Oil leaking from PCV - '94 Chev K1500 5.7L

[LSUfan71]

I'm apparently having a problem with increased pressure in the crankcase. I need some help/suggestions diagnosing the problem.

The breather hose from the throttle body to the driver side valve cover had been brittle and had cracked, I used some foil tape for a temporary fix. Last week I was adding oil and I accidentally bumped the hose, breaking it off just above the valve cover. For another temporary fix I covered the broken end with plastic/cable tie and plugged the opening at the back of the throttle body. I drove the truck once and I had oil leaking from the PCV on the passenger side valve cover and from the grommet at the breather hose on the driver side valve cover.

I couldn't find an OE breather hose so I found vacuum hose with the same OD and inserted it into the breather opening at the driver side valve cover. The other end fit nicely onto the same opening on the rear of the throttle body. I also replaced the PCV. Since then I've had oil leaking through the new PCV twice. Seems to be getting worse. This is in addition to the slow leak I've had from the rear of the engine (which I've presumed to be the rear main, planning to get fixed).

My question is: Have a I possible damaged the engine by plugging off the breather hose? Suggestions or hints? I'm not a professional mechanic but I can get things done if I can get help with diagnosis.

 

[95Escahoe]

You need the hose that goes from the front of the TBI to the PCV valve? If so Advance sells it

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[lha1992]

So did you plug the hole in the drivers side valve cover or did you leave it open?

Alot of guys now including myself delete the hose from the drivers side valve cover to the to the TBI air filter riser because I've heard some guys say that that can cause the TBI to gunk up with oil. Mine never did it only a lil bit of residue was on the TBI but I went ahead welded up the hole in the riser an put one of those push in chrome breathers in place of the re-breather hose an got a new pcv valve to boot from the dealer cuz ive had bad rattle with ones from the auto stores.

You need the PCV valve in the passenger side valve cover. In essence what this does is the engine pulls bad contaminated air from the passenger side of the engine an sucking in clean air from the drivers side breather.

Now I have to ask how many miles do you have on your engine??? Because as your engine gets older your piston rings become old an worn out those you get blow by getting burned off an as the pistons go down an back up to TDC (top dead center) it will create a vacuum thus pushing the oil either into the combustion chamber or outta the engine an in this case your PCV due to your engine sucking all that bad air in to be burned off.

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[great white]

Get some oil rated hose on the pcv. Vacuum tubing will swell and close off in oil as it is not rated to handle oil.

If that has happened and you have the other valve cover blocked off, the only way for crankscase pressure to escape is around things like the dipstip tube and oil filler cap. This can case excessive crankcase pressure and some of the things you are seeing...

 

[LSUfan71]

I'm an idiot. The last thing I checked should have been the first thing. I had assumed there was vacuum on the PCV line. Well I finally checked it and there was none. I pulled the line and the port was plugged with gunk. I had to pull the TBI off the intake to get it cleaned out. I put it back with a new gasket and it's running much better, seems to be improving actually. Good vacuum, no sign of burning oil. Blowback doesn't seem to be a problem at all. I've got a horrible oil leak but that's for another thread.

You need the hose that goes from the front of the TBI to the PCV valve?

No, I needed the one that goes from the back of the TBI to the driver's side valve cover. But I used fuel line with the same OD as the opening. Seems to be working fine.

So did you plug the hole in the drivers side valve cover or did you leave it open?

Alot of guys now including myself delete the hose from the drivers side valve cover to the to the TBI air filter riser because I've heard some guys say that that can cause the TBI to gunk up with oil. Mine never did it only a lil bit of residue was on the TBI but I went ahead welded up the hole in the riser an put one of those push in chrome breathers in place of the re-breather hose an got a new pcv valve to boot from the dealer cuz ive had bad rattle with ones from the auto stores.

You need the PCV valve in the passenger side valve cover. In essence what this does is the engine pulls bad contaminated air from the passenger side of the engine an sucking in clean air from the drivers side breather.

Now I have to ask how many miles do you have on your engine??? Because as your engine gets older your piston rings become old an worn out those you get blow by getting burned off an as the pistons go down an back up to TDC (top dead center) it will create a vacuum thus pushing the oil either into the combustion chamber or outta the engine an in this case your PCV due to your engine sucking all that bad air in to be burned off.

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I used fuel line as a replacement to the driver's side valve cover. It's doing fine. I might do a breather later. The truck has 184,000 miles but the engine seems to be really strong. Thanks for the replies but I made a huge mistake by not checking vacuum first.

Get some oil rated hose on the pcv. Vacuum tubing will swell and close off in oil as it is not rated to handle oil.

If that has happened and you have the other valve cover blocked off, the only way for crankscase pressure to escape is around things like the dipstip tube and oil filler cap. This can case excessive crankcase pressure and some of the things you are seeing...

Yea, that's what I did. Can't believe I didn't check the port first though, just made an erroneous assumption. Thanks for the reply.

 

[Mike Murray]

I'm having the same issue. I'm noticing oil coming out of the oil fill cap, and the pcv valve on the passengers side as well as the hose on the drivers side. I removed the lines and placed breather filters on them, and replaced the oil fill cap. No more oil leaks but it also bogs down and dies when I drive in the rain. I have replaced spark plugs, plug wires, and cap and rotor. Its getting spark but I'm wondering if a vacuum line is getting moisture in it?

 

[Schurkey]

I'm noticing oil coming out of the oil fill cap, and the pcv valve on the passengers side as well as the hose on the drivers side.

Symptoms of excessive blow-by, or a failure in the PCV system, such as a defective PCV valve, a plugged vacuum port, or a degraded PCV hose.

I removed the lines and placed breather filters on them,

That's a mistake. You haven't fixed the cause of the problem.

but it also bogs down and dies when I drive in the rain. I have replaced spark plugs, plug wires, and cap and rotor. Its getting spark but I'm wondering if a vacuum line is getting moisture in it?

Spray the ignition system with a spray-bottle of water, while the engine is running good.

Start with the spark-plug area (both sides, every spark plug), move on to the spark plug wires--spray along their entire length. Spray the top of the distributor cap, then the coil wire, then the coil.

When the engine starts to misfire, you've found the problem.