What is this piece?
03-30-2015, 03:54 PM
#1
I have a 1991 F-150 4.9 I6 300 and I want to know what this piece is. It comes from the top of the rocker cover and goes to the air filter box. That piece is leaking oil but idk what it is to get a new one. Please help!!
Last edited by BeboMonk; 03-30-2015 at 05:25 PM.
03-30-2015, 05:01 PM
#4
The PCV valve (positive crankcase ventilation) goes at a different spot. Yours is most likely not working. Worth the extra to get new PCV valves from Ford (motorcraft).
What is supposed to happen is that there is a vacuum line hooked to the pcv valve that goes to the intake manifold.
It sucks the excess blowby in the crankcase out and keeps pressure from building up in there.
Air is supposed to come in through the little filter in your air filter box, go through that hose, into the rocker cover, and get sucked through the motor and into the intake, and then burned off by going through the motor and out the exhaust.
If the suction side of your pcv system gets plugged up, then pressure builds up and it forces oil out the hose.
Also out your rear main seal, your front seal, and up past your rings into your cylinders.
Important to get it all working right.
What is supposed to happen is that there is a vacuum line hooked to the pcv valve that goes to the intake manifold.
It sucks the excess blowby in the crankcase out and keeps pressure from building up in there.
Air is supposed to come in through the little filter in your air filter box, go through that hose, into the rocker cover, and get sucked through the motor and into the intake, and then burned off by going through the motor and out the exhaust.
If the suction side of your pcv system gets plugged up, then pressure builds up and it forces oil out the hose.
Also out your rear main seal, your front seal, and up past your rings into your cylinders.
Important to get it all working right.
03-30-2015, 05:16 PM
#6
Senior Member
Being a tech, I felt I need to correct something for the OP.
In your post you ask what is coming from the top of the oil pan. The oil pan is the pan on the bottom of the engine that the oil stays in. The one on the top of the engine is usually referred to as a valve cover or rocker cover.
I'm not trying to be a smart *** by pointing this out so please don't take it that way. But if you hadn't posted a pic and asked about a hose coming from the top of the oil pan we would all be somewhat confused.
In your post you ask what is coming from the top of the oil pan. The oil pan is the pan on the bottom of the engine that the oil stays in. The one on the top of the engine is usually referred to as a valve cover or rocker cover.
I'm not trying to be a smart *** by pointing this out so please don't take it that way. But if you hadn't posted a pic and asked about a hose coming from the top of the oil pan we would all be somewhat confused.
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03-30-2015, 05:29 PM
#8
Also make sure that the hose that goes to the pcv valve is sucking air, and that little piece in the airbox that the hose goes to is a filter (should be called a pcv filter) and hopefully that will clear things up for you. You may notice it doesn't use as much oil as well.
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