Best method to seal oil pressure line

[David K.]

I installed a new oil pressure line from the block to the guage. I am having no problem with leaks at the guage,but I sure am at the block. What have most used as a good sealer between the fittings and the fitting and the block. Teflon tape, pipe dope or nothing at all?

[Gary C.]

Re: Best method to seal oil pressure line

Dave, I use aircraft type fuel/brake sealant on all those kinds of connections and it works good. http://www.aircraftspruce.com/catalo...ezturnlube.php

Gary....

[Mike M.]

Re: Best method to seal oil pressure line

about 45 years ago, an ole plumber gave me some advice: " when ya think the fitting is as tight as it ought to be, give it another 360 turn". i've not had to use any sealers on any of the many sbc and bbc chevy engines at their oil pressure fittings. mike

[David K.]

Re: Best method to seal oil pressure line

The reason I asked, is the new oil line kit came with fittings and when tight, they leaked. I then bought new fittings and used teflon tape. I tightened till I was scared I would break the brass fitting in the block. It still leaks, pretty much. I purchased two sets of fittings to give it a try tomorrow. I am using line wrenches to be carefull I do not distort the fittings as well. So I will try it anyway I can to stop the leaks.

[Chuck S.]

Re: Best method to seal oil pressure line

Another option is to use teflon paste pipe sealant...it's in the plumbing department at home stores right next to the "Rectorseal" pipe dope. Apply it away from the end of the fitting, and use enough to just fill the threads. After tightening, wipe away any sealant that remains on the outside of the fitting, and no one knows you used it.

[Stuart F.]

Re: Best method to seal oil pressure line

David;

Please make sure you actually have the correct fittings. I've had mine off and on several times at the block and have NEVER encountered any leaks there. I don't recall the exact fittings used, but there are a number of possiblities. As I recall, there is an adapter brass fitting into the block that accepts the copper tube and brass fitting, but I don't recall if it was flared or a pinch type fitting (what ever they are called), but mine always sealed easily (mine is the 340 hp 63 w/hp gauge too). My problem has been with a leak at the borden tube fitting at the gauge.

Just make sure you don't have mismatched fittings is all.

Stu Fox

[Robert C.]

Re: Best method to seal oil pressure line

It's amazing how much oil will travel through that little tube! And how fast! I thought I had everything all tight on my L-T1 gauge, Started the car and within 30 seconds I had almost All the oil in my engine drain onto the floor of my car. It took a year to get it all up. Thank God for black carpets.

[Chuck S.]

Re: Best method to seal oil pressure line

...I don't recall if it was flared or a pinch type fitting (what ever they are called)...

Compression fittings is the label you're thinking about, Stu...in fact the later cars with plastic lines have compression fittings evidenced by a tiny ferrule that slips over the tube. After the fitting has been tightened once, that ferrule is permanently installed on the line; there's no getting it off.

Compression fittings is one case where "tighter" is not necessarily better. I have used a lot of copper tube with brass compression fittings, and have found that snugging them just tight is as good as it gets. If it leaks after snug tight, further tightening almost invariably makes the leak worse as the ferrule deforms inside. If a compression fitting leaks after tightening, it's better to just cut off the end of the tube with the ferrule, and try another one...this assumes you have enough tube left to reach after you cut the fitting off.

A flared fitting should also be easy to identify; the male end will have a conical taper after the threads to a smaller hole, and when you look inside the female tube end fitting, you will see the flare on the end of the tube. Most automotive applications have a flare fitting that has a slightly tapered end on the male fitting nut that fits into a "flare" machined into the bottom of the female thread.

[Stuart F.]

Re: Best method to seal oil pressure line

Thanks Chuck for coming forward with the "compression fitting" description. My mind is mush here lately due to my Arthritis pain. The simplest recollections escape me. But, I think I made the point anyway about potential mismatched fittings. I've seen people try to attach the tube directly to the block before w/o the adapter, and it's kinda hard to see down there.

Stu Fox

[Stephen B.]

Re: Best method to seal oil pressure line

If it is a plastic line there is a skinny piece of hollow brass that goes inside the plastic tube to keep it from collapsing in on itself when the ferrale is sealing and being crushed steve

[John H.]

Re: Best method to seal oil pressure line

If it is a plastic line there is a skinny piece of hollow brass that goes inside the plastic tube to keep it from collapsing in on itself when the ferrale is sealing and being crushed steve

That's correct - if you try to use a plastic (nylon) line without the tiny internal brass sleeve with the GM-proprietary taper-lock fittings, it will leak. Guaranteed.