What bad things can happen from haveing a open crankcase ventilation system?
 

May has been an unlucky Month for me. Especially this May. One of the things that happened is I did an Oil Change and when I put 5 quarts of new Oil it did not go into the Engine but down on my Driveway.

Unseen was the fact that the Oil Fill Pipe had pulled out entirely from the Valve Cover Grommet leaving a open hole and no way for the new oil to get into the Engine.

Since for over 6 Months I had occasionally been smelling Oil Vapor I had been driving with that Oil Fill Pipe disconnected.

Next is I had to have a smog/emission tests and despite the fact that I passed last year after installing a new Catalytic Converter. I failed with high HC and CO emissions.

Now I am wondering what 6+ Months of driving with the Oil Fill Pipe disconnected messed with concerning the positive crankcase pressure and what effect that would have? Which is my question to you all.

I don't see anything it would harm but then you don't say what car it is so if its newer it might.

My tractor has an open vent-it's been fine since the 60's

Vented crankcases to atmosphere where standard for decades. Actually better is claimed as less acid accumulation occurred. The change was one of the earliest components of reducing pollution.

As mentioned already. I too cannot see it impacting your pollution test. A working mechanic might give a better answer on your thread.
The exception being It might upset the mass air sensor. That is beyond my knowledge limits. Unless you look at the crankcase ventilation system as a closed loop.

Usually as I remember. The manufactures ran a tube down towards the road. Hence the name road tube was heard frequently. Another approach was the oil filler cap had holes in it. Plus some heavy steel wool inside it basically. The oil cap was actually more of a small vented container.

Oil changes where recommended at 1000 miles and some perhaps at 1500 miles. Even after cars got oil filters. Also greasing all the chassis points at the same time was normal.

Fair enough it is a 1992 Chevy Astro Van with a 4.3L vin W Engine and it has an electronically controlled EGR.

PCV system is supposed to be a closed system. There is a PCV Valve connected to a vacuum source up near the throttle butterfly. I cannot remember if the butterfly valve crosses over the vacuum port or not.
Specifically what I am trying to determine is how the PCV Valve would act in the face of the engine side being opened to the atmosphere.

I an speculating that if the PCV valve would remain open that would allow the Intake Manifold Vacuum to fall and that from that the computer would interpret that you were trying tying to accelerate and give you more fuel. Which would be why I was getting more fuel (hight HC) resuliting in the high CO.

Fault codes 22- Low TPS Voltage, 42- Electronic spark timing ECM/PCM open or grounded circuit and finally 44- O2 Sensor lean.

So on Code 44 carbon covering the O2 sensor could cause it to show lean. I have not pulled that yet.

After checking the fault codes I shut it off and disconnected and reconnected the electrical connectors going to the distributor and when I tried to restart it cranked but would not start.

I found that the ECM1 fuse was shot. Replaced it and it started.
Today’s plan is to drive it a bit see if the check engine light still comes on intermittently and hope it does not die on me and see if any of the codes clear.

Before I sat down on the computer I cleaned up the kitty litter I poured on the 5 quart oil spill in the drive way so I can get under the Van and see if the O2 sensor is carboned up or not and see if any of the wires got burned as there is a section of the wiring loom near the exhaust pipe.

Before the Smog Test I had replace the Destributor Cap and today I found that one of the spark wire connections was not snapped down firmly. I also rechecked the firing order.

Note that an Oil change is recommended before you do an emissions test because of the accumulation of unburnt fuel in old Oil. So I had previousl changed the Oil.

My 1953 chevy pickup truck has the vented cap on the valve cover and the draft tube you are speaking of as did my first car a 1954 caddilac.

Would not cause any damage to engine.

I was thinking on a modern engine it might futz the computer.

I was not entering that it would damage the engine. But a rich mixture could clog your O2 Sensor and the Catalytic Covert with carbon.

I cleared the fault codes and took it for a 40 minute drive now there is only code 22 showing and that was the Throttle Position Sensor. Note I have had that intermittent code for about 6 years and it had always passed the emission test. I had also replaced the Throttle Position Sensor 3 times with no fix.

Will need to drive longer to see if the other fault codes return.

I used to have a CO tester. But, it got broke many years ago. Without that I have no idea of what I do effects a good change.

I failed the first emission test the next test is free but there is a $9 fee for the certificate if I pass.
If I don't pass I start over and pay again.

Note out here the DMV ordered me to go to a station that does not offer repair or diagnostics to determine what the problem really is. I go there anyway because I don't want the Mechanics hassling me to let them fix it and of course pay for the fix.

Here is a pic of what I found after I saw the pool of Oil on the ground and I remved the "dog house" so I could get a good view of the Oil Fill Pipe end.

I have no idea how it got pulled out like that.

Well, that doesn't look good.

Could you have produced enough blow-by to unseat the pipe?

No. No blow-by comes out when I remove the Oil Fill Cap and since I stuck it back inside it has not popped out by itself.

Also when I stuck it in there years ago I used silicon sealant which should have glued it in.

Several times when I left the Dog House off overnight I have had one of the local Tom Cats squeeze through the Engine Compartment (the same cat every time) and found him lounging on one of the Seats in the Van. I suppose it is possible the Cat trying to get inside could have pushed the tube out.

I have also left the hood open and taken a nap. It is possible some malicious person grabbed the Oil Fill Tube and pushed down on it. But, I think the Cat is more likely the one that did it.

I think it would take something like a head gasket leak to push the tube out.

The PCV is probably on the opposite valve cover. All that would happen with this doohicky being disconnected is that air would flow through the oil fill hole, through the engine, and into the PCV, which is pretty much what normally happens. The PCV valve will prevent the manifold vacuum from becoming depleted, regardless of whether the crankcase is open or closed.



If a lot of oil splashed out of that hole, you may have been running the engine low on oil. Dirt could have gotten in here, but would probably be cleansed through the oil filter. Other than that, there's no way this would cause long term harm. Your emissions problem is something else. Possibly the PCV valve itself is defective, and that's why your fill hose blew off. I'd start by replacing the valve.