Educate me a bit on oil pressure readings. It's my understanding that if there is oil in the engine, even if at a dangerously low level, the pressure will read correctly (assuming the sender is working right). Is that correct? If so, what is the gage going to tell you that the idiot light won't? Maybe that if the pressure is trending up or down over time that something else is going wrong? Every time I've seen that it's been the sender itself though.
When the oil gets dangerously low the pickup will suck air from time to time and the pressure will vary from air to oil
with the lifters protesting when they get a gulp of that air. Also the lower the oil level is the HOTTER the oil will get as it is reused more often and doesn't have a chance to lose it's temperature before reentering the engine.
The lights were tried many times in the past. Buyers of the vehicles proved to be more conscious of the readings than the lights would provide.. So back to the gauges we went. Most modern gauges are simply glorified lights! When 12 pounds or so are reached the needle goes to the MIDDLE of the gauge. Then when the pressure drops to 12 pounds or less the needle goes to the bottom..
For most engines 20 pounds of oil pressure will work as well as 40 pounds under all but the most demanding of circumstances.
So that said, the manufactures of the senders and gauges are rather reckless in having EXACT measurements. Although your TWO senders have sent different signals to the gauge, I'm sure the pressure hasn't changed and doubt if either are CORRECT!.
For my own use I'd just as soon have a light...and even with a bell would be Ok too.
Hell! My new pickup even tells me when I'm a quart low.. It hasn't told me yet but someday it will.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />
