Help... Oil leaking from guage connection - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1971c10longbed · 12-19-2024, 05:15 PM

I replaced the copper oil line with one from LMC. Oil is leaking around the tubing at the oil gauge. The connection fitting is tight.

It is leaking around the hole where the copper tubing goes through the hole in the connection fitting.

Anyone ever had this issue and how did you fix it?

Thanks in advance

**Rust_never_sleeps** · 12-19-2024, 06:13 PM

could be the nut is tight, but the flare isn't seated properly
NOTE: It ain't a flare, see below

slikside · 12-19-2024, 06:50 PM

Quote:

Originally Posted by Rust_never_sleeps

could be the nut is tight, but the flare isn't seated properly

Yep.

Try loosening and tightening the nut several times to shape/seal the flare of the line with the guage. This is a great technique I learned here on this board for many hydraulic connections.

**HO455** · 12-19-2024, 07:25 PM

It possible you have over tightened the fitting. The fitting should be snug not tight to seal. Also did you inspect the end of the line carefully? It's possible that there is a burr or other deformity preventing the tubing from forming properly to the ferrule.

I would pull it apart inspect the end of the line for defects and then if the ferrule is still loose on the tubing try what slikside recommended. If the ferrule is tight on the tubing and the tubing is deformed by the ferrule then it's time to cut it off and start again with a new ferrule.

Good luck.

**PbFut** · 12-19-2024, 09:31 PM

If you can not get it to seal, an old trick I once used was to hole punch a piece of aluminum foil. Poke small hole in center so it will fit on end of tube fitting. It will act like a conical gasket. Worked on a truck i had 40 yrs ago.

RustyPile · 12-19-2024, 10:05 PM

Some of the "hints & tricks" offered here are for sealing a flare fitting.. The oil pressure gauge fitting does not use a flare fitting, it uses a fitting referred to as a compression fitting. Google the term and learn how the fitting works.. Do as HO455 suggested, and your leak problem will be solved...

**LockDoc** · 12-19-2024, 11:26 PM

-
Sorry, but you would all be wrong. The fitting for the gauge is called a "Compression Sleeve Nut". The stock block adapter uses the same fitting. Here is a picture of it. If your oil line has any other fitting for the oil pressure gauge it will probably not seal.

Here is a picture of it posted by LostMy65.....

Here is a "how to" thread I posted about making a new oil line with original style fittings..

https://www.67-72chevytrucks.com/vbo...d.php?t=613238
.

**Steeveedee** · 12-19-2024, 11:39 PM

I was thinking ferrules at first, but then got to thinking that I was wrong, and deleted my post. Along came LockDoc with the correct item.

**HO455** · 12-19-2024, 11:44 PM

Quote:

Originally Posted by LockDoc

-
Sorry, but you would all be wrong. The fitting for the gauge is called a "Compression Sleeve Nut". The stock block adapter uses the same fitting. Here is a picture of it. If your oil line has any other fitting for the oil pressure gauge it will probably not seal.

Here is a picture of it posted by LostMy65.....

Here is a "how to" thread I posted about making a new oil line with original style fittings..

https://www.67-72chevytrucks.com/vbo...d.php?t=613238
.

Thanks Doc,

**Papa Smurf** · Yesterday, 11:16 PM

Just had the same problem after rebuilding my dash. Go to NAPA and get the ferrule(not expensive). Cut off the old ferrule and slide the new one on then tighten. These ferrules create their own crimp and don't do well the second time around.

**PbFut** · Yesterday, 11:37 PM

You guys got wound up on this one. Instead of pointing fingers offer solutions. Maybe I was not clear enough. A compression nut seals on two surfaces. Similar to how a compression fitting works. The outside of the nut on the angle surface from threads to tip seals against the female angled surface of the guage fitting. The nut also seals to the outside surface of the tube against the surface of the hole in the nut. Both are metal to metal contact and seal using compression force as the nut pushes on the angled surface in the guage fitting. If the leak is past the nut on its outside surface and past the threads, the aluminum trick will work as it did for me. If the leak is past the nut and tube surface, then you will need to determine if you can get away with a repair but more likely need a replacement.

12-19-2024, 05:15 PM	#1
1971c10longbed Registered User Join Date: May 2016 Location: northern CA Posts: 19	Help... Oil leaking from guage connection I replaced the copper oil line with one from LMC. Oil is leaking around the tubing at the oil gauge. The connection fitting is tight. It is leaking around the hole where the copper tubing goes through the hole in the connection fitting. Anyone ever had this issue and how did you fix it? Thanks in advance

12-19-2024, 06:13 PM	#2
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 589	Re: Help... Oil leaking from guage connection could be the nut is tight, but the *flare* isn't seated properly NOTE: It ain't a flare, see below __________________ 1970 C10 Custom longbed 350/350 Last edited by Rust_never_sleeps; Yesterday at 01:49 AM.

12-19-2024, 07:25 PM	#4
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,350	Re: Help... Oil leaking from guage connection It possible you have over tightened the fitting. The fitting should be snug not tight to seal. Also did you inspect the end of the line carefully? It's possible that there is a burr or other deformity preventing the tubing from forming properly to the ferrule. I would pull it apart inspect the end of the line for defects and then if the ferrule is still loose on the tubing try what slikside recommended. If the ferrule is tight on the tubing and the tubing is deformed by the ferrule then it's time to cut it off and start again with a new ferrule. Good luck. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

12-19-2024, 09:31 PM	#5
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 629	Re: Help... Oil leaking from guage connection If you can not get it to seal, an old trick I once used was to hole punch a piece of aluminum foil. Poke small hole in center so it will fit on end of tube fitting. It will act like a conical gasket. Worked on a truck i had 40 yrs ago.

12-19-2024, 10:05 PM	#6
RustyPile Registered User Join Date: Dec 2017 Location: Elkhart, Texas Posts: 1,841	Re: Help... Oil leaking from guage connection Some of the "hints & tricks" offered here are for sealing a flare fitting.. The oil pressure gauge fitting does not use a flare fitting, it uses a fitting referred to as a compression fitting. Google the term and learn how the fitting works.. Do as HO455 suggested, and your leak problem will be solved...

12-19-2024, 11:26 PM	#7
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,769	Re: Help... Oil leaking from guage connection - Sorry, but you would all be wrong. The fitting for the gauge is called a "Compression Sleeve Nut". The stock block adapter uses the same fitting. Here is a picture of it. If your oil line has any other fitting for the oil pressure gauge it will probably not seal. Here is a picture of it posted by LostMy65..... Here is a "how to" thread I posted about making a new oil line with original style fittings.. https://www.67-72chevytrucks.com/vbo...d.php?t=613238 . Attached Images __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - Last edited by LockDoc; 12-19-2024 at 11:43 PM.

12-19-2024, 11:39 PM	#8
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,673	Re: Help... Oil leaking from guage connection I was thinking ferrules at first, but then got to thinking that I was wrong, and deleted my post. Along came LockDoc with the correct item. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

Yesterday, 11:16 PM	#10
Papa Smurf Active Member Join Date: Feb 2009 Location: Ben Wheeler, TX Posts: 119	Re: Help... Oil leaking from guage connection Just had the same problem after rebuilding my dash. Go to NAPA and get the ferrule(not expensive). Cut off the old ferrule and slide the new one on then tighten. These ferrules create their own crimp and don't do well the second time around. __________________ 72 Sierra Grande 2500 BB 72 Sierra 2500, 42K miles, factory buckets 72 Cheyenne 20 72 Chevy SWB, Factory BB, Leaf Spring

Yesterday, 11:37 PM	#11
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 629	Re: Help... Oil leaking from guage connection You guys got wound up on this one. Instead of pointing fingers offer solutions. Maybe I was not clear enough. A compression nut seals on two surfaces. Similar to how a compression fitting works. The outside of the nut on the angle surface from threads to tip seals against the female angled surface of the guage fitting. The nut also seals to the outside surface of the tube against the surface of the hole in the nut. Both are metal to metal contact and seal using compression force as the nut pushes on the angled surface in the guage fitting. If the leak is past the nut on its outside surface and past the threads, the aluminum trick will work as it did for me. If the leak is past the nut and tube surface, then you will need to determine if you can get away with a repair but more likely need a replacement.



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