- I had a misfire and the codes read a 3rd cylinder misfire on the highway. After buying new coils and plugs, I did the thing I should have done in the first place and ran compression.
- I got 150/160 in all cylinders, except for Cylinder 3, which was 0PSI both dry, and with a few tbs of oil. (The oil seemed to sit on top of the piston for a while as well, so I suspect piston rings are good.)
- I don't think it is a water jacket leak in the headgasket as I've not had any heating issues, no coolant loss, and there were no bubbles in the overflow tank when cranking.
- I don't think it is a bent valve as my timing belt is in good shape, but will endoscope to confirm.
- I think one valve might be stuck open due to carbon deposits. See spark plug, the black one is from cylinder 3

- The crankcase vent hose didn't look clogged. I will need to check the EGR system. There was a bit of oil atop the valve cover, like may be a 1/2 pint, but this could have been spillage over time from me pouring oil in without a funnel.
- Based on the oil burn and 0 compression, I suspect either a stuck valve or burnt valve.
Next steps:
- I will run a leak-down, and endoscope
- I've read about fully filling a cylinder with solvent, then turkey basting it out to clean both the intake and exhaust valves.
- Ive read the "rev the engine for a few minutes" technique in the event of a stuck valve. I'll give this a shot.
- If the endoscope shows an intake valve issue, I'll likely remove the intake manifold and introduce solvent that way, and also check for leaks at TDC
Am I headed in the right direction? Looming over me is the idea of a head removal and replacement, but I'd like to do some more less-invasive diagnosis, and perhaps find a less-invasive resolutions (perhaps optimistic, but also planning for the worst).
Clearwater does not have any S60 2013 heads. Where else can I look?






