Light Aircraft Association

Dear all,

hoping that someone may be able to shed some light on this ....

I flew yesterday for an hour and it was cold, minus 4C on the ground, and when I got back looked in the engine and saw goopy stuff on the outside of my gascolator. It was soft to the touch, maybe solidified because of the cold, but what is it and where did it come from ?

The drip pattern suggested it had come from above, there was a small 'droplet' of it on the lower back edge of the generator and small splashes on the firewall behind/above the gascolator.

The engine does weep a little oil, I think it’s from the gasket on the oil sump, but this ‘mystery liquid’ was slightly more viscous, almost like waxy grease, any thoughts ?

thanks
Graham

Have you got an oil breather pipe that could be discharging thereabouts? It sounds like the sort of emulsion that sometimes exudes from these (and can get thicker and more sticky when it's cold).

Nick,

thanks for your reply, I received this suggestion from elsewhere too, and yes the oil breather is in similar place, port side of fire wall, probably 6" from gascolator.

I have also received suggestions of possible breakdown of rubber shaft seal on the generator or burned oil from a crack in the piston ring wear area of a cylinder barrel.... I have a slight oil weep which leaves oil smearing on the gascolator but this remains normal viscosity and did so on this day too, the 'goopy' deposits were something quite different.

thanks
Graham

Try taking the oil filler cap off and have a look at the underside of it. You might find more goop there...and perhaps check the breather line can in fact breath.

I have known of breather pipes freezing up in weather like this - a mate blew out a crankshaft seal last year on his Pitts.

Of course all had defrosted and was aparently OK in the hangar afterwards - that is, except for a small plug of icy emulsion goop under the outlet of the breather tube....

Hope this helps

Adrian

Thanks Adrian, and all...

when I'm able to, hopefully later this week, I'll be back at the hangar and taking a closer look. Will check all suggestions and, hopefully, have something good to report in time..

regards
Graham