Oil pressure sender / gauge error | 1966 Riviera 425 Nailhead

[Stickybit]

Hi all

Got a "new" Riviera with a 425 engine - and I'm a bit concerned that the oil pressure sensor or gauge may be faulty.

First of all - the sensor more or less looks like the one on the attached image - and it seems to measuring roughly 55 ohms at idle, and lowering the resistance to roughly 20 ohms when speeding up the engine. This tells me that oil pressure is present and probably just fine - and that the sensor is doing some kind of work.

The question is - would this sensor be the correct model for this engine? - because the oil pressure gauge kinda just either do nothing, or it just bangs the needle to the max.

Is there a trick to do a quick test oil of pressure? - while not having a oil pressure tester at hand?

Best regards, Søren

 

Edited April 24 by Stickybit (see edit history)

[NTX5467]

I suspect the sender might be a "will fit, looks like it will fit" rather than what it really needs.  You might go into www.rockauto.com and input your vehicle information for a new sensor (what GM calls it) and see if any of the markings on the unit match the part numbers of the brands RA has in their product listings.  Not an exact situation, but about the only thing I can think of except using a manual gauge to verify your readings.  No banging should be the ultimate result.

 

In some cases, the part number is stamped on the hex where the threads are, or at least the max psi for the gauge calibration.  Might need a mirror or use your phone to get a picture, carefully.

 

Just some thoughts,

NTX5467    

Edited April 25 by NTX5467 (see edit history)

[60FlatTop]

When in doubt put a test gauge on it.

[telriv]

I don't trust ANY of the electrical gauges. too many variables'.

Mechanical ONLY in my opinion.

 

Tom T.

 

[Stickybit]

Regarding the currently fitted pressure sensor - is the measurements  60 - 20 ohm (roughly) what would be expected for ´66 425 engine sensor? - or is something else to be expected (since the gauge seems to have a life of it's own).

Best regards, Søren

[1965rivgs]

41 minutes ago, gungeey said:

See below for correct application. They are readily available. It calls for a special socket as shown.

Do as 60FlatTop shows and while the unit is out check your pressure at hot idle.

If you're engine runs quiet you have enough oil pressure. If you didn't have enough oil pressure it would let you know 👍 

Look long and deep enough you can always find a problem. 

Steve, you pictured the switch for the idiot light; the `66 uses a sender for a gauge.

[gungeey]

I stand corrected and fixed it

[1965rivgs]

  Here are pics of an original '66 sender. I believe the "60" on the sender signifies it is a 0 to 60 ohm sender and the stamped part number, 6460470, is the correct part number in the Buick parts book.

  For what it's worth, the few times I've worked on the factory sender/gauge I've found them relatively worthless. If you want to closely watch the numerical values you'll need to go to an aftermarket gauge

Tom Mooney

[telriv]

An after market mechanical gauge.

 

Tom T.

[Turbinator]

I use mechanical Bosch water temp gauge and mechanical oil pressure gauges. Fitted where the ash tray was once located. When Idiot lights turn on I view the signal as “ too late.”

Actually, I regard mechanical gauges more accurate and easier to install. In summation : to each his own.

Later Gator

[NTX5467]

My observation has been that the number stamped on the sensor is to match the gauge upper limit rather than the ohms max.  Seemed to correlate to me as being "pressure".  FEW people understand "ohms", but they know about "pressure".  BTAIM

 

I've found factory gauges (of any brand) to be two things.  Accurate enough and "for reference".  BUT you have to check them to see what they are doing!  

 

Happy Spring!

NTX5467

[1965rivgs]

9 hours ago, NTX5467 said:

My observation has been that the number stamped on the sensor is to match the gauge upper limit rather than the ohms max.  

 

  Yes, POUNDS, not ohms. Communicating to the OP that the original sender as per part number is for a 60lb. gauge.

  There are several choices on the Napa website with good specification info. WARNING- I did not check specs to determine which sender, if any, correlates with a 60 lb. gauge

 

https://www.napaonline.com/en/search?text=oil pressure sender&referer=v2

 

Tom Mooney

Edited April 26 by 1965rivgs (see edit history)

[RivNut]

I have what appears to be an OE '66 oil pressure sender.  If you're interested, send me a PM

 

Ed

[Stickybit]

Sorry the for late reply. 😮

I did a quick and dirty, and just ran the engine at idle speed with one valve cover removed from the engine - and saw the oil flow just fine. Yesterday I revisited the non-problem, and tested the pressure with a test gauge, and it produced 40 psi of pressure. All in all .. no problem with the oil flow as expected. 🙂

Best regards, Søren