PCV problem? Oil leak

[46stude]

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.

[46stude]

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.

[demian5]

Originally Posted by 46stude

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.

[46stude]

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

[46stude]

Update: I did cause the problem.

When I first put the truck together, every so often while running down the hiway, the PCV would pop out of the valve cover. I knew when it happened because the oil smell would come into the truck. So I'd pull over & pop it back in. I believe this was the direct result of not properly plumbing the engine for the PCV. I had no breather on the opposite valve cover for the PCV to circulate air into the 350.

Apparently, at some point the hose must have layed on the exhaust manifold long enuff to partially melt it. So the hose was sucking air, which is also probably when the PCV magically stopped popping out.

So, when I noticed the hose was bad & I replaced it, the PCV had, over time, locked itself into the grommet. Instead of being able to pop itself out of the valve cover, the PCV instead popped the intake seal at the back of the engine, resulting in the oil leak. And it apparently only leaked while under load & actually running down the road. You'd think the oil leak's location would be obvious, but it wasn't.

So, I yanked the intake a couple days ago & replaced the gaskets & RTV on the china walls. There was an "extra" grommet I'd plugged, so I bought a grommet & breather at O'Reillys & put them into the drivers side valve cover.

I put 40+ miles on the truck yesterday, & no oil leak. Problem solved..... I think.

[46stude]

Pics for anybody running factory TBI style center bolt valve covers like mine:

[rocknss]

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.