No oil pressure

[84GMCSierra]

Good Morning Everyone
I have a dilemma going on with my oil pressure. My 84 with a 350 ha been running great, everything normal, but after I parked it at work Sunday morning and then came out and started it, to go home, I had no oil pressure. No knock or running rough. I rapped on the gauge bezel, no movement. It gas a small oil leak, so I added a bit of oil. No change. I left it running to go back in the shop and when I came back out, it sounded like it was starting to knock so I immediately shut it down and called a friend. I thought the oil pump so ordered one from O'Reilly's. When I dropped the pan, there's nothing in it. Only thing I notice is the nylon coupler for the pump shaft has a full length crack. . I'll probably pull the distributor tidy to see if something on it has broke. Adding some pics of the coupler and the bottom end of the engine. Any other things I might look for?

 

[Ricko1966]

First thing make sure it really is an oil pressure problem. Check with a good mechanical gauge. Could be the pump, a stuck bypass valve. Seen it before on a customer vehicle. No oil pressure, verified, no glitter in the pan,new pump problem solved. My own vehicle had a bypass valve that would stick when hot. No oil pressure hot,no glitter in the pan. New pump cured it.

 

[fast 99]

Those plastic collars break quite often. However, never seen it cause a problem. Believe they are for assembly only. Its rare to loose oil pressure suddenly from a mechanical issue. If the plastic collar bothers you there is an all steel oil pump drive available.

 

[peats]

Those 2 drives are not going to disengage because of a cracked plastic coupler.

 

[JamesSam]

Before all that, check and see if the oil pressure sending unit has just shaken loose. If it is still attached, possibly could be the oil pressure sending unit has run it's course. The oil pressure sender sends the signal directly to the non mechanical guage on the dash. They are not too expensive and an easy replacement.

 

[84GMCSierra]

First thing make sure it really is an oil pressure problem. Check with a good mechanical gauge. Could be the pump, a stuck bypass valve. Seen it before on a customer vehicle. No oil pressure, verified, no glitter in the pan,new pump problem solved. My own vehicle had a bypass valve that would stick when hot. No oil pressure hot,no glitter in the pan. New pump cured it.

The engine wasn't hot. My truck sat in the shade for 3-4 hours. Where is the bypass valve?

 

[84GMCSierra]

Before all that, check and see if the oil pressure sending unit has just shaken loose. If it is still attached, possibly could be the oil pressure sending unit has run it's course. The oil pressure sender sends the signal directly to the non mechanical guage on the dash. They are not too expensive and an easy replacement.

It might be bad. It's tight and the wire is connected

 

[ali_c20]

The engine wasn't hot. My truck sat in the shade for 3-4 hours. Where is the bypass valve?

Behind the pin.

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[84GMCSierra]

Thank you. I never new about this

 

[84GMCSierra]

Just curious about the difference besides size with these 2 oil pressure switches? $30 difference sure seems like an awful lot if they do the same thing

 

[Ricko1966]

Just curious about the difference besides size with these 2 oil pressure switches? $30 difference sure seems like an awful lot if they do the same thing

One is a sender for a gauge,the other is a switch for a light.

 

[JamesSam]

One is a sender for a gauge,the other is a switch for a light.

Sender(bell shaped) is the switch for an 70's -80's -ish guage.
The other skinny one is for a light on the dash(likely 88 to 90-something).

 

[Ricko1966]

Switch ( skinny) a vehicle with a light, could be damn near any year. Super common switch for decades.Just a small sample.

 

[84GMCSierra]

Update. New pump is in, new oil and filter but oils is not being pumped through the engine. Pulled a valve cover and nothing is being pumped to the rockers. Could tye oil cooler lines have anything to do with this issue? Going to pull them off tomorrow and run the pump drive and see if anything comes out of the oil filter adapter. Is there anything else I should look for or at? Everyone I talk to is as baffled as I am
Thanks

 

[Sad Sack]

Just curious but are you running the engine or using a primer tool with a drill to check oil circulation?