oil gauge sender confusion

rbuhler · 10-12-2009

I've read all the threads on oil gauges heres my deal. I just got this 1970 gt and there was a oil gauge loose on top of engine with the 2 wires connected to it but the one on the block is a single wire sending unit.I tried connecting either wire to the one on the block but the gauge goes full right as soon as you turn on the ignition. I would change the sending units but the one on the block looks like it has a bigger thread size and looks like the one in my service manuel but why would I have 2 wires. The one on my block looks like its been there since year one.

opelnut10 · 10-12-2009

Originally Posted by rbuhler

I've read all the threads on oil gauges heres my deal. I just got this 1970 gt and there was a oil gauge loose on top of engine with the 2 wires connected to it but the one on the block is a single wire sending unit.I tried connecting either wire to the one on the block but the gauge goes full right as soon as you turn on the ignition. I would change the sending units but the one on the block looks like it has a bigger thread size and looks like the one in my service manuel but why would I have 2 wires. The one on my block looks like its been there since year one.

The sending unit screwed into your engine is for a car that does not have a gauge, but has an "idiot" light on the dash. All GT's had a two terminal sender. One is for the mechanical part of the gauge and the other is for the oil pressure light. Someone more than likely changed the motor in your car with another model, you have two choices, put the right sender on the engine or screw in an adapter for an "after market" oil pressure sender.

wrench459 · 10-12-2009

Originally Posted by rbuhler

I've read all the threads on oil gauges heres my deal. I just got this 1970 gt and there was a oil gauge loose on top of engine with the 2 wires connected to it but the one on the block is a single wire sending unit.

Could you post a picture of the setup. From what I'm reading you've got two sending units?

tekenaar · 10-13-2009

Originally Posted by opelnut10

Originally Posted by rbuhler

I've read all the threads on oil gauges here's my deal. I just got this 1970 gt and there was an oil gauge loose on top of engine with the 2 wires connected to it but the one on the block is a single wire sending unit. I tried connecting either wire to the one on the block but the gauge goes full right as soon as you turn on the ignition. I would change the sending units but the one on the block looks like it has a bigger thread size and looks like the one in my service manual but why would I have 2 wires. The one on my block looks like its been there since year one.

The sending unit screwed into your engine is for a car that does not have a gauge, but has an "idiot" light on the dash. All GT's had a two terminal sender. One is for the mechanical part of the gauge and the other is for the oil pressure light. Someone more than likely changed the motor in your car with another model, you have two choices, put the right sender (360-028) on the engine or screw in an adapter (R7963) for an "after market" oil pressure sender (360-009).

As already said above, your block OP sender is for an idiot light only model, not a GT or Rallye model with OP gauge AND idiot light. That said, I've added links for the two OP sender options mentioned and the proper adapter for the 1/8" NPT "after market" sender.

rbuhler · 10-13-2009

I have an original sending unit for a GT are the threads the same for the 2 before I start taking it apart it is rather a tight work space.

opelnut10 · 10-14-2009

Originally Posted by rbuhler

I have an original sending unit for a GT are the threads the same for the 2 before I start taking it apart it is rather a tight work space.

Yes the threads are the same, to make it simple either use a thin wrench to tighten the original or grind a cheap wrench down in thickness to get in there and tighten the sender.

timemachine · 10-14-2009

Threads are the same for both senders. The old units tend to crack or disintegrate, Otto's fix is the best move IMHO and works great. (I've done the same myself)

The swap is a cinch on a Manta or Ascona, but people have struggled with the same job in the tight space in the GT. Sometimes you need a wrench to get the old one out, Kent-Moore made a tool for this once and Gene built his own.
http://www.opelgt.com/forums/6a-engi...ding-unit.html

If I were going for this in a GT I'd opt for a new unit myself.

Good luck.

Jim

10-14-2009	#7 (permalink)
timemachine Member Join Date: Jan 2006 Location: Swarthmore, PA Posts: 871 Real Name: Jim Provided Answers: 7	Threads are the same for both senders. The old units tend to crack or disintegrate, Otto's fix is the best move IMHO and works great. (I've done the same myself) The swap is a cinch on a Manta or Ascona, but people have struggled with the same job in the tight space in the GT. Sometimes you need a wrench to get the old one out, Kent-Moore made a tool for this once and Gene built his own. http://www.opelgt.com/forums/6a-engi...ding-unit.html If I were going for this in a GT I'd opt for a new unit myself. Good luck. Jim __________________ '74 Manta ("Sig") '75 Sportwagon (project) '72 GT (whenever I get to it) Sold or wrecked: '72 Manta Rallye '73 Manta '74 Luxus

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