Help needed with PCV routing and new catch can - blowing oil out of oil pan!

Detroit_Muscle · Oct 8, 2015

I recently purchased the new BMR catch can and installed it. After ~20 miles of driving I thought I smelled something burning...looked under the car and see the exhaust and everything else from the oil pan back, is soaked in oil.

I have everything plumbed per their diagram below which I pulled straight from the BMR thread, including the check valve on the 'outlet' line and the hose between passenger side valve cover and intake. Can you guys take a look and see if you see any issues with this configuration? I have no idea if anyone else has bought this catch can and installed it yet, or not. I am sure BMR will say they have sold tons... My guess is that there is something pressurizing the crankcase, but I am not really familiar with our PCV system. Note: check valves are installed in the direction of air flow, with the arrows...

Input wanted! Nothing else changed besides catch can install and the oil geyser issue that could have contributed. Thanks.

dBomm · Oct 9, 2015

Make sure the check valve in the output line is facing the correct direction, and that it's functioning. If it's facing the wrong way or not opening, the check valve in the intake line will prevent the engine from venting and pressure will build in the crankcase. You can actually remove both check valves - they're not needed.

Detroit_Muscle · Oct 9, 2015

I am being told by BMR that the check valves are to be oriented in the direction of airflow indicated by the arrows on the diagram. I questioned the line on the intake as well, their response was: "The hose from the air intake to the valve cover allows fresh air to cycle through the motor while under vacuum from the motor. But it has the check valve to prevent it from being a vacuum leak."

dBomm · Oct 9, 2015

Detroit_Muscle said:
I questioned the line on the intake as well, their response was: "The hose from the air intake to the valve cover allows fresh air to cycle through the motor while under vacuum from the motor. But it has the check valve to prevent it from being a vacuum leak."

There is no source of engine vacuum on either side of that line, so how could it be a vacuum leak?

6468 · Oct 9, 2015

I would remove the check valve from the line that goes from the MAF tube to the valve cover. That line allows fresh air to enter the motor for pcv and to vent excess crankcase pressure under high load.

.02

DJ

Lil mikey · Oct 9, 2015

Aren't you then letting in unmetered air in? It will them pop codes thinking it s seeing a vacuum leak.

Retrax · Oct 9, 2015

Is there any oil in the can? And which hose/fitting is the leak coming from?

dBomm · Oct 9, 2015

If he's building crankcase pressure, the leak could be coming from the rear seal or valve covers, instead of hoses/fittings.

Detroit_Muscle · Oct 10, 2015

Thanks for the feedback guys. Removing that check valve does seem like a logical answer but it's not the problem according to the manufacturer, who also claims others are running this setup now without issue.

So if the passenger valve cover is pressurized instead of under vacuum, wouldn't I start to suck in oil into the intake stream? When I pulled the hoses apart I didn't see any oil residue on that check valve, only some on the outlet hose check valve (as there should be).

dBomm · Oct 10, 2015

Detroit_Muscle said:
So if the passenger valve cover is pressurized instead of under vacuum, wouldn't I start to suck in oil into the intake stream?

Not if the check valve is working. That's why it's there.

Help needed with PCV routing and new catch can - blowing oil out of oil pan!

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