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Hey guys ,have a question for you. How long does a brand new oil sending switch usually last in these things? Seems like I’m replacing it every couple thousand miles. Is that normal? I don’t think it is maybe you guys know.
Hey guys ,have a question for you. How long does a brand new oil sending switch usually last in these things? Seems like I’m replacing it every couple thousand miles. Is that normal? I don’t think it is maybe you guys know.
every brand you can think of. Went from the cheap one to the more expensive one at the Corvette stores. It would work for a while I mean, like a couple thousand miles and then not work correctly. Add an idle it’s saying 50 psi which I know can’t be right. When I rev up the motor, the PSI goes to 80.
I've had similar results. I've tried US standard motor parts, Napa, one from Zip Corvette. Another I forget the brand from Summit.
The US Motor parts one worked perfectly for maybe 2 months, then went haywire.
I got so desperate I even changed the oil pump. No joy.
The last one sorta works. Reads high. But I know it. So I'm living with it. The original lasted 45 years.
Haven't found a reliable replacement. Let us know if you do. Or perhaps you'll just live with the one that reads high as well.
I've had similar results. I've tried US standard motor parts, Napa, one from Zip Corvette. Another I forget the brand from Summit.
The US Motor parts one worked perfectly for maybe 2 months, then went haywire.
I got so desperate I even changed the oil pump. No joy.
The last one sorta works. Reads high. But I know it. So I'm living with it. The original lasted 45 years.
Haven't found a reliable replacement. Let us know if you do. Or perhaps you'll just live with the one that reads high as well.
is it possible it could be the oil pressure gauge itself?
is it possible it could be the oil pressure gauge itself?
Yes, of course the gage may be at fault.
Suggest, FIRST acquire a Known-good "mechanical " OP gage (tubing etc) and use that to Verify your actual pressure and to help diagnose which parts of your instrumentation are faulty.
Probably get a cheapo OP gage kit on amazombie/fleabay
*some sbc blocks manufactured at Flint MI USA, have an additional oil pressure port, located at very front of block, just above top of timing cover, and plug typically has a square head.
** most sbc blocks have an additional oil pressure port, located just above oil filter mounting pad, and plug typically has a hex head.
*** Suspect 77 L82 with 80 psi indicates EITHER someone MAY have installed an aftermarket high-volume OR high-pressure oil pump.
OR, OR your gage MAY be faulty.
OR, OR your oil pump's integral bypass valve is sticking.
Last edited by Rebelyell; Oct 18, 2025 at 03:40 AM.
I'm curious what you're referring to as the "oil sending switch"
What years and s.b. or b.b..?
The early 70-72 small block system was pretty simple having a small brass fitting on the rear 'ledge' of the engine block near the base of the distributor, a length of plastic tubing of very small diameter that ran to a fitting at the back of the oil pressure gauge .
It did have a very tiny 2 piece 'collet' that fit in the end of the tubing to help keep it from collapsing. Some times this 'collet' is missing which can affect the connection and how the gauge reads.
I'm curious what you're referring to as the "oil sending switch"
What years and s.b. or b.b..?
The early 70-72 small block system was pretty simple having a small brass fitting on the rear 'ledge' of the engine block near the base of the distributor, a length of plastic tubing of very small diameter that ran to a fitting at the back of the oil pressure gauge .
It did have a very tiny 'collet' that fit in the end of the tubing to help keep it from collapsing. Some times this 'collet' is missing which can affect the connection and how the gauge reads.
Regards.....
Alan,
Of course I don't KNOW what OP's working on, but I'd clicked on his profile; where it lists a '77 L82.
My guess (if his is '77): his OE electric sender is screwed into either that rear china wall 'ledge' or, just above the oil filter mount pad.
I can tell you all. That on my 77 I have tested pressure with another gauge more than once. And if the gauge was at fault. Why does it come good with a new sender. Only to go bad again.
No, I'm pretty sure it's bad sending units. They have a diaphragm in them that is obviously not the same quality rubber as the original sender.
Oh, and it's also worth a mention. This topic has come up on this forum a number of times in recent years.
The issue is clearly a lack of quality sending units.
If the OP is installing an electric sensor, which may be correct, what about the problems associated with using thread sealant (or too much)?
Originally Posted by 4-vettes
Pretty easy to test if the sender has a good ground. And this thing about using sealant becoming a problem is a myth.
^^^THIS^^^
That old thread sealant angle is all wet. Here, they're tapered pipe threads and, as they tighten, the male & female threads cut into one another, and shear through any sealant or tape. Of sealant or tape; neither interferes with continuity or impedance.
At separate issue is impedance of present day sending units. Long ago, It was identified that few, if any, senders are available with correct impedance match to fifty year old gages. It's also just as likely that present day quality (reliability) suffers.
As for fifty year old gages; they can & do fail. But, can often be cleaned, repaired and calibrated; then returned to service "as new".
If OP's gage routinely registers 80 psi; there's another glaring clue.
A proper starting point here should be to Verify pressures with a separate, known good mechanical gage.
I tested the three C3 pressure senders I had handy. Not a single one worked. Perhaps the old diaphragms lasted longer than the new ones, but I wouldn't trust any of them.
Originally Posted by 4-vettes
Pretty easy to test if the sender has a good ground. And this thing about using sealant becoming a problem is a myth.
Oil sending switch
