Oil Catch can and condensation

[Larryjb]

This year my oil catch can is collecting so much water I'm emptying it once a week. My coolant level isn't dropping, so it's got to be condensation. Anyone else collecting heaps of condensation like me?

 

[gooffeyguy]

You make a lot of short trips?

Usually a motor will produce condensation inside the crankcase shortly after starting up from being cool. After it gets up to operating temp it takes a little while for that condensation to burn off.

If you only drive it a couple miles then shut it off and it cools back down before driving it again for a couple miles you will see more water, or the oil in the catch can will look milky.

 

[Larryjb]

I'm more than just a few miles, it's a good 25 minute drive each way to work and back.

I have read that some catch cans are poorly insulated which causes significant condensation inside the can itself. I didn't get as much condensation last year, but perhaps it's been more humid here this fall.

 

[Joseph Garcia]

I'm no oil catch can expert by any means, but I would not expect to see (nor do I see in my oil catch can) large amounts of water.

 

[Larryjb]

I've been reading elsewhere that some catch cans that have thin walls produce a lot of condensation inside that doesn't get evaporated out with normal driving. I'll admit I got a cheap catch can, and this may be the result.

I didn't seem to get this much condensation last year. I'm going to assume it's a result of more moisture in the air and cooler temperatures now.

 

[SnowDrifter]

'Bout par for the course for cold weather. Just drain it more often and don't think much about it.

There are some pros/cons to mounting locations on the catch can.

Mount it somewhere cool (but not where it would freeze): You'll catch more schmoo, water included.

Mount it somewhere warm: Will catch mainly oil particulate, but less water / other VOCs,

I have mine mounted somewhere on the cooler side and just drain it more often, personally. It's on driver's side cowl, next to the master cylinder. It won't freeze if it's cold, but that's about it. The way I see it: Anything that ends up in there, is more junk not recirculating to the intake.

 

[Larryjb]

I'm having to drain it every day now.

If I don't keep it drained, I get a tapping sound on start up that doesn't go away. If I drain it, the tapping sound goes away within the first few minutes of driving. I have ready elsewhere that the PCV valves can make noise too which would make sense. If the catch can is full of water, the vacuum won't be strong enough to open the PCV valve properly, and the ball valve inside the PCV may rattle.

However, I'm concerned it's more than that. The tapping sound is very regular indicating a lifter may be getting sluggish. I can't think of anything else that could be making such a noise that is related to the PCV not scavenging oil vapours properly.

Given all this, I may be better off deleting my catch can if I am unable to keep it drained.

 

[Joseph Garcia]

I'm having to drain it every day now.

If I don't keep it drained, I get a tapping sound on start up that doesn't go away. If I drain it, the tapping sound goes away within the first few minutes of driving. I have ready elsewhere that the PCV valves can make noise too which would make sense. If the catch can is full of water, the vacuum won't be strong enough to open the PCV valve properly, and the ball valve inside the PCV may rattle.

However, I'm concerned it's more than that. The tapping sound is very regular indicating a lifter may be getting sluggish. I can't think of anything else that could be making such a noise that is related to the PCV not scavenging oil vapours properly.

Given all this, I may be better off deleting my catch can if I am unable to keep it drained.

Have you checked your PCV valve for proper operation?

 

[Larryjb]

@Joseph Garcia You're right Joseph, I'll have to check that too. That may be a reason why the water never gets evaporated while driving either.

Anyone ever heard of bad PCV's wrecking lifteers? I sure hope not. Those would be a real PIA to change.

 

[Larryjb]

Just to update:
I have been emptying the catch can every day and the lifter tapping is much better. I get about a tablespoon of condensation every day at the moment. This was an inexpensive catch can and it won't hold much before it fills up.