catch can ?
Thread Starter
Pro
Joined: Dec 2001
Posts: 582
Likes: 72
From: Near Raleigh NC
catch can ?
I have a small catch can on my 2005 M6 (about 85k) and I do check it periodically maybe once a month or so. Most of the time oil is in it and is a normal dark color. Today I open it and find what looks like chocolate milk colored oil that is very runny. I see normal oil and color on dip stick and no apparent loss of coolant. Now I had installed this can back some time ago. Any thoughts? Starts, runs, no weird sounds, nothing out of place and leaks present. I normally don't drive it in the rain but did yesterday morning does this indicate a leak into my air intake?
Thanks in advance for any responses
Thanks in advance for any responses
Pro
Joined: Feb 2017
Posts: 610
Likes: 79
From: Fallbrook SanDiego county
So if you took in water it would only be in the catch can if it went through the intake manifold.> past the rings> into the oil> sucked into the catch can! I've never heard of this, but that doesn't mean it didn't happen though
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
The catch can is pulling crankcase fumes in from the valve covers and the valley cover ... no air is pulled directly into the catch can from the intake system.
Moisture can build up in the crankcase during high humidity days (especially just after startup). This moisture can change the color of the oil in the catch can to a chocolate milkshake color, while not effecting the color of the engine oil shown on the dipstick.
Bottom line ... don't worry about it, and there is no reason to do an engine oil change either (unless your due an oil change anyway)
Moisture can build up in the crankcase during high humidity days (especially just after startup). This moisture can change the color of the oil in the catch can to a chocolate milkshake color, while not effecting the color of the engine oil shown on the dipstick.
Bottom line ... don't worry about it, and there is no reason to do an engine oil change either (unless your due an oil change anyway)
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,150
From: SW Florida
2021 C6 of the Year Finalist - Modified
If you are worried about a small amount of water possibly entering the crankcase from the clean air inlet fitting on the large rubber hose in front of the throttle body, you can cap that fitting and install a filter/breather on the driver's side valve cover (oil fill cap).
This is for wet sump engines since dry sump engines are a completely different setup.
Dirty crankcase fumes will enter the catch can just from the valley cover fitting (valve cover fittings will be capped off too) ... see diagram below
Attachment 48332676
This is for wet sump engines since dry sump engines are a completely different setup.
Dirty crankcase fumes will enter the catch can just from the valley cover fitting (valve cover fittings will be capped off too) ... see diagram below
Attachment 48332676
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