# Oil Pressure Sending Unit (size wrench ?)



## cij911 (Oct 25, 2017)

I need to replace the oil pressure sending unit (on my 1965 ) and am having a tough time getting a wrench on it. Does anyone know what size the base nut is (1"+ ?) and if there is a special wrench used for easy removal ? The car has Doug headers so I may need to move from above with a crowfoot wrench the appropriate size - need to buy more tools  Thanks in advance


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## Goat Roper (Oct 28, 2014)

If I remember it is a special wrench, I used my strap wrench on it.
Go easy when tightening, it is a tapered thread.


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## Nicholas (Jan 16, 2017)

I just replaced the oil sending unit on my '71 GTO. The electrical tab broke off so I bought a new one at Auto Zone for $7.00. There is a special socket that fits overtop the unit and you just ratchet the old one off. I inherited some tools from my uncle and this happens to be one of them. I know of no wrench that fits it, although there could be. I guess the next best thing might be water pump pliers if they fit.


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## Colorado67GTO (Sep 11, 2014)

I haven’t installed mine on my 67 yet so I was able to check it. The flat sides are about 1 and 1/16th. That fits pretty good with very little slop.


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## BearGFR (Aug 25, 2008)

You could always remove the whole housing - just 3 bolts - then do the job with it off the car. Like Goat Roper said - be careful about over-tightening it. It's very easy to go overboard and crack the housing. Voice of experience here...

Bear


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## cij911 (Oct 25, 2017)

Thanks Gents! I will look at taking the housing off I guess (although that might be a royal PITA with the headers).....Amazing how the easiest of tasks on a 53 year old car can become a challenge....sigh


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## cij911 (Oct 25, 2017)

Nicholas said:


> I just replaced the oil sending unit on my '71 GTO. The electrical tab broke off so I bought a new one at Auto Zone for $7.00. There is a special socket that fits overtop the unit and you just ratchet the old one off. I inherited some tools from my uncle and this happens to be one of them. I know of no wrench that fits it, although there could be. I guess the next best thing might be water pump pliers if they fit.


Can you post a picture of this tool ? I am always looking for an excuse to buy more tools


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## Goat Roper (Oct 28, 2014)

Here is a selection.
You only need to hand tighten then 3/4 turn.
A tiny amount of pipe dope, I prefer Rectorseal T plus 2 teflon paste.

https://www.google.com/search?rlz=1...0....0...1..64.psy-ab..0.0.0....0.4vJhPP3AYJs


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## BearGFR (Aug 25, 2008)

Ooooooo! An excuse to buy more tools! 

I just ordered this...

GearWrench 41720 8 Piece Sensor & Sending Socket Set https://www.amazon.com/dp/B0012SCXHW/ref=cm_sw_r_cp_apa_tnY2Ab2K609DW

And I hear you on the headers, they're a pain pretty much everywhere. My plan for when I but my bullet back into the car (hopefully soon now) is to use studs instead of bolts so that I can 'hang' the headers on them and thus not have to try to hold them up and start bolts while I'm blind and standing on my head. 

Bear


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## cij911 (Oct 25, 2017)

None of those sockets would would on the 0-60 psi sensor....


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## PontiacJim (Dec 29, 2012)

cij911 said:


> None of those sockets would would on the 0-60 psi sensor....



There are are couple styles of oil sending units. One is more like a cannister that has a nut at the base and uses a wrench to take it off - uploaded a photo of it. The other type uses a special socket. They are generally not that tight and I recall using a pair of channel locks to grab it and turn it off. However..... 

Bring the sending unit to Auto Zone or any other parts store and tell them you need the socket for the sender. They should have one or can order one.

Also as mentioned, you could pull the oil filter, then remove the three bolts that hold the oil filter adapter onto the block and drop it so you will have easy access in replacing the pressure switch. You may or may not need a new gasket that goes between the block and the oil filter adapter as it may tear. If it does not tear and sticks to the filter adapter, then use a little gasket sealer on it making sure it does not end up in the oil passages (here is where I like Permatex Indian Head Gasket Shellac Compound found at your auto parts store as it applies with a brush in a thin controllable layer). Thread the bolts in by hand then torque to spec.


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## cij911 (Oct 25, 2017)

Thank Jim - it is the pressure sending unit (canister).


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## Pinion head (Jan 3, 2015)

Original '63-67 Pontiacs with factory Rally guages used a shorter cylindrical mitered dome top oil sending unit. Much different appearance than the $20 parts store Rally guage version Jim has put up a pic of. The original very early style rally guage sending unit I'm looking at has a 13/16" "nut" shaped appendage stamped into the bottom side, no socket is going to reach it, have to very carefully use an open end wrench. Personally, in yards, or in the garage, I've always removed the oil filter adaptor to get this style of sending unit off. This style of appearance rally guage oil sending unit disappeared around '67 & is very expensive, today, to find in working condition. Early A-body and B-body's with factory rally guages used different independence sending versions, one can not use a B-body one with an original '65, 66, 67 set of Pontiac A-body rally guages.

For '68 (may be earlier) the rally guage oil sending unit became longer in shape, similar to the pic of the generic aftermarket rally sending unit Jim put up. The '68-aprox '73 model rally oil sending units are part numbered & date coded & very visibly have a different shaped domed top on them than the later Introl and aftermarket versions. The first several years, '68-69, part of 70, this style rally sending unit canister shaped body had a light gold cad appearance which fades with time. Sometime during the 1970 model year, the original finish of the "cannister" changed to a semigloss black. in 73(?) the more generic Introl canister style rally guage oil sending units were introduced. The Introls were used up, at least into the early '80's. The latest style is easiast to find, USED with '77-79 inscribed dates, as every '77-79 TransAm with a 403 engine had one, & they are mounted up front going into the block near the Old's engines oil filler neck. Was very easy to pull, through the 90's when I was on road a ton, have litteraly pulled a bushel basket full of this later style, many were sold off wiith original rally guages sets for '69-mid '72 model A-body's.


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## Pinion head (Jan 3, 2015)

Nice used as well as nos early Pontiac B series Rally guage oil sending units have typically been much easier to find than original early Pontiac A-body versions. 










earlier image must be too big...
Image of an original is in following old HPP article, thanks to article from Scott Tiemann. 

http://www.hotrod.com/articles/detailing-tiemanns-tri-power-389-part-2/


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## PontiacJim (Dec 29, 2012)

Pinion head said:


> Nice used as well as nos early Pontiac B series Rally guage oil sending units have typically been much easier to find than original early Pontiac A-body versions.
> 
> 
> 
> ...



Here you go. Added just the picture of the oil pressure sending unit.


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