Does this oil look bad to you? (white smoke coming out of breather tube)

platon20

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Jul 15, 2020
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Some very bad smelling white smoke started coming out of the ventilation tube that runs from the valve cover to the flame arrestor approx 10 mins after engine start. Engine temp climbs up to 180 before I shut it down. Oil compartment is slightly overfilled but not by very much.

I checked the oil and it's definitely darker than brand new oil, however it's still transparent on the dipstick. Oil fill cap has lots of water drops/condensation under the cap.

So my real question is this -- does this oil indicate head gasket issue or cracked block or does it look like regular used oil is supposed to look?
 

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alldodge

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The oil looks fine. Oil will never look as good as when it was put in because there is always some old left behind

Some condensation isn't bad and mostly normal. More so if it sits for a few days.

Might need a compression test to see if there is a gasket issue.

Is the motor closed cooling? If so you may be smelling antifreeze
 

platon20

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The oil looks fine. Oil will never look as good as when it was put in because there is always some old left behind

Some condensation isn't bad and mostly normal. More so if it sits for a few days.

Might need a compression test to see if there is a gasket issue.

Is the motor closed cooling? If so you may be smelling antifreeze

The motor is raw water/open cooling via a through hull.

The smell on the white smoke is like burning oil or rubber smell, but I checked the belt and it looks fine so I assume it's burning oil?

The oil was slightly overfilled so maybe that's causing it? But it's just barely overfilled so I will probably take it to the shop and have them take apart the engine and see whats going on.
 

alldodge

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Slight overfill should not cause oil burning,
If its a head gasket it may start to raise the oil level by water getting into the pan. If oil continues to come up then that's what it is

If it is a head gasket then water can get into the cylinders
 

GA_Boater

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It looks like you have water in the oil.
What are you basing that on? There is no evidence of water in the oil.

@platon20 - Is that fairly new oil? You recently added a thru hull water water pick up converting to an engine driven water pump. Is cooling water getting to the motor?
 

platon20

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What are you basing that on? There is no evidence of water in the oil.

@platon20 - Is that fairly new oil? You recently added a thru hull water water pick up converting to an engine driven water pump. Is cooling water getting to the motor?

Yes it's fairly new oil. I changed it at the end of last boating season in November. Since then it has sat in there and it only has about 10 hours of engine time on it since it was replaced with the oil filter back in November.

I verified that water is getting to the impeller via the through hull. Also I changed the impeller a few days ago and it looked perfect.
 

nola mike

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That oil looks brand new. Water probably won't show on the dipstick. I'd run it a bit to see what happens. More smoke? Oil level gets higher? Noises? Smoke with increased temp can be a lot of things getting hot that shouldn't be
 

platon20

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Update -- I removed 1 quart of oil and the engine ran fine. No white smoke, no bad smell, no overheating.

I don't get it.

The oil was just slightly overfilled. I guess that's enough for the crankshaft to dip into the oil and sling it around everywhere causing the burning smell and white smoke?
 

wshekar

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Dec 30, 2020
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My understanding is that agitated oil does not lubricate engines very well. Maybe that oil was thin and burning rather than lubricating.
 

ahicks

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That moisture build up is seen frequently when people get a new boat and start it up just to listen to it run for a minute, then shut it down without properly warming/running under load.

I'd check it again after you've had a chance to get it in the water and run it for a good hour to get all that crap burned off.

If there were water in the oil, it would turn milky in short order. THAT'S when you start sweating bullets....
 
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