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T500 air in oil lines

Posted: Tue Mar 30, 2021 3:31 pm
by kall399
So I have my newly rebuilt engine and oil pump. and in the lines there seems to be at all times 1/3 oil 2/3 air but no backwards pulsing. This happens no matter what way I bleed the system or pre fill the lines and I can't see any oil leak after not running that would indicate a leak in or out So is this normal? abnormal? I can't think of where it would suck in air.

Re: T500 air in oil lines

Posted: Wed Mar 31, 2021 12:09 am
by Alan H
Oil tank or pump lines and joints.

Re: T500 air in oil lines

Posted: Wed Mar 31, 2021 4:37 am
by dollydog
where on the oil lines is the air? engine end, it could be the non return valves on the end of the oil lines not seating properly. take the lines off, fill them with 2 stroke and hang them up to see if they drip - obviously the 4 banjos hanging down. if they drip then one or more ball bearings inside isn't seating properly. if the air is at the pump end, then suspect the nylon sealing washers on the banjos. if the air is in the middle it usually means you haven't bled the oil pump properly, which is a pig of a job if everything is connected. trying to get at the head of that big brass bolt on the end of the oil pump with a 17mm spanner is pretty damned difficult. what i would try first is: take the spark plugs out, undo the 4 engine end banjos, just loosen them, no need to take them off yet. get an elastic band on the oil pump lever to hold it wide open. kick the engine over SEVERAL times. you should get rid of all the air bubbles eventually. if you don't, then read the first 3 sentences again :D
cheers, dd.

Re: T500 air in oil lines

Posted: Wed Mar 31, 2021 5:46 am
by kall399
The air seems to be coming from the pump and moving with the oil the whole way from pump to engine and I can't see any backwards motion of the oil on the engine end and I know the lines lost most of the oil in them over a week when I was testing them so they leak some but I don't think its enough to cause this. And the tank line is solid with oil.

Re: T500 air in oil lines

Posted: Wed Mar 31, 2021 10:17 am
by kall399
I took a video of it running after I tried bleeding it again. And no the loose washer is not missing from a connection.
https://youtu.be/TKtw_UmIWvg