mobilepolice
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- Jun 16, 2013
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I've been chasing some weird moisture-after-shutdown issues that's only affecting my left engine and not so much on the right (resulting in a rusty oil cap)
iron is a little elevated in the oil samples too, but that could just as easily be flakes of rust falling off the oil cap into the pan.
On a hunch I examined the hoses feeding the air/oil separator, thinking that moisture is not getting out of the system like it should during normal operations.
For some odd reason, the left engine and the right engine had different drain hoses, or at least different part numbers. the left hose was also swollen, like it was a natural-rubber hose that was exposed to oil and fuel.
Here's some photos:
This is the hose from the separator to the engine case on the right engine that doesn't give me any trouble. I'm guessing the stamp means Mfg date of 2nd Quarter, 2006. MIL-6000 Spec?
Here's the left engine hose. 4th quarter, 2004. MIL-6000 ?
Here's the cross section of the left hose down the middle of the hose. That's far smaller than 1/4"
Here's the side that was connected to the separator. See how it is swollen?
WTF is going on here? I thought MIL-6000 spec hose should stand up to practically everything thrown at it?
The left hose was so jammed up by that narrow opening that I couldn't get any air through it at all. This whole air/oil separator system works on a principal of draft suction. There's some sort of Y-adapter where the two hoses meet, the oil hose joins the main hose which is pressurized air from the vacuum pumps sucks oil from the air/oil separator.
Right engine hose has not suffered this fate, so I'm curious if anyone has seen this before. Do these things just swell up after a time? I suppose I never expected a mil-spec hose to lose more than half it's flow cross section in an application it was designed for.
iron is a little elevated in the oil samples too, but that could just as easily be flakes of rust falling off the oil cap into the pan.
On a hunch I examined the hoses feeding the air/oil separator, thinking that moisture is not getting out of the system like it should during normal operations.
For some odd reason, the left engine and the right engine had different drain hoses, or at least different part numbers. the left hose was also swollen, like it was a natural-rubber hose that was exposed to oil and fuel.
Here's some photos:
This is the hose from the separator to the engine case on the right engine that doesn't give me any trouble. I'm guessing the stamp means Mfg date of 2nd Quarter, 2006. MIL-6000 Spec?
Here's the left engine hose. 4th quarter, 2004. MIL-6000 ?
Here's the cross section of the left hose down the middle of the hose. That's far smaller than 1/4"
Here's the side that was connected to the separator. See how it is swollen?
WTF is going on here? I thought MIL-6000 spec hose should stand up to practically everything thrown at it?
The left hose was so jammed up by that narrow opening that I couldn't get any air through it at all. This whole air/oil separator system works on a principal of draft suction. There's some sort of Y-adapter where the two hoses meet, the oil hose joins the main hose which is pressurized air from the vacuum pumps sucks oil from the air/oil separator.
Right engine hose has not suffered this fate, so I'm curious if anyone has seen this before. Do these things just swell up after a time? I suppose I never expected a mil-spec hose to lose more than half it's flow cross section in an application it was designed for.
