The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Inspected Condition `\ :

dsraven · 04-06-2017, 05:37 PM

without seeing a pic of the engine i assume it should be similar to the '70's era stuff. it would have a pcv air filter tucked inside the engine air filter housing and held with a sheet metal C clip. attached to that with a short rubber hose would be a metal tube that pushes into the grommet in the (driver's side?) valve cover. on the other valve cover will be a pcv valve that pushs into a rubber grommet and is connected to engine vacuum. it is supposed to draw a metered amount of air from inside the engine through the pcv valve and if there are not enough fumes or blow by inside the engine then the fresh air supply from the air filter housing will supplement to keep up with the demand from the pcv valve. that way a fresh supply of air is readily available to purge fumes from the engine internals. sometimes, if too much blowby in the engine or the pcv valve gets plugged or the vacuum line gets compromised etc, the air filter will fill with oil because of back pressure/flow down the "clean air" line. a compression test and a cylinder leakdown test would be done after a check of the pcv system proves that system is not at fault.
also, check the viscosity of the engine oil. if it is diluted with fuel, which can happen after sitting for awhile or if there are carb issues, the oil will find it's way out of every crack and cranny. if it smells like fuel change it out before you start the engine again. oil pans and valve covers have been blown off from explosions inside the engine caused by fuel contaminated oil.

post up some pics of the engine and what it looks like before a wash, if possible. are the valve covers aftermarket? if so, most will have a knock out plug you can see from the backside for the pcv stuff. maybe the PO installed early covers for the stock look but that system used an oil filler tube in the front of ther intake manifold with a push on vented lid. the engine had a draft tube attached at the rear ( a lot were plugged by owners who upgraded the look to newer style) and the tube went down to the outside of the engine and ended around the level of the bottom of the oil pan. if you have old covers without holes and a new style intake without an oil filler/vent then there is no ventilation to speak of and it will push oil out where ever it finds a likely spot. maybe your problem?

04-06-2017, 05:37 PM	#11
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,501	Re: Inspected Condition `\ : - ( Truck without seeing a pic of the engine i assume it should be similar to the '70's era stuff. it would have a pcv air filter tucked inside the engine air filter housing and held with a sheet metal C clip. attached to that with a short rubber hose would be a metal tube that pushes into the grommet in the (driver's side?) valve cover. on the other valve cover will be a pcv valve that pushs into a rubber grommet and is connected to engine vacuum. it is supposed to draw a metered amount of air from inside the engine through the pcv valve and if there are not enough fumes or blow by inside the engine then the fresh air supply from the air filter housing will supplement to keep up with the demand from the pcv valve. that way a fresh supply of air is readily available to purge fumes from the engine internals. sometimes, if too much blowby in the engine or the pcv valve gets plugged or the vacuum line gets compromised etc, the air filter will fill with oil because of back pressure/flow down the "clean air" line. a compression test and a cylinder leakdown test would be done after a check of the pcv system proves that system is not at fault. also, check the viscosity of the engine oil. if it is diluted with fuel, which can happen after sitting for awhile or if there are carb issues, the oil will find it's way out of every crack and cranny. if it smells like fuel change it out before you start the engine again. oil pans and valve covers have been blown off from explosions inside the engine caused by fuel contaminated oil. post up some pics of the engine and what it looks like before a wash, if possible. are the valve covers aftermarket? if so, most will have a knock out plug you can see from the backside for the pcv stuff. maybe the PO installed early covers for the stock look but that system used an oil filler tube in the front of ther intake manifold with a push on vented lid. the engine had a draft tube attached at the rear ( a lot were plugged by owners who upgraded the look to newer style) and the tube went down to the outside of the engine and ended around the level of the bottom of the oil pan. if you have old covers without holes and a new style intake without an oil filler/vent then there is no ventilation to speak of and it will push oil out where ever it finds a likely spot. maybe your problem?