My truck loses oil pressure once at temp?

Question

Its a 92 Chevy Silverado with the 4.3 Liter V-6. My dad thinks that its the oil pump going bad. But i asked a mechanic i take my cars to and he said as long as the oil pressure doesnt drop below 5 psi its just that im losing viscosity. So i changed the oil and it still does it. I dunno who to believe

Answer 1

Do you have an oil pressure gauge in your truck? It's normal to lose a bit of pressure once the engine warms up. If the engine has a lot of miles, the bearings could be worn causing some loss of oil pressure. The oil pressure sending unit may also be old and not reading right. Generally if it's not knocking or rattling heavily when you notice the low pressure, them you don't have to worry. I had a 94 Astro with the 4.3, the gauge always showed quite low pressure at idle, it never hurt anything.

Answer 2

Your bearings are worn. The oil is pumped thru the crank shaft first and when the engine is cold the oil is thicker and doesn't flow as easy as when it is hot so when the oil is hot going thru worn bearings most of the oil runs out of the crank shaft  past the bearings and by the time it gets to the sending unit the pressure is low. It may run a long time with low pressure and it could take a c**p tomorrow. If it gets to knocking turn it off.  

Answer 3

when you loose oil pressure does the engine start ticking and making noise ?  your mechanic is correct to a point....but no pressure no viscosity....but if your engines not making abnormal noise when this happens then try a mechanical Gage and see if this gage reads normal....but it may be easier to buy a new sending unit for the Gage...

Answer 4

oil pressure sending unit is bad.