Oil Catch Can - is it needed?

[Willys2Gladiator]

If you take an average of like 1.5 ounces of oil per 1000 miles that the can catches. Then an average of 18 miles per gallon, which is 55 gallons of fuel over 1000 miles. You're talking about burning roughly 0.00021094 oz of oil per 1 oz of gas. Or roughly 37 gallons of gas for every one 1 ounce of oil.

That oil is not going to do any harm to your engine. Ever.

Agree it's not going to harm anything. But why have it go in at all. Just personal preference I guess.

Sponsored

 

[Gladman]

You used good quality hoses, right? Cheap stuff will be swollen and will rot from the oil mist.
Clean looking install.

Very true, use silicone hosing wherever possible.

 

[Trlr8tdd]

My 150K mile JK upper manifold looked Horrible when I pulled it for plugs and packs at 110K, cleaned the upper. Then I replaced the oil cooler at 150k, the lower was 10x as bad as the upper, I cleaned the crap out and replaced the PCV valve. I’m putting catch cans in my JK and JT. The cleaner I can keep the manifold the happier I am. It is of course normal.

 

[Mac]

Update from my install several months ago, less than 5k miles. Maybe I need a bigger one.

 

[Willys2Gladiator]

Update from my install several months ago, less than 5k miles. Maybe I need a bigger one.

Yeah. And do you want that going into your Jeep! I also chose not!!!
Crazy. And some say it's just water from condensation but if that was the case it would separate but it doesn't. Maybe some but a lot of oil.

 

[one2doo]

Mine did the same.

 

[KurtP]

Imo everyone should run a catch can on these motors, especially if youre running 87.

If for no other reason than knock suppression. But run one.

 

[Mac]

Another update, towing around 3500lbs a lot this summer, catch can was about 3/4 full after 2k miles, pure oil in the warmer months also no moisture like it had when it was colder.

 

[Fastwake]

Catch can ARE YOU SERIOUS

 

[ShadowsPapa]

Another update, towing around 3500lbs a lot this summer, catch can was about 3/4 full after 2k miles, pure oil in the warmer months also no moisture like it had when it was colder.

Pure oil - so you are saying that the contents of the catch can are exactly the same color as what's in the pan and the same texture or feel........ it has no tan color, and doesn't look like the example in a prior post where I could prove only some of that is actually oil........

And you are saying your engine is low by that much that's in the catch can - it's visibly lower on the stick....
For every pint on the catch can, for it to be oil, you must be 1/2 quart low on the stick.

Interesting - I could go out to mine now that it's sat 24 hours and check the stick and it will be right at the full line. There's 1 quart between full and low. half-way between would be a pint.
There are 4 cups (32 ounces) in a quart. So if that catch can holds 8 ounces, or 1 cup, you should see a drop on the stick of about 1/4 down from full to low.

 

[Mac]

Pure oil - so you are saying that the contents of the catch can are exactly the same color as what's in the pan and the same texture or feel........ it has no tan color, and doesn't look like the example in a prior post where I could prove only some of that is actually oil........

And you are saying your engine is low by that much that's in the catch can - it's visibly lower on the stick....
For every pint on the catch can, for it to be oil, you must be 1/2 quart low on the stick.

Interesting - I could go out to mine now that it's sat 24 hours and check the stick and it will be right at the full line. There's 1 quart between full and low. half-way between would be a pint.
There are 4 cups (32 ounces) in a quart. So if that catch can holds 8 ounces, or 1 cup, you should see a drop on the stick of about 1/4 down from full to low.

Looks like pure oil, could have some fuel in it I suppose, color and lubricity feel like the same stuff in the pan. I do not pay that much attention to the oil level to know if it is down a half quart, as long as it is near the middle area I am good.
I know catch cans are not really needed on these motors but it is interesting to see what gets caught in it.

 

[ShadowsPapa]

Looks like pure oil, could have some fuel in it I suppose, color and lubricity feel like the same stuff in the pan. I do not pay that much attention to the oil level to know if it is down a half quart, as long as it is near the middle area I am good.
I know catch cans are not really needed on these motors but it is interesting to see what gets caught in it.

I'm not interested in buying one - but it would be interesting to "borrow" one and run some tests just to see - I can separate the oil from any water, run some other tests and checks and see what actually IS in there. So many pictures I see remind me of what comes out of a pan after a minor coolant leak - or what came out of my 73's oil pan after a heavy rain dumped water into the crankcase via the exposed carburetors (sticking up through the hood) one picture looks exactly like what came out of that engine, including the white teeny tiny foam around the edge (which indicates strong water content)
I'd love to do some real testing, scientifically, actually measuring, etc.
When mixed by a running engine and enough turbulence, water will stay suspended in the oil.

For those saying "it's not water, water separates out" - uh, no. And even what may will take TIME. Engine oil will hold water - yes, HOLD it. It only settles out when the oil has reached a certain point, and time. Saturation point..........
Once the saturation point is exceeded, water is typically present in the emulsified phase creating a milkiness or fog in the oil, just like moist air on a cool day.
That's what I see in a lot of the catch can photos I've seen - not oil, but an emulsion, a mix of oil and water. Only a part of that tan/dark tan is oil.
When sufficient water exists, or when the oil has adequate demulsibility, free water will collect. Because water is typically heavier than oil, it settles below the oil.

When oil contains the maximum amount of dissolved water it is said to have reached the saturation point. The saturation point is dependent on the oil’s temperature, age and additive composition.
The higher the temperature, the higher the saturation point and hence more water held in solution, in the dissolved phase.

Some science I found -
This is the same as being able to dissolve more sugar in hot water, than in cold water. Similarly, the older the oil, the higher the level of water that can be dissolved. This is due to polar by-products of oxidation in the oil, which act as “hooks” holding on to the water molecules and keeping them in solution. Likewise, highly additized oils, like crankcase oils, have a higher saturation point than lightly additized oils like turbine oils, because the additives - many of which are polar - also hold the water in solution.

 

[Pointman_nh]

I installed the JLT 3.0 (3 ounce) can in mine about 2k miles ago. Emptied it today. It was full to the top. I installed it because one day out doing some steep climbing, I got stuck in some mud and the exhaust started smoking. After seeing 3 ounces of oil in only 2k of miles, glad I installed it. I do most steep crawling in my area.

 

[foo.c]

I installed the JLT 3.0 (3 ounce) can in mine about 2k miles ago. Emptied it today. It was full to the top. I installed it because one day out doing some steep climbing, I got stuck in some mud and the exhaust started smoking. After seeing 3 ounces of oil in only 2k of miles, glad I installed it. I do most steep crawling in my area.

Does it still smoke?

I've seen this before and it was oil building up in the top of the cylinder head. There are holes in the head to drain back into the crankcase and at some angles a lot of oil can get caught without a way to drain out. The PCV then sucks up the oil that's trapped.

It seems like it could still pool up and get sucked in and overwhelm a small catch can.

Just curious.

 

[Casique]

Since you are modifying the PCV system, are there any warranty implications? I would like to install one, but not if the Jeep dealer is going to have an issue with it.

Sponsored