Thread: Provent 200 outcome after 150,000km

@Twodiffs

How could necking down the hose cause a problem when the inlet to the can is bigger than the outlet from the rocker cover? If it was the other way round then I could understand an increase in pressure but you are reducing pressure. Smaller diameter out, bigger diameter in.

The Hilux crankcase vent outlet on the rocker cover is 16 mm. The kit comes with a single hose that is 16mm at the outlet end and 25mm at the Provent 200 inlet end. The inlet is the upper of the two connections.

The outlet of the catch can is the lower connection and that is also 25mm. That connects to the turbo inlet with a 25mm hose.

The Provent has a pressure release valve in the cap. If crankcase ventilation pressure coming into the can cannot be pushed through the filter and out into the turbo, then it exits through the cap. The spring controlling the release valve is surprisingly weak and it only takes a gentle press of the finger to open the valve. So you don’t need much pressure for the catch can to start venting to atmosphere.

One of the criticisms of catch can is that they can cause excessive back pressure into the crankcase and blow seals. I don’t know anything about other designs but it’s impossible with the Provent 200. I know for a fact it will vent to atmosphere if the filter starts to get too blocked to work optimally, because I let one of my filter service intervals go too long and I noticed an oily residue around the top of the unit. That release valve was doing exactly what it’s designed to do.

I’m not sure how you could get the plumbing wrong? In at the top side connection and out at the bottom side connection, with the captured oil training out of the very bottom into a length of hose, from which I periodically drain it into a bottle. (Some guys have a connection that drains the oil back into the crankcase.)