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Old 04-20-2017, 09:22 PM   #1
46stude
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PCV problem? Oil leak

I've got a '93 350 in my Cheyenne, pretty well stock innards w/ a real mild cam. It's got a Q Jet on an aftermarket intake, 1" spacer under the carb.

A week or so back I noticed the PCV hose had rubbed a raw spot & was sucking air, so I poppped on a fresh hose. This truck is a POS & it's sat way more than it's been driven, so I don't know how long the bad spot had been in the old hose. Not more than 1000 miles, I can say, though. Doubt I have 1500 miles on the truck since I put the stupid thing together.

I now have oil leaking off the back somewhere, enuff to coat the underside of the truck during a 70 mile trip today. It'd never leaked oil before. I've been all under the truck & on top of it, but nothing is glaringly obvious as to the source.

I keep coming back to the PCV hose, though. I've attached a pic of my set up. Does this need a breather on the drivers side valve cover? I just feel like the oil is something I caused when I put on the new hose.
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Old 04-20-2017, 09:45 PM   #2
firedemon
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Re: PCV problem? Oil leak

I doubt you caused a oil leak by putting the hose back together but it should have a breather or it will cause an oil leak most times the pressure pushes out valve covers or the back of the intake
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Old 04-21-2017, 12:19 AM   #3
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Re: PCV problem? Oil leak

This is how I have mine setup. I have the PVC on the passenger side going to the Carb and a Breather on the driver side circled in red.
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Old 04-21-2017, 11:03 AM   #4
46stude
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Re: PCV problem? Oil leak

Thanks for the comments, guys.

Yeah, that's what I'm about to do. My mistake came in NOT having a breather on the drivers side, methinks. With the bad hose, the PCV wasn't working correctly. With the new hose, I think I pressurized the engine & blew out part of the rear intake seal because the PCV was working & had no source to draw in air.

Sucks because I was gonna take it on a road trip this weekend to a car show in Texas City. Don't have time to pull the intake & fix the oil leak, though, so the truck'll just sit at home instead.

Moral of the story- a properly plumbed PCV system needs a breather, or you're gonna have problems. Just one of those things I overlooked.
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Old 04-21-2017, 11:32 AM   #5
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Re: PCV problem? Oil leak

Quote:
Originally Posted by 46stude View Post
I think I pressurized the engine & blew out part of the rear intake seal because the PCV was working & had no source to draw in air.
If PCV hose is connected to manifold vacuum on the intake manifold or base of carb (as it should), that creates a vacuum (negative pressure).

This would cause the opposite of oil leaks, it could possibly smoke from sucking oil from the crankcase through the PCV and into the intake.

So, you could have "sucked " the seal into the lifter valley. That would make sense.
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Old 04-21-2017, 11:48 AM   #6
46stude
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Re: PCV problem? Oil leak

I believe that's what I'm dealing with. "Blowing" out the intake seal was the wrong description. I think.
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