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How big, oil leak without dripping onto the ground

Posted By: WobblyElvis

How big, oil leak without dripping onto the ground - 06/11/18 02:24 AM

I have an 06 GM ecotec engine that was leaking oil from the valve cover on the forward side of the engine. The engine became covered in a dirty oily mess but it never dripped onto the ground so I didn't repair it for years. Finally sealed in up and the oil consumption dropped by about .2QT a month or .2QTs per 1,400 miles. I find it hard to believe all this oil was just evaporating. Is this possible?
Posted By: Shannow

Re: How big, oil leak without dripping onto the ground - 06/11/18 02:31 AM

For leaks like that, look along the roads and highways, for that oily spot just after a bump in the road.

Those incipient drops get shaken off

e.g.



So quite probably the drops are getting shaken off at places like that.
Posted By: WobblyElvis

Re: How big, oil leak without dripping onto the ground - 06/11/18 02:42 AM

In this case the oil never made it to the oil pan. I know the engine is hot and there is a warm breeze from the radiator but seems like a lot of oil to evaporate.
Posted By: Hootbro

Re: How big, oil leak without dripping onto the ground - 06/11/18 04:05 PM

Engine bays still have a lot of turbulent air in them at highway speeds. Any oil accumulation of any significance gets removed by such forces. Not a Scooby Doo mystery.
Posted By: 4WD

Re: How big, oil leak without dripping onto the ground - 06/11/18 04:35 PM

Originally Posted By: Hootbro
Engine bays still have a lot of turbulent air in them at highway speeds. Any oil accumulation of any significance gets removed by such forces. Not a Scooby Doo mystery.


Saw a video where a guy removed the hood seal closest to windshield … claimed it cooled down his engine…

Always figured what you just wrote … and even at idle hot air is pushed out the bottom …
Posted By: crazy_raccoon

Re: How big, oil leak without dripping onto the ground - 06/11/18 05:35 PM

A little different but with the Toyota 2AZ-FE motors (practically all Toyota 4 cyl vehicles from like '00 to '10) had issues with the piston rings and clogged piston oil return holes that made the engines burn oil. The problem was there were no leaks and the oil ended up burning away in the combustion chamber. People were burning upwards to a qt. of oil every 600 miles or even less miles than that.
Posted By: WobblyElvis

Re: How big, oil leak without dripping onto the ground - 06/11/18 05:41 PM

So it is possible for .2 qts/month of motor oil to evaporate from a warm engine? This appears to be what was happening. Anyone know the evaporation rate of motor oil?
Posted By: OilUzer

Re: How big, oil leak without dripping onto the ground - 06/12/18 01:22 PM

I had a car that leaked very little oil but never on the ground that I could see. Sometimes I found dead bees or other gunk kind of soaked in oil around the gasket ...
That oil did not "evaporate".

sand, dirt, etc. can also absorb some oil from underneath the engine not visible to you and fall off ...
Also some oil sludge/gunk maybe back in areas not visible ...

You are only focusing on evaporation!
Posted By: WobblyElvis

Re: How big, oil leak without dripping onto the ground - 06/12/18 01:54 PM

Oil must evaporate to some extent. If I was to oil a rusty piece of sheet metal that sat outside it wouldn't be wet/oily forever.

There is another explanation for my decreased oil consumption. When I repaired the valve cover gasket I also switched oil brands and consumption has been down since that event. I've used many different brands/types of oil but they all burned or disappeared at the same rate. I find it hard to believe that the oil type is responsible for the drop in oil consumption. This is why I'm asking about oil evaporating from the warm exterior of an engine.

Oil consumption has fallen from 1 qt/3,300 miles to a qt/4,500 miles. The engine has over 200,000 miles on it.
Posted By: FordCapriDriver

Re: How big, oil leak without dripping onto the ground - 06/12/18 02:10 PM

My Escort leaks some oil, perhaps every 2 or 3 days i find a drop or two of oil on the ground.
Often i can see a small drop of oil that hasn't fallen yet on the bottom of the oil pan.
Posted By: PimTac

Re: How big, oil leak without dripping onto the ground - 06/12/18 02:17 PM

Many of the newer vehicles have resin under shields installed so minor leaks would be caught by them instead of going directly to the ground. The heat from the engine plus air movement could help evaporate anything that is minor.

As your car has that many miles on it, a common place for oil leaks would be the rear main seal. Check that area for any leaks or seepage.
Posted By: WobblyElvis

Re: How big, oil leak without dripping onto the ground - 06/12/18 05:11 PM

There is no pan or tray under the engine and no other leaks. Oil has never made it down o the top of the pan. My money is on evaporation taking the lighter portions of the oil away.
Posted By: HammerHead0313

Re: How big, oil leak without dripping onto the ground - 06/12/18 05:24 PM

Originally Posted By: WobblyElvis
Oil must evaporate to some extent. If I was to oil a rusty piece of sheet metal that sat outside it wouldn't be wet/oily forever.

There is another explanation for my decreased oil consumption. When I repaired the valve cover gasket I also switched oil brands and consumption has been down since that event. I've used many different brands/types of oil but they all burned or disappeared at the same rate. I find it hard to believe that the oil type is responsible for the drop in oil consumption. This is why I'm asking about oil evaporating from the warm exterior of an engine.

Oil consumption has fallen from 1 qt/3,300 miles to a qt/4,500 miles. The engine has over 200,000 miles on it.


Oil selection is more important than most think, especially in older high mile engines. I had a 1999 Dodge Ram with the 5.9 and it consumed 1 Quart of oil every 500 miles using full synthetic oil; swithed to a conventional oil and it cut my oil consumption by 50% using conventional oil.
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