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Joined: Oct 1999
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I have a 76 F350 supercab, camper special with 460/C6 and 66K miles. Truck runs great has lots of torque, but after 40-50 highway miles it begins to blow oil out the dip-stick tube. PCV is new and connected to correct vacuum source on the 600CFM Holley. Crankcase breather is also new and connected to the aircleaner. What could be causing the pan to pressurize and blow out the oil. I have noticed that once I get about a qt. low (oil capacity for this engine is 6 qts.) there's very little if any blow-by. Engine doesn't smoke; idles very smoothly at 650 RPM, and has never performed better. Anyone care to diagnose/suggest a fix? All advice will be appreciated.
Thanks,
JohnnyJ in NVA
Thanks,
JohnnyJ in NVA
Senior User
Joined: Jun 1999
Posts: 222
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I hate to say this but your PCV system is not working. You have a slight leakage of compression past the rings and into the crankcase which is perfectly normal. But the PCV should be pulling that pressure back into the engine to be burned up. Start with the easy things and rod out all of the hoses to make sure they are clean and clear. I know they are new, but double check the valve and intake breather. The PCV is hooked to the carb? It works best connected to a PCV plate under the carb. Crankcase fumes aren't exactly clean and will eventually crud up your carb throttle plates. Finally, pull the valve covers and make sure the oil return passages to the crankcase are clear. Somewhere, someplace the vacuum part of the system is clogged.
Elder User
Joined: Oct 1999
Posts: 917
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From: Kelseyville USA
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Just a thought.. On my Fe:390 I blew the intake manifold gaskets for the Exhaust Cross Over passage. It was fine Cold but what a problem after it got hot.Lots more than the PVC valve could handle and clean oil comming out the dip stick tube!!
May be something to look at....
__JOHN__Õ¿ö
72 F-250
May be something to look at....
__JOHN__Õ¿ö
72 F-250
