Interesting. KIA’s initial diagnosis only mentioned that Cylinder #1 with 110 PSI was horrible, like you say, and ended up being the one with lowered piston and that was eventually determined to be a bent rod caused likely by it being hyrdolocked.
I just checked kiatechinfo.com and you’re absolutely right - the standard for my engine should be 184 PSI, so I see what you mean by the others going downhill.
I don’t see the acceptable range listed. KIA’s service made no note that 150 PSI on the other cylinders being abnormal or unacceptable. The Check Engine light did not come on until the problem with Cylinder 1, so I assume where 150 is low - it’s in the acceptable range to the car’s computer and 110 PSI is definitely not. I will certainly ask. Thanks for that nugget of information.
To answer your questions, I bought the car with around 30k miles. I’ve put around 24K miles on it.
Since I’ve had the car:
Regular oil changes (around 4000 miles each time, I go with the mid-level option presented by the oil change places I go: Jiffy Lube or Midas, and now this shop that I won’t name, yet).
I always fill the gas tank fully with mid grade gas from the same station if I am in town and I’m hardly ever out of town with the car…
I’ve never had an overheating problem.
If there was a piston ring problem would this have been noticed by KIA’s shop when the valve cover gasket was removed and they checked the camshaft and valves? (Paperwork says this all was OK) I don’t know where the piston rings are located. Or would this have been discovered when the piston with the bent rod was removed? (I have talked to KIA about the situation after they pulled it all a part, but since they haven’t finished I don’t have paperwork in front of me)
If a piston ring problem existed could this have caused the bent rod? Would there have been other symptoms? Such as if there was a head gasket crack (there was not in my case) and this would show up as radiator fluids leaking into the combustion chamber?
Would the low PSI show up on both the “wet” and “dry” compression test? I don’t know what either place used and will ask about this. If the compression was checked (either method) by the initial service center on a Saturday and less than 50 miles of in town driving later checked by KIA - could the results change from a PASS to FAIL?
Apologies for any elementary questions or wording and I am extremely grateful for all input. I can do more research based upon all this information if necessary.
Update - doing some more reading here, and it sounds like if I had piston ring problems that a) I would notice a lack of engine power (did not notice this) b) I would go through a lot of oil (no oil change service has told me I was low on oil) c) smoke would be coming out the exhaust (also have not noticed, or been told by others they have noticed)
I could be wrong, though, so additional feedback is appreciated.