Hello,

Now that I am putting some miles on the rebuilt engine in my Charger (almost 2500 now), I noticed that the factory gauge has gradually read lower than it did before. I know some of this is normal as the engine wears in. However, my oil pressure gauge has read as low as midway between the bottom and first mark when idling at 800rpm, fully warm on a hot day. Cruising around 2500-300 rpm puts it straight up when its hot.


I don't hear any ticking from lifters but I wanted to see how normal this is. FWIW the gauges were rebuilt by Intrument Specialties around 5 years ago. I run 10w30 oil.

Thanks!

Smartest cheapest thing to do is check pressure with a mechanical gauge.

Yeah I will likely when it cools. Just wanted a quick answer.

there is no quick answer to oil pressure questions.

the oil pressure should not drop "as things wear in" and if does it's not a good sign. I wouldn't be too concerned about it at this point as many things can cause the readings to vary with an electrical factory gauge. The gauge itself, any connection problems, charging voltage, sending unit to name a few.
Engine temperature, ambient temperature, oil type, viscosity also can have an effect. Get a mechanical gauge on it and keep an eye on it.

Did you change the gauge voltage limiter to a electronic one? Some people report this happens sometimes. Check how many volts is getting to the gauge 9 hard to do)

Yes gauges are converted to the solid state VR. I doubt that's the issue as the temp and fuel gauge are pretty accurate.

Oil PSI is fine. First pic is cold 75 psi, second pic is hot, in gear, idling 720RPM still with 45 psi.

Any way to bench test a sending unit?

Sure, you need an ohmmeter, an air pressure regulator, an air pressure gauge and a source of 100 psig air. Then just check the three operating points.

Thank you. I am guessing my unit is bad as it reads open between the body and the sending unit stud. Thank God it's not the engine

No doubt. Solid numbers with the mechanical gauge.

Quick update. I got a new sender (Airtex/Wells) and we are good. Oil gauge reads 7/8ths to the top while cold and just below middle when hot.