Mysterious Oil clouds.

[william curry]

Yesterday I started my Pinz which had been sitting for about a week.

The temp was 5 F.

It started right up and after a minute of full choke I reduced the choke to about 1/3 and went back inside so as to let the engine warm up.

About 15 minutes later I went outside and found that the motor had stopped.

I got back in and started it up again.

Upon the restart there was a huge cloud of oil exhaust from the exhaust pipe.

After a few minutes the exhaust cleared up.

I then noticed two blobs of oil on the ground, and then got under the unit and looked for the source of the oil blobs.

The oil blobs came from the engine exhaust connections to the heat exchanger.

I looks to me as though the motor somehow leaked a significant amount of oil into the exhaust system.

Why did this happen?

Do I have a serious problem here?

What should I do?

[Jimm391730]

In cold weather the oil breather tube can clog up, this can allow oil to be sucked into the engine. Check for the "white gunk" buildup on the inside of the oil fill tube and inside the breather tube. Usually that is all the problem is.

It helps to run the truck for long enough (hours, maybe) to get everything up to temp and draw off the condensation to help reduce the clogging. Short trips in cold weather make the problem worse.

Jim M.
712W and 710M

[cronapress]

I experienced this last winter. Low mileage engine in good nick, very little oil consumption. In between monthly trips to a mountain bothy, only do short mileage "local" trips. Just happened to glance out of mirror to see a bonzoid cloud of oil smoke! Pulled up on the verge smartish. Revved the guts out of it for a few seconds and all cleared again.

When I got home I checked the breather tube and found lots of creamy gunge. Pulled off the oil filler pipe and breather tube and gave them a good pull through with a piece of wire and cloth.

I think, as others far more knowledgeable than I have prev. said, a few long, hard runs will help reduce this problem. ie. get the engine HOT HOT HOT for while.

Oh for the long, hot summers you guys on the other side of the pond have! What's that about the grass is always greener ..blah. blah. blah...


Mike.
710M (Civ.)
Ayrshire.
Scotland.

[william curry]

Dear Jimmm.

I have a problem following your logic.

The oil breather hose located at the top of the oil filler tube vents into the air intake system. The intake system is operating at negative pressure so the positive pressure in the crankcase will vent into the induction system.

Therefore if the breather hose becomes obstructed how can it then feed oil from the engine into the intake system?

It doesn't make sense to me.

I am mystified.

[Jimm391730]

Therefore if the breather hose becomes obstructed how can it then feed oil from the engine into the intake system?

It doesn't make sense to me.

There is a second breather hose from the top of cylinder #4 that goes to the oil filler tube too, just lower down. Oil and vapors from this hose and the crankcase travel up the filler tube and condenses in it and the top breather hose when the weather is cold (and there is probably more blow-by from the pistons and rings when the engine is cold trying to get through this hose, too). When the top vent hose gets plugged from the white gunk then the pressure from the crankcase forces oil and/or white gunk (emulsified oil and water condensation) that is plugging it into the air horn above the carbs, giving a good douse of oil and junk into the carb(s), creating the oil exhaust. You can probably feel the remains of the gunk that created the oil exhaust if you wipe your finger inside the air horn near where the breather hose enters, probably dumping most of it into the front carb.

Hope this helps explain it.

Jim Mettler
712W and 710M

[dougj]

its pretty hard to get the pinz oil up to a decent temp, when the outside temp hovers in the 20's. so what I've been doing lately is just to pull the top cover on the doghouse, and remove the oil filler cap after I run the truck. (basically an escape path for the moisture) its a given that in order to do this, the vehicle must be garaged...but it helps.

[undysworld]

Doug, I had this problem here in Wisconsin too. It was really friggin cold out. In my case, what I'm pretty sure happened is that the air filter got some moisture on it and froze. I had oil in the air box above both carbs, just dripping all over. It had sucked over a quart of oil out of the engine within maybe 20 seconds! Dennis Williams suggested the problem and to remove the air filter. Worked fine. Cleaned it all up, replaced the filter and off I went. ???
It's only happened once, so that's my input FWIW.
Paul

[Charles]

Yup,
I second that last vote. Last winter I had that EXACT problem (only a bit worse) and it was, indeed a frosted over air-filter.

According to Dennis, what happens is that (in my case) frost tends to collect on the air filter (specially if you have the stock, metal lathe variety). When the engine cycles, this frost blocks the airflow and causes the engine to siphon up from the crank, causing the Pinz to puke oil (or crap oil if it's coming out the exhaust).

Really freaked the heck outta me , but per Dennis "these things are tough as old army boots", and once I got the oil pushed out, and the plugs cleaned up it continued to run like a champ.