plastic oil pressure line- careful- they break

[Bob B.]

I was cleaning up in the engine compartment of my '70 convertible SB, barely touched the plastic oil pressure line and it snapped-
was super brittle. Mine was a clear plastic, the judging guide says it should be black with white lettering so who know what happened over the last 50 years- BUT just a FYI check yours, it makes a heck of a mess if the engine is running

[Joe L.]

Re: plastic oil pressure line- careful- they break

I was cleaning up in the engine compartment of my '70 convertible SB, barely touched the plastic oil pressure line and it snapped-
was super brittle. Mine was a clear plastic, the judging guide says it should be black with white lettering so who know what happened over the last 50 years- BUT just a FYI check yours, it makes a heck of a mess if the engine is running

Bob------


These oil pressure lines are nylon. Nylon becomes very brittle with heat and age. If you think a broken line makes a mess in the engine compartment, you should see what happens if it breaks between the firewall and the gauge.

[Tom M.]

Re: plastic oil pressure line- careful- they break

Thanks for this post. I asked a question a year ago regarding replacement quality and there seemed to be a no urgency to swapping out the original.
https://www.forums.ncrs.org/showthre...-quality-check

Your post at least helped put the swap of the tube on my winter maintenance list.

[Patrick B.]

Re: plastic oil pressure line- careful- they break

I had to remove the radio to get access to the fitting on the back of the oil pressure gage on my 70. No fun.

[Tom L.]

Re: plastic oil pressure line- careful- they break

The nylon line broke/cracked at the fitting above the radio. Killed the radio but I smelled oil and avoided a total mess. It's copper now.

[Bob D.]

Re: plastic oil pressure line- careful- they break

Mine on my '71 broke years ago just short of the oil pressure gauge inside the car. Had a heck of a time cleaning up the mess in the interior. I started the car and the oil pressure gauge read fine and then nose dived. Shut the engine down and started looking for the problem--smerlled oil behind the center cluster. Not fun.

Bob

[Ralph E.]

Re: plastic oil pressure line- careful- they break

Back in 1970 the oil pressure line snapped behind the gauge on my 1968 BB. With in seconds oil was everywhere. Carpet was saturated and destroyed. What a mess. If I remember correctly, replace the oil pressure line with a 1967 BB line.

[Duke W.]

Re: plastic oil pressure line- careful- they break

The nylon line broke/cracked at the fitting above the radio. Killed the radio but I smelled oil and avoided a total mess. It's copper now.

You went from the frying pan into the fire. Copper has poor fatigue resistance and is susceptible to work hardening, which makes copper brittle and subject to fracture, especially in any kind of vibration environment.

The OE C2 oil pressure signal line is COPPER PLATED STEEL. Of course some morons in the repro business decided to make them out of copper. Hey, they pass judging, right?

Back when I judged mechanical at local chapter events I made it a habit of checking those lines with a magnet. I'd say about half were non-magnetic. I didn't deduct points, but during debriefing warned the owner of the safety issue and recommended they get a proper copper coated steel oil pressure line and verify it's magnetic before installing.

On a C3 if the OE nylon line is replaced with the same wall thickness and chemical spec, it will likely outlive all of us.

Duke

[Tom M.]

Re: plastic oil pressure line- careful- they break

The vendors list black replacement tube kits as "plastic". Has anyone confirmed the black tube that vendors sell is oil/pressure suitable.
The one vendor I found shows tube by Kurtec J844 spec with 1Klb burst pressure / gas oil resistant (Canada mfg).
Vendors list 40" and 51" for the '68-'73 C3.

Do the kits bond the inner sleeve or can it be removed and length adjusted?

[Mark E.]

Re: plastic oil pressure line- careful- they break

What's a good source for the copper plated steel tubing Duke mentioned?

Why did Chevy copper plate the tubing?

[Patrick B.]

Re: plastic oil pressure line- careful- they break

The vendors list black replacement tube kits as "plastic". Has anyone confirmed the black tube that vendors sell is oil/pressure suitable.
The one vendor I found shows tube by Kurtec J844 spec with 1Klb burst pressure / gas oil resistant (Canada mfg).
Vendors list 40" and 51" for the '68-'73 C3.

Do the kits bond the inner sleeve or can it be removed and length adjusted?

The kit I got from Paragon seemed to be the same kind of nylon tube that the car came with. It did not seem inferior. The original tube inside the car was not deteriorated. The break came at the firewall where the grommet had dislodged. I attributed the failure of the tube to chaffing on the exposed fiberglass edge of the hole in the firewall. I am sure the black nylon replacement tube will outlast me by many years. I would not fear using it.

I did not try to change the length, but I think the inner sleeves just push in without any bonding material.

[Duke W.]

Re: plastic oil pressure line- careful- they break

What's a good source for the copper plated steel tubing Duke mentioned?

Why did Chevy copper plate the tubing?

Good question... why copper rather than the more common zinc or cad. I've never understood the reason.

I think most of the Corvette parts vendors have gotten the word and now sell a proper copper plated steel oil pressure signal line, but if you need one be sure to contact them before buying and have them VERIFY with a magnet that steel is under the copper plate.

Duke

[Joe L.]

Re: plastic oil pressure line- careful- they break

I did not try to change the length, but I think the inner sleeves just push in without any bonding material.

Patrick-------


They do.

[Mark E.]

Re: plastic oil pressure line- careful- they break

How does the steel line in a C2 big block differ from the small block? Length only?

I'm asking because I'm wondering which steel line kit would be the best fit for my '70 454.

[Ralph E.]

Re: plastic oil pressure line- careful- they break

How does the steel line in a C2 big block differ from the small block? Length only?

I'm asking because I'm wondering which steel line kit would be the best fit for my '70 454.

Mark, not sure how they differ, but I think if you can get a new plastic line that is the better way to go.
GM changed for a reason?? Probably cost $$$.
50 years ago, I changed mine to copper/steel line only because that is all the Chevy dealer had at the time.
My car was my daily driver while in college.