Started the boat in the pen today. After start I immediately checked for water flow from the exhaust as I normally do, and noticed that for the first 10 seconds it was a milky color. After this time in ran clear. Boat had not been used for about 2 weeks and engine oil, gearbox oil and coolant levels were last checked a few days ago and were normal. Any ideas?
Milky exhaust water. Cummins 6bta
- Thread starter caltexvb
- Start date
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twistedtree
Guru
Maybe just air? If really mixed in it can appear milky? I think the key is to keep a lookout for oil that’s going missing. And maybe scoop up a sample of the exhaust in a bucket and let it settle out to see what you have?
Thanks for the reply. Yes collecting a sample of the exhaust water was next on our list. Oil quantity stable so hopefully was just finely dissolved air. May have been worth mentioning the coolers were recently removed and cleaned but the engine would have about 5 hours additional running time on them since then so wouldn’t think related.
twistedtree
Guru
I had similar discharge from my generator and was concerned too until I finally concluded it was just entrained air.
Ski in NC
Technical Guru
As the zincs do their things as corroding anodes, that forms crud that goes out with the next start. I see this on many engines, including my own 6CTA. I call it normal unless there is some other indication of trouble.
Probably air or zinc oxide in the water as noted above. Next time you start look for an oil sheen surrounding the exhaust. If you have any significant oil or diesel in your exhaust it will show up as a sheen. But if you are not losing oil, that is unlikely and diesel doesn't look milky if it is present.
David
David
