I have been flighting an oil leak on my IO540 C4B5 for a few years but it just recently got noticeable worst.
The oil is found on the left side of the motor 2-4-6. It appears to start just forward of 4 but the majority of it is aft of 4 and the confusing part is I am seeing oil on the back of my fill tube.
It recently got worst and now oil will start to stream from back of my oil door on to the cowl and windshield - this was still a very minor amount 1 QT per 3-4 hours.
Trying to back into this - it may be that I don't have a great seal on my oil door and some ram air is flowing up and out the door seam caring oil with it that coats the back of the oil fill tube???
I also see oil on the #4 cylinder fins outboard - a little on 6 as well - but again the worst of it is inboard aft of #4. I see quite a bit below the cylinders aft left side along the seam between the sump and case.
I haven't isolated it to push rods - though I haven't 100% ruled them out.
One thing I did catch was the lower & fwd 3/4in bolt on #4 wasn't fully seated - fwd upper 3/4 bolt on #4 was also loose ~ 1/4 turn - So I removed the baffling and retorqued all the bolts on 2,4&6. Using a A&Ps new Torque wrench. Note I did not loosen any bolts but put the wrench on them in the star pattern and torqued them wet to the values called out by the manual.
That didn't help - now the oil leak is worst - causing oil to go through my side cowl cooling fins and the seam between cowl and firewall and trailing down the left side and bottom of the plane.
Any suggestion would be appreciated.
Thanks
The oil is found on the left side of the motor 2-4-6. It appears to start just forward of 4 but the majority of it is aft of 4 and the confusing part is I am seeing oil on the back of my fill tube.
It recently got worst and now oil will start to stream from back of my oil door on to the cowl and windshield - this was still a very minor amount 1 QT per 3-4 hours.
Trying to back into this - it may be that I don't have a great seal on my oil door and some ram air is flowing up and out the door seam caring oil with it that coats the back of the oil fill tube???
I also see oil on the #4 cylinder fins outboard - a little on 6 as well - but again the worst of it is inboard aft of #4. I see quite a bit below the cylinders aft left side along the seam between the sump and case.
I haven't isolated it to push rods - though I haven't 100% ruled them out.
One thing I did catch was the lower & fwd 3/4in bolt on #4 wasn't fully seated - fwd upper 3/4 bolt on #4 was also loose ~ 1/4 turn - So I removed the baffling and retorqued all the bolts on 2,4&6. Using a A&Ps new Torque wrench. Note I did not loosen any bolts but put the wrench on them in the star pattern and torqued them wet to the values called out by the manual.
That didn't help - now the oil leak is worst - causing oil to go through my side cowl cooling fins and the seam between cowl and firewall and trailing down the left side and bottom of the plane.
Any suggestion would be appreciated.
Thanks