4.9 Crankcase Pressure?
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Joined: Oct 2004
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4.9 Crankcase Pressure?
Newbie Greetings!
I have a '90 F-150 4.9 4spd 4x4, 90k miles, very smooth and strong (as strong as a 300 6 can be!) I'm getting a lot of oil in the air filter box, coming from the breather hose. I know enough that this could be caused by a clogged PVC valve, which I replaced and it still happens. The PVC vacuum supply hose is not clogged, I'm getting vacuum at the PVC valve with the motor running, and the check-valve rattles free. With the engine running and the PVC valve out, there's no blow-by. Strange.
Any thoughts what would cause this oil in the air filter box? It is so much that it pools in the box and drips on the ground after you stop.
thanks!
I have a '90 F-150 4.9 4spd 4x4, 90k miles, very smooth and strong (as strong as a 300 6 can be!) I'm getting a lot of oil in the air filter box, coming from the breather hose. I know enough that this could be caused by a clogged PVC valve, which I replaced and it still happens. The PVC vacuum supply hose is not clogged, I'm getting vacuum at the PVC valve with the motor running, and the check-valve rattles free. With the engine running and the PVC valve out, there's no blow-by. Strange.
Any thoughts what would cause this oil in the air filter box? It is so much that it pools in the box and drips on the ground after you stop.
thanks!
Elder User
Joined: Apr 2001
Posts: 772
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From: Glen Burnie Maryland
Sounds like the hose is partially clogged not allowing the VOLUME of air required to flow. Also the fitting at the intake might be partially clogged. You can pull a vacuum and still get pooling at the air box due to partial clogging which will not allow FULL FLOW.
Hose is cheap. Replace the hose and make absolutely sure (visually inspect) that the intake fitting is completely OPEN. Make surethe hose IS NOT KINKED when installed.
Larry
Hose is cheap. Replace the hose and make absolutely sure (visually inspect) that the intake fitting is completely OPEN. Make surethe hose IS NOT KINKED when installed.
Larry
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