Oil line for gauge

[Grant Bowker]

Originally Posted by Bruce Parker

Next question...do you bleed the line or does the oil find its way to the gauge despite the air in the line?

Does it matter? The relative densities should keep the oil below any air. As the engine oil develops pressure, any air above it will develop an equal pressure and indicate the pressure on the gauge.


Regarding "proper" size, most (all?) civilian pattern Chevrolet gauges I've seen used a small/capillary line. I'm sure I've seen the round gauges with larger (3/16" or 1/4") OD line (the fitting on the back of your gauge may help on sizing) but I'm not sure if I remember capillary line being used as well.
Parts book C15A-04 section 1.519 lists 1/8" tubing (tubing is normally specified by OD as opposed to pipe which is by nominal ID) for use as "Oil Pressure Gauge Pipe" which is a bit larger than the capillary tube I'm thinking of.