79 corvette No oil pressure

DL-Hamilton

DL-Hamilton

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Oct 16, 2016
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Took my 79 Corvette into my mechanic. Needed the signal light fixed and it was making a lot of noise. Just got a call from him.
There is no oil pressure in my car. It is basically sitting in the pan and not being distributed to the rest of the car. My mechanic asked me
to contact the members of the club to see if anyone else had had a similar problem before they start pulling things apart. The
car will stay with him over the long weekend as it can't be driven in it's current state.

If you have any ideas could you let me know. Would appreciate any input.
The car has been regularly maintained
over the years even though it hasn't been driven very much for the past two.
 
When you say alot of noise, like noise from where and what kind of noise ? How long have you been driving with this noise ? If the motor has no ( zero ) oil pressure then the motor will seize in minutes. Lifters will all make a rattle sound like a bunch of guys tapping with hammers on metal. It probably has a electric oil pressure sending unit back of the engine near the distibutor. If wire is off or unit is faulty thus zero reading on the guage. But if he says it is knocking cause of no pressure then the oil pump quit for some wierd reason. The pump is turned by a shaft run by the distibutor. If you pull out the distributor the shaft can be checked if not broken. If it is twisted and broken then the pump is siezed. But if the shaft is ok then you can turn it with a socket on a extension and run with a electric drill. Spinning it will make oil pressure. Now one last thing before maybe doing all that you could take off the oil filter. There is a poppet valve ( flat round circle maybe 3/8" ) in the base next to the threaded nipple that the filter screws onto. See if that valve is closed or is it stuck open at a angle. It must be closed as it is spring loaded. If it is open then you'll have no oil pressure. Just poke it with something not to damage it and see if it is free as it will move easy. Put the filter back on ( I like filling the filter with oil before spinning on, and try it. Good luck.
 
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DL-Hamilton said:
Took my 79 Corvette into my mechanic. Needed the signal light fixed and it was making a lot of noise. Just got a call from him.
There is no oil pressure in my car. It is basically sitting in the pan and not being distributed to the rest of the car. My mechanic asked me
to contact the members of the club to see if anyone else had had a similar problem before they start pulling things apart. The
car will stay with him over the long weekend as it can't be driven in it's current state.

If you have any ideas could you let me know. Would appreciate any input.
The car has been regularly maintained
over the years even though it hasn't been driven very much for the past two.
Click to expand...


I would be asking your mechanic if they tried the things Michael mentioned. If they say yes they should have a solid reason your engine has no oil pressure and a way forward. If he says say no.... find a new mechanic as fast as possible and get your car hauled there. (Do not start it)
The noise thing is not a good indication. Any experienced person with engines could recognize top end lifter chatter and bottom end knock. Top end noise is bad but if it was making noise out of the bottom it most likely you need an engine as the bearings are spun or at minimum badly damaged.
Sorry to seem negative but you basically described an engine that is or being damaged by loss of oil pressure. It can only be a few things as Michael mentioned, and is quite uncommon to occur on a well maintained engine.
Hopefully it’s not severe but it’s extremely possible the engine will have to be torn mostly down to correct the oil pump or drive. On the bright side... you can seriously upgrade your engine at the same time and come away with a fresh mill with lots more ponies for very reasonable dollars.

Hope you find the cause and it all works out for you. Please keep us posted.
 
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Thanks for the input, I posted this for another member of the Hamilton Corvette Club. I sent her your comments and will ask that she lets me know the outcome.
 
So many possibilities with this one. Something as simple as the oil pickup falling off into the pan to the other suggestion made here.

Based on cost to fix one would have to know how long it was making a death rattle. Please let us know what they find.
 
since we will wait to hear what DL finds out later, for your viewing edge-ah-ma-cation , here is what happens to the shaft that turns the pump when the pump seizes. It twists so perfect then snaps the end off, as seen compared to a good shaft. I pulled this outta a 350 Olds a few years back.

IM002686.JPG


IM002687.JPG
 
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The issue is solved, here is copy of email that describes how the low oil pressure was resolved.

Sorry, got the Corvette back but forgot to email you.

I guess when I took it in, the mechanic started it up and it was making a lot of noise, he checked the oil pressure and it was so low
he immediately turned the car off . I was lucky I didn't drive it any further or it would have seized up completely.

They replaced the oil pump and the shaft. They showed me the parts. A small cylindrical shaped piece on the top of the oil
pump had split and separated. . As he said, something had to give and that was it. That is about as technical as I can get.
A major difference in the Corvette is that before I really had to have my foot down hard on the breaks when I put it in gear
as it was racing to go. Now I have less noise and a much gentler vehicle. Much nicer to drive.

Thanks for your interest.
 
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good to hear the engine was saved. I'm curious which broke ? is it the round piece of hard plastic about an inch long or actually the shaft with a slot in it that sticks out of the pump ?
 
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