air infiltration at 10,000 ft, could it be fuel pin leak?

[wisconsinjohnson]

so i just moved to a ridiculous elevation, where a k03 feels like its got enough air for about 75hp worth of fuel, which i can deal with, but now i am getting air bubbles in the clear intake line between the water separator/heater and the ip.  i just went through all hose clamps and replaced most with stepless ear/pex clamps, or new fuel line clamps, so i suspect either the o-ring on the sep/heater,  or the leaking fuel pin, which i have been trying to avoid resealing for another month or two.  I get a very minor amount of air in line at 700ft (wisconsin) not enough to affect starting down to about -5 f ,  but at 10,000ft (colorado) if the car sits for 3 or 4 hours at 20-40 deg it starts hard and there is lots of air in line, and this morning 8deg was the first time it didn't start easily, i just walked away for fear of cooking a starter, and came back after it warmed up to 18, and got it started, but i'm not sure about how to confirm where the leak is, because it only happens when the car sits, i'm hoping the altitude thing might be a clue, any insight or info on how altitude would make it more likely for fuel to siphon back to tank via aneroid leak? or separator?

thanks

[bajacalal]

My money is on the water separator.

And I can't see how the altitude would make a difference, and if it did, I think it would go the other way (leak out due to lower ambient pressure). I think it's just something that happened on your journey or was caused by your use of the car in the Rockies- extreme cold, dusty dry conditions, rough roads, maybe... more UV light (that's a stretch).

[wisconsinjohnson]

i think its the water/sep too, but i just nut and bolted the entire car prior the move, checked glow plugs, etc, and i have made two trips to this altitude, and bottom line is car has way more air in lines, way faster, at altitude, i went back to wi for a week and didn't get this much air in lines, at same temp. after letting car sit for days, came back, same problem.

[92EcoDiesel Jetta]

 Could be coming from your leaky fuel pin. there is an o-ring that's easy to replace.

[92EcoDiesel Jetta]

water separator/heater? what heater? I am not aware of a heater anywhere.