Copper or Plastic on Mechanical Oil Pressure Guage

[cheap bronco]

Copper or Plastic Tubing on Mechanical Oil Pressure Guage

Hello to all. Well after numerous attempts trying to remove the oil pan without pulling the engine, to see about my oil pressure issue I gave up and pulled the engine, changed the rod bearings checked the main bearings and buttoned everything up. Now I cant say for sure if its the bearings or not since I also stretched my oil relief spring .100. The bearings showed a bit of wear bit I dont think it wouldve caused a knock, but oh well its done now. I started the engine with a short piece of plastic tubing on my mechanical guage and at cold start up I get 60 psi, after warm up it drops to 20-25 psi. Im happy. Now on to my question. I know everyone is head over heals for mechanical guages but not me. Im simply not a fan of having any kind of pressureized fluids in the cab (oil or coolant). But if need to do it ill do it. I feel it would be safer with copper tubing on the oil pressure guage rather than the plastic ones. What does everyone else use, and are you comfortable with your decisions? Thanks again in advance for your honest opinions.

 

[OLDBULL8]

Plastic is OK as long as you use the black high pressure airline tubing and the fittings for it. If using this, make sure you use the tubing insert so the brass ferule can't squeeze the tube. Tighten just enough for no leaks.

Copper line takes the brass ferule for the fittings, these are OK as long as you don't crunch the ferule into the fitting too much, tighten just enough for no leaks. Don't use a flare fitting, unless you can double flare it like brake line tubing.

When I use either, I tighten the ferule just enough to grab the tubing, test by trying to pull the tube out of the fitting, leave at least a 1/4" of tube out of the ferule.

 

[TWeatherford]

I would be concerned with copper work hardening and cracking. So I would go with plastic. But I much prefer an electric gauge.

 

[franklin2]

I have used plastic on all my mechanical guages. I believe once I had a leak, and it didn't spray hot oil all over the place like you would think. It's more of a drip drip type of leak. The line is pretty small.

 

[riotwarrior]

THIS...though a bit costly...is the answer to your dilema IMHO and the route I'm taking

Already have the LOW pressure one for my fuel pressure gauge.

http://www.autometer.com/cat_accessoriesdetail.aspx?vid=164

Hope that helps you feel safer!

 

[ToughOldFord]

Copper. That plastic stuff gets brittle and breaks too soon/easily.

When you use the copper it's a good idea to coil a couple of loops on the engine side to help absorb the vibrations of the engine.

 

[icanfixall]

An isolator is the right idea. Personally I have used both electrical and mechanical gauges. I like mechanical and I ran the copper oil line into the cab. Got well over 100,000 miles and no leaks. Only once did I have pressure issues. Turned out when I cut the copper line I went too tight on the tubing cutter blades and did not "clean out" the ends. So pressure would come up really slow and drop really slow. I even remove the line from the gauge and had a bucket for it to run into in the cab. Started the engine cold and got no oil for the longest time. Then it barely flowed out the open line. Finding the mistake took many hours too. Finally removed the line at the turbo Tee and the dash gauge. Got a bath right away too. Real surprise to find my issue was not cleaning off the end of the copper line like you do on larger copper line. Was a hell of a deal finding something small enough to open up the cut line.
Now about stretching the spring. It will help for a short time. Problem is the spring drags on the regulator body and flattens out. Then you loose part of the spring tension. I now run all Isspro EV electric gauges.

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[FarmerFrank]

I don't mind using plastic air brake line (syn-flex if you familiar with trucks) like old bull said. That stuff works for tranny coolers, fuel line, oil line, and even air line!!

My absolute favorite to use in my pickups is a mechanical gauge out of a peterbilt with a #4 fitting in the back and a #4 hydraulic hose for the line

 

[cheap bronco]

Now about stretching the spring. It will help for a short time. Problem is the spring drags on the regulator body and flattens out. Then you loose part of the spring tension. I now run all Isspro EV electric gauges.

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Thanks for your input Gary, How does one go about getting a new spring?, when ours wears out. I presume the only way is the bone yard. If we get lucky at the bone yard im sure that one will be the same way. So are we just screwed when it comes to oil pressure and this spring.?

 

[The Warden]

I would be concerned with copper work hardening and cracking. So I would go with plastic. But I much prefer an electric gauge.

I asked this question many years ago after a plastic line broke on me (see below for details), and the general consensus at the time was the same thing...that, with copper, you risk the line becoming brittle and breaking, especially with the vibration you get from a diesel. I also asked about braided stainless, but it was pointed out to me that the braided stainless is really just a sheath, and actually can make matters worse since it hides the condition of the hose underneath. For these reasons, sticking with plastic was strongly recommended at the time...I ended up going that route, and it's been serving me well so far! I do keep an eye on it, though...I'm contemplating getting new gauges, and I think I may go electrical this time around, but haven't made a final decision yet.

I believe once I had a leak, and it didn't spray hot oil all over the place like you would think. It's more of a drip drip type of leak. The line is pretty small.

In my experience, that isn't universally true. As I mentioned above, I had a plastic line let go on me...this was in late 2001 or early '02, shortly after I inherited the truck. The line broke right at the fitting on the engine (it was/is where the factory sender would go), and it sprayed oil all over the firewall and made quite a mess of the back of the engine compartment. It let go while I was driving at 65 mph with a T-19 and 4.10 gears (no tach, but the RPM's had to have been pretty high), and I didn't realize there was a problem until the valve lifters started starving for oil and the engine started ticking The really funny thing is, the gauge was still registering...I didn't have a light in the gauge (THAT got remedied immediately after this incident), but when I heard the ticking I turned the dome light on and the gauge was showing 20 psi and bouncing around a bit. I immediately shut the engine down and coasted to an offramp and off the freeway...after getting the truck towed home (an adventure in and of itself!), I found that the plastic line had broken off the fitting almost completely. I want to say I put 7 or 8 quarts of oil in before the level was back in the "safe" range on the dipstick, but it was long enough ago that I don't remember for certain now. I had been driving maybe 15 minutes before this happened, and I had checked under the hood earlier that day and all was well, so I think it's a fair bet that the line broke at most 15 minutes before the problem manifested itself. I got VERY lucky...no oil pressure problems in the 70K+ miles I've driven the truck since that happened!

Maybe in your case, it was a pinhole leak or a leak at the fitting, which is why you got a small drip...but, if the line fails altogether, I wouldn't expect the same result. Not saying that running a plastic line into the cab is a terrible thing; that's how I'm running the gauge at the moment...but, I would recommend caution and regularly checking the condition of the plastic...

 

[94f450sd]

Run the copper line.ive had way too many of the plastic lines break.the last one pumped a gallon of oil onto my drivers floor of the psd.

GM ran copper oil lines in thier trucks for years.

 

[OLDBULL8]

Lot's of if and's and but's about copper tube. On a diesel engine (speaking about oil pressure line to guage) the line has to be braced for the vibration, you certainly don't want a coil made as someone mentioned, that makes a heavy point and coils are only needed for expansion. Copper line to a pressure guage should be Type K and 1/8" or 3/16" properly braced for vibration. Even the steel injector lines can crack if not braced with clamps.

The "Plastic" line should be Nylon or Vinyl, and treated the same as above.

 

[cheap bronco]

And where do you all mount the fitting for the guage where the tubing attaches to? I mounted my fitting on the drivers side block where the plug right next to the exhaust, and its nylon. Im scared though because of the exhaust heat. On the turbo there is also heat. I was thinking of using copper tubing from the turbo and connecting it to the nylon just before entering the cab. Many of you would ask yourselves why not run copper all way to the guage?, because of the routing the nylon tube. There is no way to bend the copper lines without kinks.

 

[Dieselcrawler]

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in that pic you can see my oil psi gauge on the cowl. I too do not like running pressure into the cab except for air lines. I just used the plastic line it came with, but sleeved it with vacuum hose to protect it. never had an issue with it. hardest part was mounting it to the cowl in a spot the wipers did not block it.

 

[mblaney]

I would use a fuel grade rubber line on the engine. Install a fitting into the block with a small feed hole that will act as a 'snubber' (reduces pulses in the line) but - most important - limits flow if you are worried about that. An orfice of 1/16 would be lots.

If line breakage is a real concern then why not install an electronic gauge with pressure transducer? Might be a little more expensive (Summit has one for $90).