I bought a 2005 Scion tC 5 speed about 2 months ago, and over the past 1500 miles since the last oil change, it has lost nearly 3 quarts (only reason I noticed is because oil light came on only when I hit the brakes). I knew of the issue about piston rings on some year models, but my 05 shouldn't have been affected. Yet, when I loosened my oil fill cap, it rattled around like maracas, and when I pull the cap off completely, it sprays oil lightly everywhere. The car only has 141k miles, and otherwise seems to run fine. No audible knocking, and the check engine light is only on for the missing catalytic converter, and it doesn't feel down on power. I don't have any visible leaks on the front side of the head gasket, but I can't see the rear side without pulling off some stuff. There's also no puddles that I've noticed under the car, so I'm just confused at this point. I'd think that I'd see excessive blue smoke given the amount of oil I've lost, but I haven't seen much of anything leaving the tail pipe. Just soot caking the tailpipe and what smells like unburned fuel, general cat delete issues. If anyone else has had this issue and fixed it, or knows what's happening, I'd greatly appreciate an explanation. If it's a head gasket issue, I'd consider having it replaced, but if the engine is toast, it wouldn't be worth replacing. It would cost the same as what I payed for the car originally. 😞 Video below of oil cap and spray.

https://drive.google.com/file/d/14t3...w?usp=drivesdk

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Maybe get crazy and try a compression and leak down test and that will tell you all you need to know about rings, valves, valve seals and your head gasket. Any particular reason it's missing the cat and you're perfectly okay driving around with the CEL glaring at you?

If you're getting the smell of unburned fuel and soot in the tailpipe I can only imagine how much fuel is washing down those cylinders, which does wonders for lubrication and ring wear.

 

I may take it to a shop to have those tests done, but regarding the exhaust, it was like that when I bought it. I still need to buy a small in-line cat to keep the cel off, and I also need to get it tuned to correct the fuel maps (resetting fuel trims did little to fix this). Again, all of that will be pointless if the engine is done for, but I'll try to find a shop Saturday that can run a compression test to confirm. I suspect that a previous owner may have swapped a newer engine into the car before selling it and to the guy I bought it from, or perhaps my seller knew of the issue and failed to tell me. Either way, I was a dunce for not checking for blow by before I bought it. I guess you live and learn, eh? But should the compression come back good, what else could be my problem? I'm not seeing oil in my coolant or vice-versa, so there's no apparent head gasket leak between the two channels. I probably need to check the pcv valve. I expect it to be full of oil given the blow by, but I haven't checked to see if the valve itself has failed. I just had the same problem on my Dodge Dakota, and if I am having the same issue here, that's just dumb luck.