Factory Oil Pressure Gauge Leaking

[Already Gone]

No mine isn't leaking but something clicked on me the other night. The factory oil pressure gauge in our trucks has a " live feed " with hot oil running through it although the factory did it through copper tubing. I haven't heard of this but a friend said he has, has anyone ever experienced, or know someone who has, the oil pressure gauge blowing up while your driving and hot oil going all over the place in the cab and onto your feet. I Googled the threads here but all I could find is threads on dripping oil from the copper lines.

[72c20customcamper]

Never had a copper line or gage go . My 66 Chevelle has the original copper as does my 62 Lark . They do tend to seep after time but not drip . I have seen the plastic aftermarket tubing crack and split .

[Steeveedee]

The factory oil gauge supply lines are steel. At least the one on my truck is, and I know that it is original. I put a magnet on it just a couple of minutes ago to verify.

[Wrenchbender Ret]

I have serviced hundreds of trucks with this kind of gauge. The original tubing is steel like Steve says. The only leaks I have seen have been from the connection.

George

[pjmoreland]

I have bought a lot of gauge clusters recently and I've seen two or three where there had been a slow leak from the oil pressure gauge area. These clusters were a bit grimy down low around the gauge, but that was about it.

[dmjlambert]

I don't know if worst case scenario would be very bad. 60 psi coming through very much smaller than one square inch cross section tube is pretty much just a dribble. When I removed my instrument cluster to work on it, and I found it necessary to start up the truck and move it from one side of the driveway to the other, I just put a pan on the floor and let the tube dribble into there. I could run the engine quite a long time and accumulated just a little bit of oil on the pan.

[Steeveedee]

You're lucky. I did a similar thing on my '69 Camaro, and the oil shot out in a stream about 3 feet long. That was over 50 years ago and not something I'll easily forget.

[Already Gone]

Originally Posted by dmjlambert

I don't know if worst case scenario would be very bad. 60 psi coming through very much smaller than one square inch cross section tube is pretty much just a dribble. When I removed my instrument cluster to work on it, and I found it necessary to start up the truck and move it from one side of the driveway to the other, I just put a pan on the floor and let the tube dribble into there. I could run the engine quite a long time and accumulated just a little bit of oil on the pan.

Interesting.

[Already Gone]

I guess the line is steel. I have never paid much attention to it and when saw it it looked brown in color so thought was copper.nI see now its steel and can see rubberhose around it. Did a recent engine swap but still using original line although the gauge is not an original as was in the dash I bought from a board member and been in the truck now since 2016. Sounds like my paranoia is unjustified so will carry on with what I have now.

[dmjlambert]

Originally Posted by Already Gone

Interesting.

Well since Steven had a different experience than me, it is possible my experience is not the norm. I think some experimentation is necessary. Everybody take loose your oil tube and run it into a pan, and start up the truck, and report back your results here. :-)

[Lee H]

I've never seen an original line with the correct fittings leak. I've seen lots of leaks when folks try to use a hardware store plumbing compression ferrule instead.

[Steeveedee]

Pretty sure that the general didn't ever use copper for a pressure line. It work hardens and cracks. There's going to be engine vibration, which would be enough.

[1970 CST Short Wide]

Originally Posted by dmjlambert

Well since Steven had a different experience than me, it is possible my experience is not the norm. I think some experimentation is necessary. Everybody take loose your oil tube and run it into a pan, and start up the truck, and report back your results here. :-)

Nope

[LockDoc]

Originally Posted by Steeveedee

Pretty sure that the general didn't ever use copper for a pressure line. It work hardens and cracks. There's going to be engine vibration, which would be enough.

I respectfully disagree. The General didn't use copper tubing because of the cost differential. There are millions of feet of copper tubing used in refrigeration units that are subjected to high heat, high pressure, and a lot of vibration. Member "Tx Firefighter" said that big trucks also use it for air shifter lines.

Here are the specs for the copper tubing I use for the oil pressure lines I sell.....

Copper tubing Specs

Product Details: This MUELLER INDUSTRIES copper refrigeration tubing easily connects air conditioning and refrigeration equipment.• Connect using sweating or flare fittings• Copper tubing is nitrogen purged to reduce contaminants

Technical Specs
Item: Copper Tubing.
Tube Material: Copper.
Tube Size: 1/8"
Inside Dia: 0.065"
Outside Dia: 1/8"
Wall Thickness: 0.030"
Max. Pressure: 3074 psi
Tube Length: 50 ft.
Copper Tube Type: Type ACR Copper
Tube Shape: Coil
Soft/Hard: Soft
Application: Refrigeration
Copper Tube Coating: None
Temperature Range: 100 Degrees to 400 Degrees F
Standards: ASTM B280, ANSI B9.1


As long as the oil line is installed with vibration dampening coils as shown in this thread. ( https://www.67-72chevytrucks.com/vbo...d.php?t=613238 ) There would be no problem with copper tubing.
.

[Steeveedee]

I stand corrected.

[jumpsoffrock]

Originally Posted by dmjlambert

I don't know if worst case scenario would be very bad. 60 psi coming through very much smaller than one square inch cross section tube is pretty much just a dribble. When I removed my instrument cluster to work on it, and I found it necessary to start up the truck and move it from one side of the driveway to the other, I just put a pan on the floor and let the tube dribble into there. I could run the engine quite a long time and accumulated just a little bit of oil on the pan.

I'd like to add my own experience and say I have a '97 honda that I installed a mech oil gauge into. The engine it has operates at70-80 psi and I saw the autometer gauge maax out at 100psi when I revved it up. Someone stole the car and when I found it in an impound lot the gauge was gone and I had to drive it home right then and there.

When the engine fired a low volume slow dribble came out, but it was a constant flow. I folded the line over and held it with one hand while shifting the trans and driving home.
I have also taken apart the mech lines for older vehicles that operate a much lower psi range and it is also not a whole lot of oil.

Don't get me wrong, if you have a beautiful truck and spent an arm and a leg on restoring the perfect interior, I totally understand not wanting ANY chance of oil leaking in. But from what I've experience in my short life:
1) the oil volume is generally not much, not a "geyser".
2) catastrophic line "total blowouts" like the deepwater horizon don't exactly happen often with car oil gauges.
3) The general built something tried and true, I have also seen quite a few of these old trucks and they rarely have much more than a slightly wet spot around the fitting, probably from the last time it was removed...



Similar to the ammeters of these trucks--they are not exposed to full amperage--they use a shunt.
The oil gauges are not exposed to a genuine high pressure--I believe the gauges use a different lower pressure and calculate from that to give an approximate value.

['68OrangeSunshine]

Originally Posted by Already Gone

No mine isn't leaking but something clicked on me the other night. The factory oil pressure gauge in our trucks has a " live feed " with hot oil running through it although the factory did it through copper tubing. I haven't heard of this but a friend said he has, has anyone ever experienced, or know someone who has, the oil pressure gauge blowing up while your driving and hot oil going all over the place in the cab and onto your feet. I Googled the threads here but all I could find is threads on dripping oil from the copper lines.

The copper line didn't burst, but once after working on the Dash, I forgot to secure the nut on the back of the gauge and it popped -- once up to temperature and under pressure and hot oil gushed all over my tan suede Acme Dingo boots. I was at the gas station, I shut it down immediately and secured the nut. I tried getting the oil off the boots with talcum powder and a wire brush but they were FUBAR.

[Steeveedee]

Yeah, oil is forever. I slopped drain oil on my motorcycle boots. Well, they never rusted after that.

['68OrangeSunshine]

Originally Posted by Steeveedee

Yeah, oil is forever. I slopped drain oil on my motorcycle boots. Well, they never rusted after that.

Sad thing is, they don't make that style any more.