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Oil pump seal/oring

9K views 13 replies 7 participants last post by  Submariner409 
#1 ·
I just finished with half case reseal and now ready to install oil pump. Was there an Oring or some kinda gasket that was to go on the backside of the oil pump. If so I have lost them. I even went to some auto part stores and we couldn't find any seals related to oil pump. There are two open areas on the pump. This pump is on a 2000 STS.

Thanks

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#4 · (Edited by Moderator)
Is there supposed to be a seal on the back left side where the recessed channel is around the hole, one side is flat with no gasket or anything and the other hole on left has a recessed channel around the hole like it should have an o ring type seal but I see no mention of it in the GM FSM. I am referring to the inlet and outlet ports I assume on the back side that faces the engine.



Well i found this a bit too late, now I see there are no gaskets used on either port.
 
#10 ·
That will work. The reasoning is that, with a totally dry oil pump, there may be a period of NO oil flow after first startup due to the pump's inability to pump air - and it's extremely difficult to prime this type of oil pump. So, the trick is to trick the thing into acting like it has oil in it - and the Vaseline or petroleum jelly immediately goes to the oil filter at first start / oil flow where it dissipates into the warming oil flowing through the filter. The dry oil pump thing is another reason you slather the internals with engine oil after a judicious coating of breakin lube. Put 1/2 tsp of engine oil into each cylinder - at first rollover that oil will lube the upper piston rings and cylinder walls.

See that large oil pressure test gauge sticking out of the pressure port on one of my Olds 455 marine engines? Without a distributor installed you can access the oil pump drive shaft and spin the pump with a long 5/16" socket to prime the entire engine before first start. Not so with our Northstars.

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#11 ·
That will work. The reasoning is that, with a totally dry oil pump, there may be a period of NO oil flow after first startup due to the pump's inability to pump air - and it's extremely difficult to prime this type of oil pump. So, the trick is to trick the thing into acting like it has oil in it - and the Vaseline or petroleum jelly immediately goes to the oil filter at first start / oil flow where it dissipates into the warming oil flowing through the filter. The dry oil pump thing is another reason you slather the internals with engine oil after a judicious coating of breakin lube. Put 1/2 tsp of engine oil into each cylinder - at first rollover that oil will lube the upper piston rings and cylinder walls.

See that large oil pressure test gauge sticking out of the pressure port on one of my Olds 455 marine engines? Without a distributor installed you can access the oil pump drive shaft and spin the pump with a long 5/16" socket to prime the entire engine before first start. Not so with our Northstars.
Thank's
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Thanks for the input Submariner, much appreciated!!
 
#12 ·
To avoid a complete dry start up with a fully charged battery remove fuel pump relay so engine won’t start. Turn the engine over so the oil pump can fill with oil before starting the engine. Still slather jelly on the pump on install still. I usually get oil pressure right away by doing the pump priming procedure above.
 
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