Because all these engines have some blowby from the the pistons into the crankcase. Also, remember that your vacuum pump is always pulling that vacuum and dumping the air it pulls out into the crankcase also. You got any leaks? That means more blowby vapor. And that also is part of the vapor that is coming up. Did you know that you can "kill" the engine by holding that hose shut while the engine is idling. If your engine will run for three seconds before shut down, that is considered reasonable.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!