# Oil pressure sensor...



## 1968 Q8 (Jun 9, 2011)

1968 400cid, where would the oil pressure sensor/sender be located on the engine, my oil pressure guage doesn't work and I want to check the lead/connection.

Thanks


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## BearGFR (Aug 25, 2008)

Passenger side of the block, down low, on the oil filter housing. The switch (light) or sending unit (gauge) screws into the back side of the housing. If you remove/replace it, be sure to use telfon tape on the threads and be very careful not to over-tighten it because it's easy to do that and crack the aluminum housing, creating a leak. Note that there are different components depending on whether you have a "light" or a gauge. A light uses just a simple on/off switch that closes (connects) to ground whenever there's no oil pressure. A gauge uses a sending unit that also shorts to ground at zero pressure, but otherwise provides an electrical resistance that varies in proportion with the amount of pressure. An electrical oil pressure gauge works by "reading" the amount of resistance and representing it as a pressure.

Bear


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## lars (Sep 28, 2004)

Good, accurate technical description by Bear. Here are 2 photos showing the location and the sender (the gold canister/cylinder on the oil finter housing): The one in these photos is the large canister sender for the gauge option. The sender for the "idiot light" is much smaller but in the same location.



















Lars


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## TK69tempest (Feb 28, 2011)

There is another type of oil filter adapter that Pontiac used. It oriented the filter straight down instead do at an angle. On that one the port for the sender went straight out from the adapter - right about where the bracing is on the adapter in the photo.


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## lars (Sep 28, 2004)

That's correct. That's the "B" body (full sized chassis) adapter, and it cannot be used in the "A" or "F" cars - it will hit the frame and/or exhaust, which is why Pontiac made the angled adapter for the "A" and "F" cars.

Lars


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## 1968 Q8 (Jun 9, 2011)

Great info guys and thanks for the pics...

as always, much appreciated :cheers


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## Inda_bebe (Sep 11, 2011)

Nice, this helped me out. I'm in the process of hooking up my autometer gauges


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## Inda_bebe (Sep 11, 2011)

also, could i use the oem fuel sender unit w/ my autometer fuel gauge?


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## AZGrizFan (Apr 1, 2014)

This forum rocks. Have a '69 GTO Tribute convertible and my oil light has been flickering (no gauge) at idle or when slowing to turn or stop. When I googled for an answer or possible causes, THIS forum keeps popping up! Gonna start with the simple stuff (switch) and go from there...on another forum, however, I read about something called "Mystery Oil". What is that, and could that help clean out any potential sludge that might be present and causing the oil pressure problems I'm experiencing?


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## PontiacJim (Dec 29, 2012)

AZGrizFan said:


> This forum rocks. Have a '69 GTO Tribute convertible and my oil light has been flickering (no gauge) at idle or when slowing to turn or stop. When I googled for an answer or possible causes, THIS forum keeps popping up! Gonna start with the simple stuff (switch) and go from there...on another forum, however, I read about something called "Mystery Oil". What is that, and could that help clean out any potential sludge that might be present and causing the oil pressure problems I'm experiencing?



Probably referring to Marvel Mystery Oil that is packaged in a red bottle or can. You can actually use this in your gas. I used to put 1/2 quart transmission fluid in my oil just before changing it and run it at idle for about 10 minutes. It is thin, so your oil pressure may drop. Trans fluid is a great hand cleaner as it cuts through grease and oil. BUT, although I have used it, I don't recommend using it per say. If you have sludge build up in your engine and you loosen it up, it could plug up an oil gallery, oil pump screen, lifter, pushrod, etc.. Now if you used this from the beginning of your engines life, it might be another story. I don't bother with this anymore, just change the oil & filter regularly.


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## Instg8ter (Sep 28, 2010)

Sounds like the switch Griz, probably would'nt be a bad idea to take it off and put a mechanical gauge on in the engine bay to test it and give you a true pressure reading at idle (warmed up you should see around 30 pressure). Like Jim said you may do more harm than good loosening up the sludge.


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