I installed an autometer mechanical oil pressure gauge about 2K miles ago. During the install I used the supplied plastic 1/8” line. Only problem was that it wasn’t long enough. It was only 6’ in length. I needed about eight feet. So I went to the local auto shop and picked up an extra “sensor kit” which consisted of some compression fittings and another six feet of plastic line. Well as it was getting to be the end of the day, I just went ahead and used some compression fitting to join the two plastic pieces of line together and cut the extra off. I put in some conventional 5-30 oil and a standard purelator oil filter in as I was going to change it in about 2K miles anyway, (just so I can stay on my every five thousand mile interval)
This weekend I changed my oil again. Mobil one 5-30 and a pure one filter. I never liked the way I did the plastic line, so before I started I went to a home store and bought ten feet of 1/8” copper tubing. After installing this line with the synthetic oil. I noticed that the response of the gauge was not as fast as when the plastic was on. The inside diameter of the plastic line was larger than the copper and I think that might be the cause of it. Another thing I noticed was the oil pressure readings are a little lower. With the plastic tubing, when the engine was cold the maximum oil pressure reading would be about 85-90 psi. when shifting around 2000 rpm. Now it reads about 75-80 psi. under the same conditions.
Just some comments and observations, I would like to here what some of you guys used when you installed an oil pressure gauge.
Jes

 

Talked about this situation with a buddy at work that build his own engines to ask him what he uses and he said that he would use plastic only. The reason he would not use something like a copper is that he was worried that it might suffer fatigue and leak due to the vibration of the engine.
So it seems like I am going to have to replace this line again. Its ok i guess I didn't like the response of the copper line anyways. I hope I don't lose too much oil dropping the line out.
Jes

 

Seems like the copper would be better than plastic as plastic would melt from heat and crack and so on.

 

HI!... Why don't you run -3 stainless steel braided line for your oil pressure guage? This is what I have run on ALL my vehicles with mechanical guages and NEVER had a problem with them. In my opinion I would never use the neoprene (PLASTIC) line tubing that comes with the guage. I've had several of them fail because after time they crack and or get hit by something while working under the hood.

 

I think I'm going to install mine with barbed hose adapters on the meter and the oil port. Then connect the the adapters with braided SS hose and clamps.

One question: Do I need to bleed the hose to the gauge for trapped air? That might be a cause of erroneous readings on the gauge. If I do bleed it, what prevents air from finding it's way back up the hose?

 

TTT

 

No need to bleed (50 PSI of air is the same as 50 PSI of oil).

Always wrap your own coil of tubing as vibration isolation (look at brake lines at the master cylinder for examples) for any piece of tubing that might be subjected to flexing/tugging/compression.

 

Y2K 7700 4x4,

Thanks for the answer to the bleed question and for the tip on coiling the tubing - will do.