I have 68 850 sport spider with the 903 cc engine. I bought a new oil sending unit, which is the two piece unit with the oil light sending unit that is inserted into the oil gauge sending unit and threaded into the block. The unit came with two new copper crush washers, and it leaks bad. The photo is of the old unit, just so you can see what I am talking about. Installed, going from the block outward, there is a crush washer, then the oil gauge unit, then a crush washer, then the oil light sending unit. The leak is from the outer washer between the two units. I installed it with the new washer, and then I tried it with the old washer. Same result. Any thoughts on making it stop? Thanks!
General 850 leak from oil sending unit
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General 850 leak from oil sending unit
The crush washers are not supposed to be used twice, so replacing the old one might not show the cause. Might need to get a bagful of new washers. Fibre washers might work, but may not like the engine heat, which is why original is copper crush washers.
Remove the whole assembly and look carefully at the faces of the pressure sensor and the switch where they squeeze against the washers. If satisfied that the faces are flat and perpendicular, move onto the washers. These need to be quite snug on the thread of the switch and not too big for the face of the pressure sender. Size is everything!
If still no result, clean it all and replace. Then try to determine where the leak is, exactly. Engine to washer, washer to pressure sender, pressure sender to outer washer, or outer washer to switch. Tedious isn't it. Hopefully that'll pinpoint the area to inspect more carefully.
Good luck.
Remove the whole assembly and look carefully at the faces of the pressure sensor and the switch where they squeeze against the washers. If satisfied that the faces are flat and perpendicular, move onto the washers. These need to be quite snug on the thread of the switch and not too big for the face of the pressure sender. Size is everything!
If still no result, clean it all and replace. Then try to determine where the leak is, exactly. Engine to washer, washer to pressure sender, pressure sender to outer washer, or outer washer to switch. Tedious isn't it. Hopefully that'll pinpoint the area to inspect more carefully.
Good luck.
Thanks. The leak is always coming from the crush washer between the gauge unit and the light unit. I have no leak at the engine washer. I have had this off and on 5 times. I've tried a nylon washer, new copper crush washers, and the result is exactly the same. A constant drip. I am worried to keep tightening it, as I am using a socket and I feel like it is tight. Seems like I can always tighten it a little more, but I do not want to break or strip anything. Has anyone else experienced this? I even tried using the old light unit, but I still get the leak. BTW, the old units that I replaced also leaked. This will drive me crazy! Appreciate hearing from anyone else who has experienced this. Thanks.
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