Hi all, 1995 e34 525i 5 speed
I want to install a catch can but does this model have a CCV/ PCV??
I searched and can't find anywhere if this car has a CCV. The car burns a quart of oil every 1000 miles. My e46 did the same thing and I installed a catch can and all was well. I want to do the same thing with my e34.
Thanks in advance!
It has *a* crankcase ventilation system (not totally sure what on an M50), but it's nowhere near the same league of complexity and PITA-ness of an E46. Pretty unlikely replacing it will help with oil consumption in my opinion unless you're seeing heavy smoke from the exhaust. On the M60, the worst case is usually a bad idle from the broken vent valve becoming a vacuum leak.
M50TU crank breathers are incredibly simple, and it isn't a PCV valve setup in the same way that most modern cars are. The M50TU is just a series of wide passages in the valve cover with ported vacuum creating a low pressure source for the crankcase. This vacuum pulls aerosolized oil and vapor through that black plastic connector at the top front corner of the valve cover, where it is then pulled through a line to the intake boot in front of the throttle body.
It is a very simple system, and the only way that it can clog is if that line immediately before the intake boot fills up and doesn't let pressure through. The only time I've seen this is when there was residual coolant in the oil and that tube was full of emulsified goo, and even then, it didn't cause oil burning. It just blew oil out past the valve cover, dipstick, and front main seals. This was immediately after fixing a cracked head, so I blew the vent hose out and changed the oil, and have had no issues since.
If you really think it's the issue, disconnect the line to the intake boot and put a cap on the intake boot elbow and go for a drive. It will idle a bit rough. If it stops burning oil, there may be a correlation, but more than likely you won't see a change.
Thanks for the info. So basically I can put s catch can between the valve cover and intake boot to reduce aerosolized oil going into the intake and just allow vapor. At least the catch can will keep the intake free of aerosolized oil.
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