pistons were also black with carbon rather than clean). When removing the heads I also noticed that the pistons in the rear cylinders of the engine looked completely clean; like it had been steam cleaned however the mating valves and head looked black with carbon and normal with no cracks.
My current thinking is that the crack in the head might be so deep that it allows coolant from the cooling jacket above the valves to leak down and into the cylinder causing the sensation of a hydrolock during start up and then leaks down past the piston rings and mixes with the fuel.
Does that seep possible? Can the heads be repaired? They don’t seem to be warped. Is it more likely that my coolant mixture PH may have been off causing cavitation or maybe a crack in the block that I can’t see? Could it still have been the the head gaskets even though there wasn’t a clear blow in the seal anywhere?
Thanks so much for the help, sorry it’s so long.
