I have a 2011 Mustang GT with 80k miles on it. I purchased the car new. I maintain the car very well and have added some mods to the car over the years. Over all this is probably the best car I’ve ever owned. Around 50K miles it started burning oil on hard acceleration off the line and when hard down shifting. No oil burning, that’s noticeable, while driving or on start up. I’ve been researching this for the last couple of years and can not find an answer. I’m now adding 3 to 4 quarts of oil between 5K oil changes. (8 quart opacity). I don’t think its the rings and that it may possibly be the intake valve oil seals. The pvc system is completely disconnected from the intake manifold (via catch can and pump) so it’s not coming from there. My plan is to put performance cams in the car soon and also change the valve seals at that time. My hope is you have the answer, no one else seems to know other then speculation. This is a problem in the same year with many of the Mustangs according to the mustang forums. Thanks for any help.
Could be stuck oil control rings, in my opinion. This will not affect compression, so a compression test will not help you there
If so, there are products out there, that claim to help free up stuck rings
Why did you disconnect the pcv system?
Well, yes, the early Coyote motors seem to have excessive oil consumption with little consensus beyond a poor functioning PVC system. Ford doesn’t even consider it excessive unless it exceeds 1 quart per 1000 miles. You don’t use that much AND you’ve disconnected the PCV system. So hmmm!
As @db4690 says, stuck oil rings can’t be determined with a compression (or leakdown) test. Bad valve oil seals have the symptoms of a blue cloud after idling for a moment and then driving away or at startup. You don’t have that either but I’d replace the valve seals if you are swapping cams and springs just because you are already there.
So stuck rings sounds like a real possibility if anything is wrong beyond a bad piston design. Try a little Marvel Mystery Oil in the crankcase. I have a friend that swears by it. Seafoam in the oil may work, too.
BTW, my 2013 Coyote doesn’t use any oil at 57K.
I’d say reduce/fix the oil consumption before swapping in a hot cam
Thanks for the input.
I always disconnect the pcv system or at least add a catch can too it. Don’t want oil/water going back into my intake (another story). The only way to see if its the valve oil seals, that I know of, is to replace them, so I figure put the cams in it while I have the old ones out. If that’s the problem great, it’s fixed and I have a few more hp, if not, I still have a few more hp lol