Mr. Piste
ArboristSite Lurker
Hey, everyone!
So I recently noticed that my Dolmar 7900 was leaking bar oil out of the screw holes in the crankcase. The issue was that the screws around the bar and chain oil reservoir were backing out, so I tightened them down and checked the ones around the lower-end, which were all tight and fine. I then preceded to conduct a pressure/vacuum test on the crankcase. It held pressure just fine (any amount at all, it didn't matter), but it leaked a vacuum. It only leaked a vacuum to 6 bar, though, and stopped completely and wouldn't leak off or create more vacuum. No matter what I pumped it to, it always came to rest at 6 bar.
I'm baffled with this one, because my experience with bad crank seals is that they leak either a vacuum or pressure all the way off. The saw has brand new seals, brand new bearings, a brand new crankcase gasket, and a new intake boot. Only the oil reservoir screws were a little lose, and I had been using the saw at work for almost a year with no leaks or other issues. I even built new rubber pressure/vac testing seals for it, but nothing works.
Any and all thoughts on this are greatly welcome!
So I recently noticed that my Dolmar 7900 was leaking bar oil out of the screw holes in the crankcase. The issue was that the screws around the bar and chain oil reservoir were backing out, so I tightened them down and checked the ones around the lower-end, which were all tight and fine. I then preceded to conduct a pressure/vacuum test on the crankcase. It held pressure just fine (any amount at all, it didn't matter), but it leaked a vacuum. It only leaked a vacuum to 6 bar, though, and stopped completely and wouldn't leak off or create more vacuum. No matter what I pumped it to, it always came to rest at 6 bar.
I'm baffled with this one, because my experience with bad crank seals is that they leak either a vacuum or pressure all the way off. The saw has brand new seals, brand new bearings, a brand new crankcase gasket, and a new intake boot. Only the oil reservoir screws were a little lose, and I had been using the saw at work for almost a year with no leaks or other issues. I even built new rubber pressure/vac testing seals for it, but nothing works.
Any and all thoughts on this are greatly welcome!