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- FC, FE, Mazda5
I bought a 2012 Mazda5 a couple weeks ago (minimal rust, 108k miles, manual trans), and flew a few states away to buy it (not that many manuals available!). Everything seemed to be fine on the drive back to the dealership in the car, but I also had my face mask on when sharing the car with the dealer rep, so vehicle smells were hard to discern. Shortly after buying the car, I drove it 700 miles home, stopping about 100 miles into the trip to pick up a used transmission and rear diff for a project car. After getting it home and unloading the car parts, there has been a smell of slightly burnt oil or trans fluid inside the van that seems to intensify with driving. I can smell it under the hood after parking the car too, and had noticed it on the drive home (but wrote it off as coming from the used transmission).
Anyway, I went to investigate if there were any leaks earlier today, and couldn't find any - oil, trans output seals, dripping from the engine-trans face (crank or trans input seal), or torn CV boots. Looking around for the source, I opened up the oil cap and it smelled slightly burnt. More worryingly, when the engine was running, there was a strong pulsation out the oil cap hole that quickly deposited a nice oil film on my glove. My understanding was that at idle, the crankcase should be under a slight vacuum since the engine relies on that vacuum to purge water vapor etc from the crankcase. The only way that I am aware of for positive pressure to get into the crankcase would be a ring sealing failure, especially given the volume of air that seemed to be pulsing out (quite a puff, not just a slight breeze)
Is there anything that I'm missing, is this normal for the 2.5l engines, or am I a few weeks away from pulling this engine and tearing it apart?
Anyway, I went to investigate if there were any leaks earlier today, and couldn't find any - oil, trans output seals, dripping from the engine-trans face (crank or trans input seal), or torn CV boots. Looking around for the source, I opened up the oil cap and it smelled slightly burnt. More worryingly, when the engine was running, there was a strong pulsation out the oil cap hole that quickly deposited a nice oil film on my glove. My understanding was that at idle, the crankcase should be under a slight vacuum since the engine relies on that vacuum to purge water vapor etc from the crankcase. The only way that I am aware of for positive pressure to get into the crankcase would be a ring sealing failure, especially given the volume of air that seemed to be pulsing out (quite a puff, not just a slight breeze)
Is there anything that I'm missing, is this normal for the 2.5l engines, or am I a few weeks away from pulling this engine and tearing it apart?