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Discussion Starter · #1 ·
Any tips from senior members as to physically reaching the oil pressure sending unit? My gauge shows low pressure but I'm inclined to think that the sending unit is giving a false reading. The wire leads look frayed and the terminals are dirty. I had funky water temp readings until I crimped a new terminal on.
 

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Super Moderator
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You would actually need to make a wrench to get the sender off. I did. Bought a cheap 19mm combo, had a friend heat it and bent it in half at a 90 degree. Then on the boxed end, I got a short piece of threaded rod and two nuts. Stuck the rod through and locked it in place with the two nuts, works like a charm. You don't even have to remove the intake/exhaust manifold!!! I'll post a picture when I get home.
 

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Code Goober
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I'd be interested in knowing this as well. My sending unit looks like it has been through a shredder, and my leads need to be repaired/replaced (shorting to ground). I've put this off becuse I can't figure out the best way to get to it. Also, what's the best way to remove the sending unit from the block?

David
 

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Detritus Maximus
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The leads are easy to replace. But I've found it best to replace them all the way over to starter. Or near there. They get pretty hard and brittle from all the heat and that can lead to shorts and high resistance.

Anybody thought of making little heat shields to cover the sending unit?
 

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Geek said:
I'd be interested in knowing this as well. My sending unit looks like it has been through a shredder, and my leads need to be repaired/replaced (shorting to ground). I've put this off becuse I can't figure out the best way to get to it. Also, what's the best way to remove the sending unit from the block?

David
I hate "me too!" messages but the PO put some type of plug in where the oil pressure sender goes and I have been delaying getting to that part because of accessibility. SOOOO Me too!
 

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Discussion Starter · #7 ·
I was able to replace the leads by reaching up from under the car. Just enough room to get my arm by the exhaust manifold. Slid off the spade terminal. The ring terminal was a little harder. I attached an extension (long file with electrical tape) to a small adjustable wrench to loosen the nut. Whew! Cleaned the terminals well before putting the leads back on. I'll see if that makes for a better reading when I start her up. That will be a couple days though...radiator is out being re-cored.
 

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Sorry for the delay guys, bad weather and power outages, but, here's the tool I made to remove the oil pressure sending unit. It's missing the other nut to lock the threaded rod onto the boxed end of the wrench, but, you can get the jest here.
 

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Opeler
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756 Posts
Low oil pressure may be due to a bad pressure relief valve (located in the oil pump cover). It may be just a bad plunger (plastic) but on mine I needed to replace the whole cover (OGTS has) because the seat was really beat up.
 

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Member
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Are there 2 oil pressure relief valves?

How many pressure relief valves are you supposed to have?
I have a 71 GT and according to the manuals, it talks about one near the oil filter, but after looking at the oil pump cover I discovered a second one ....

So are they 2 relief valves?
BTW, I opened/cleaned them both and they seem to be identical!
 

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Member
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Finally, a question I can answer!!

The old engines originally had the relief valve on the body, near the oil filter. Only the later style oil pump covers that have the relief valve on the cover are available. I don't know in what year they made the change. I can't take credit for this information, it came with the pump rebuild kit from OGTS that I bought a while back. They say to shim up the old valve so it won't open, and just use the new one on the cover.

Bestus,

James
time constrained on my engine change.......
 

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Member
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I built a tool from a piece of 1/4 X 4 X 2 inch steel, and ground out a wrench head with an ane grinder. Access improved greatly after I removed the carb. By the way, I have two spare bench tested sending units. One has a damaged cover, but works fine.
 

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Discussion Starter · #15 ·
O.K. the radiator is back in, fired her up and the guage still shows low. So I'm going to replace the sending unit. Hey, Stressed. How much do you want for one of your spares?
 

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the cover is "swupposed" to protect the sender, but, with it's location, just behind the exhaust manifold, it get hard and brittle over the years and cracks off. It really doesn't matter if it has a cover or not.
 

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Discussion Starter · #20 ·
I dug this thread back up because...I noticed while replacing the "ball" on the active oil pressure release valve that with the spring as long as it is it would take A LOT of pressure to open that valve. Do I have the wrong spring? The one that's in there is about 2X as long as the hole. I haven't been able to open the "old" valve (REALLY TIGHT) to see if the cursid PO swoped springs. I am aware that the "old" valve should NOT function. What's the proper lenght of the active spring?
 
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