oil streaks

[rwarre]

Have oil on the left side of the cowling on my RV7a. Also some on the front wheel pant. The engine has 1000 hours on. I have check the engine and cannot find any leaks. Could this be a front seal?

[Kyle Boatright]

It could be that, an oil return line, or a bunch of other places. You may have to look repeatedly to locate it.

Do you have a friendly local A&P who could take a look the next time you have the cowl off?

[Carl Froehlich]

If it is on the front wheel pant, odds are it came done via the nose gear fairing. It is real easy for oil that spilled when pulling the oil filter or any fitting/gasket on the back of the engine to find it's way to the nose gear engine mount weldment - and from there down the nose gear fairing.

I chased a minor leak on the 8A for a couple of years. I'd do something and it would get better, then back again. At long last I found the fitting for the oil pressure sender hose to be loose. Not much, but enough to leak.

Carl

[Pat Stewart]

Do you have an air oil separator. I had a similar problem. Removed it and no more oil.

[Vlad]

Could be the breather. Oil is dumped on engine mount then swirls elsewhere.

[Steve]

My ECI engine developed an oil leak after 600 hours. I degreased the engine and rinsed it with water. I let the engine dry completely then sprayed it with Bond aerosol foot powder. I taxied the plane around the hangars for 10 minutes. As plain as day, there were two trails of oil coming from the oil pan-to-engine case seam. It was a simple and low cost diagnosis effort. The repair, however took about $150 in gaskets, hoses and fasteners and 8 hours time.

[painless]

I've had a nagging oil leak that presented itself as oil on my nose gear wheel pant. Oil was running down the gearleg and then onto the pant. Would even see an oil drip on the nose gear wheel pant the next time I would fly.

Oil was present on the bracket mounted to the carb that supports the throttle and mixture cables.

Long story short, previous owner of the engine, an O320 E2D from a Cardinal had over-torqued and stripped off the head of one of the bolts securing the oil pan. Repaired, and now no leak.

[rwarre]

Thanks for all the replys. The oil is coming out mostly where the fiberglass cowl meets the metal fuselage. I am wondering is would come out the whistle hole in my breather tube. Also found small amout of oil where it had spilled a little when adding to the filler tube.

[DHeal]

It amazes me how a little bit of liquid (oil or rainwater) and fretting aluminum (e.g., cowling piano hinges, fiberglass rubbing on aluminum, etc.) can combine to produce visible streaking on cowlings, airframe parts, etc. Often, there is no "leak" -- just rainwater or minor seepage washing out the fretted material. "Smoking rivets" are one example of such wear.