crankcase ventilation tubes

Plastic gallon jug with steel wool in it. Slobber tube goes in it's opening to the bottom and you add some extra holes at the top to vent.

Ivylog wrote:
Plastic gallon jug with steel wool in it. Slobber tube goes in it's opening to the bottom and you add some extra holes at the top to vent.

I'm curious. Why the steel wool, to keep the vented oil from sloshing?

If you do not over fill the crank case, you should not have any oil coming out the breather tube. The problem Cat had with their engines was that on the 3126-E and early C-7 engines originally instructions were that it took 24 quarts of oil. When the problem got real bad and oil was getting on some radiators a new revision was put out by Caterpillar that the engine required only 19 quarts of oil.
The problem was solved.

Mine come out of the factory with the slobber tube already extended all the way down to the top of the mud flap and I never had any oil coming out of the tube. But I did read and I wittnessed an AirStream coach that lots of oil sprayed all over the bottom of the engine. It was ugly and that is where I first saw the revision that that gentleman got directly from Caterpillar.

Not sure if they had the slobber tube problem with the Cat 3126-B which did have the deep oil pan and it took a lot more oil.

I also heard Cummins also had a slobber tube problem, but again not sure what their problem was.

The oil in the vapor needs something to cling to. Just slowing down the vapor will not let much of the oil settle out. The steel wool can be reused by washing it out in gasoline. I would use course steel wool and even some course scrub pads in the bottom. You could get carried away and do a tri level one... scrub pads in the bottom, course steel wool in the middle and fine steel wool in the top. A screw on lid gallon jug would make it easier to build and service... holes in lid for tube and vents.

If you have a lot of oil in the vent... getting the car dirty I would be concerned about the amount of blowby in the engine and what's wrong with it. If it's a 04 Cat C7 then a different vent system might be necessary as it had problems with excessive oil from the side vent.

Our previous coach with Cat C7 had the slobber tube. I just put an extension on the tube and ran it out past the radiator assembly. We've always had a toad, and even with the extension, I never found any oil residue on the front of the toad.

Ron

Yup, first step is to CALIBRATE the engine oil dipstick. It was NOT provided by your engine manufacturer. It may or may not be accurate.

IF you overfill, your engine WILL puke it out.

If you still have a problem after verifying that you are not overfilling the crankcase, indeed fit a catchment jug. Just make absolutely positive that you do not restrict air flow.

And if you are going to use something such as the steel wool recommended (a reasonable concept), use something that will not rust. So bronze wool (marine store) or stainless steel. Regular steel wool when exposed to the moisture it will be exposed to in that location, will turn into a pile of rust and if left long enough will restrict air flow.

Sure, if you live and drive in the desert SW, not a problem.

wolfe10 wrote:
Yup, first step is to CALIBRATE the engine oil dipstick. It was NOT provided by your engine manufacturer. It may or may not be accurate.

IF you overfill, your engine WILL puke it out.

If you still have a problem after verifying that you are not overfilling the crankcase, indeed fit a catchment jug. Just make absolutely positive that you do not restrict air flow.

And if you are going to use something such as the steel wool recommended (a reasonable concept), use something that will not rust. So bronze wool (marine store) or stainless steel. Regular steel wool when exposed to the moisture it will be exposed to in that location, will turn into a pile of rust and if left long enough will restrict air flow.

Sure, if you live and drive in the desert SW, not a problem.

In doing a search with regard to Crankcase Ventilation Tubes (a.k.a. Slobber Tubes) I've read of several references to these catchment containers. Wondering if anyone who has done this might have photos of your installs and retrofits? I'm somewhat interested in possibly putting one on mine, but can't figure out where in the world I would mount it? Looking for ideas on how others may have done it.

Here's my version.



Start with a trip to the Dollar store and get a spray bottle, remove spray unit.
Drill some holes at the sholder area of the bottle.
Attach a length of wire to the neck of the bottle using a zip tie around the neck as a anchor.
You will probably have to cut the opening out a bit bigger to fit over the slobber tube.
Place the unit over the tube and wire it / hang it to any convenient point that will allow the bottle to hang freely at the end of the slobber tube.
Insert the slobber tube into the bottle but be sure to not have the tube end below the drilled holes so that no back pressure can be created.
In 2000-3000 miles I have seen only about 1/4 inch of acccumulated oil, so emptying and cleaning is something that I plan on very infrequently.

John's concept if fine, but I would have a LOT more exhaust holes. I did not buy a bottle, dumpster dove for a "like new" Gatorade bottle. Took an old punch and torch and melted 12 holes slightly over 1/4" around the top. Ran nylon cord through two of them and zip tied it in place.

I always recommend that the sum of the exhaust holes well exceed the size of the original hose (1" ID for the OP). Go back to area of a circle= pi R squared.

And make sure that the hose does not go all the way to the bottom of the bottle, as that will restrict flow as well.

Great! That's the type of info I was looking for. Thanks guys!

Actually, I made a test bottle up and tested it this weekend. I used a large, wide mouth vitamin bottle. The wide, childproof cap worked well. I stuffed some Bronze Wool in the bottom. Took it for a test run for about an hour drive. Of course, no oil came out of the slobber tube, but the assembly stayed together. I will eventually use a larger receptacle.

I also had to extend the length of my slobber tube by adding some 3/4 id x 1" od vinyl tubing. That worked perfect. There was an unused threaded hole in the side of the engine block right inline with the slobber tube that I used to bolt on a 1" rubber coated hose clamp and ran the vinyl tube through it. This elimiated any pull-down stress on the slobber tube. That will help when I add a larger receptacle. The vinyl tube fit perfectly over the end of the original slobber tube and I added a 1" hose clamp to hold it together.

When drilling the "breather holes" in my bottle, I drilled (6) 3/8" holes. This is more than 2x the opening area of the slobber tube. The slobber tube coming off of the engine on mine is 9/16" (.5625)ID x 1/8" wall. My vinyl tube extension is 3/4" ID, which is why it fit over the original tube nicely. (However, I'd like to know where Cummins found 9/16" ID tubing?? Why not standard 1/2" or 3/4"??)

The reason for getting into this mod was because the original slobber tube only came down along the side of the engine block only about 2/3 of the way. I was getting tired of cleaning the oil/gunk off of the side of the engine. Not only that, as the gunk would build up, the oil would evenually spot the driveway when it would stop "sticking" to the engine.

I will try to post some pics of my fix when I get the final receptacle made up and attached.