Toro flow D478 vacuum pump
 

Hey, I've been searching the internet for a bit trying to figure out why there's a vaccum pump that's connected from the crankcase to the upper block on my engine. The best explanation I could find was

"The only diesel crankcase pumps I'm aware of are "crankcase exhausters" used on certain diesel locomotives (Alco for sure; uncertain about EMD or General Electric....). This is an electric-driven pump that continuously exhausts the crankcase. The blowby is pumped into the intake manifold and thence passes to the combustion chambers where it is burned.

Primary purpose for the exhauster is to reduce the risk of a crankcase explosion. It however also reduces engine emissions and helps extend lube oil life. "

Is this the case for these engines and if so, is it needed?

Re: Toro flow D478 vacuum pump
 

I found this post mention in the Archive's Previous Posts section.

Re: Toro flow D478 vacuum pump
 

I've heard that before and that was my first thought, however this vacuum pump is only hooked from the crankcase on the inlet to the front passager side of the motor, it's other ports are blocked off. I'm sure there's a chance it could have also been connected to a brake booster but why would it have a discharge line going to the engine block?

Re: Toro flow D478 vacuum pump
 

The Bendix brake vacuum pumps did have an oil pressure line and an oil drain line for lubrication, just like an air brake compressor. That small line coming off the block in front of the right cylinder head should be the oil pressure line.