Oil - Siphon Effect

[cab83_750]

So we all have the oil lines running to the front of the car. At oil change, with the engine hot, is there a siphon effect if you drain the oil from from the tank? Or from the engine? Will the siphon effect suck out (drain) the oil from the lines/cooler.

I have always accepted the fact that the oil in the lines remain there; thus, the ER lines have that nipple to inject air into the lines.

[ossiblue]

Interesting question. My guess would be that since the system is vented through the oil tank breather and crankcase breather, no vacuum could exist (inside the tank) that would siphon the oil from the front lines.

[cab83_750]

What? No scientist tonight? Hmmmmm.......

[aigel]

Not sure what the ER lines and nipples are, you are talking about? No such thing on a 911.

The system holds about 14 quarts of oil. Only 9-11 will come out when you change the oil. No siphon effect. This drives some people nuts (all that nasty old oil staying in there ) and it has led to some hilarious threads on here.

George

[cab83_750]

Originally Posted by aigel

Not sure what the ER lines and nipples are, you are talking about? No such thing on a 911.

George

George,

There is such a thing on a 911 Where have you been? Better yet, maybe I misread....so where have I been? English ain't my motha' lingo.

The ER lines have an air nipple. You use your compressor and insert air, thus blowing the oil out.

Check out the 'purge valve' here: http://www.elephantracing.com/oilhandling/oilines.htm

[Flieger]

He means Elephant Racing finned oil lines. They are finned Aluminum for better cooling and also have a Shraeder (sp?) valve that allows them to be slightly pressurized with a compressed air fitting when changing oil to blow the old oil out of the auxiliary oil cooler loop.

[aigel]

I thought you had some fetish with emergency room nurses ...

That is a neat feature. I'd only bother if I blew the engine though. A few quarts of old oil won't hurt if you keep adding new stuff frequently.

Cheers,

George

[tcar]

Back to original post...

Cannot siphon if the thermostat is closed.

No big deal to leave a quart or two of the older oil in with the total volume we're talking about.

[ossiblue]

Originally Posted by tcar

Back to original post...

Cannot siphon if the thermostat is closed.

No big deal to leave a quart or two of the older oil in with the total volume we're talking about.

True, but the original post specified, "when the engine is hot," and therefore the thermostat open (at least hypothetically.) Under those conditions, I suppose it would be possible to elevate the front of the car so that gravity would cause the oil to flow toward the tank from the cooler. Then, a siphon effect could drain the oil from the cooler. That's a lot of effort for a couple quarts of oil.

[Formerly Steve Wilkinson]

You can always braze a Schraeder valve onto the existing bronze/brass oil line. By the way, be extremely careful, if you do, about the amount of shop-air pressure you use. A little goes a long way. I remember once exploding an aircraft fuel tank by pressurizing it with "a little" air to find a leak.

[911pcars]

Assuming the thermostat is open, no syphon effect unless negative pressure (vacuum) is involved. A vent valve on the oil cooler or line would help. A schraeder valve on the oil cooler or line (ala ER's) provides a more positive effect.

Sherwood