QuestionI have a 1986 Chevy K10 pickup. What should the oil pressure gauge read during operation. I just installed a new gauge because I think I had a short in the wiring because the oil light was always on and I could not find anything that would cause that problem.
AnswerDo you mean you installed a guage in the dash? I am guessing that is the case. Your reading should be between 30-70 psi. Higher when cold. Synthetic oil could read lower when warm. Normal pressure when crusing 45 mph should be 40-60 on a good motor with stock parts.
Pressure can tell you things. If you read too high, you may have spun a bearing. If you read too low you have worn bearings. You could also have bad drive gear on pump, or worn pump, or bad relief valve in pump. If your problem is not one of these mechanical things, it could be a sending unit or light switch.
On motors with lights, this would be a switch. On motors with guage, this would be an actual sending unit. The sending unit tells the guage what to read. If the switch is grounded, it would cause the light to come on. If the sending unit is faulty, the light and guage will think the motor has weak pressure.
These switches and sending units are found on the side of the block in an oil journal, on the back of cylinder heads, near the oil filter. Rarely found on top of motor. Sometimes you have both if you have both a light and a guage.
Hope this helps.
C J S
