I replaced the sending oil unit with oil, temp and voltage gauge and the oil pressure sems to reading low about 2 - 5 lbs when idling and when driving it goes to about 20 or so.....is this oil pump need changing.....

 

The idle pressure is to low. I recomend you try another manual oil guage before you consider tearing the engine down. New guages have been bad right out of the box before. Let us know what you find out. Don't drive you car until you find out what the problem is.

 

Welcome to CO ridge. Hope you find the solution to your low oil pressure dilemna.

 

The pump screen could be clogged depending on the age of the engine. The original timing sets would deteriorate and the plastic get sucked up by the pump.

You could have bearing wear causing large tolerances giving low pressure.

There are a number of things that can cause this.

I have ever heard of the by-pass being stuck open causing low oil pressure.

You just never know until you open her up.

 

i had this happen to me a wile ago. so went got the real gauge to make sure it was low. so i buy a new high flow oil pump and crank bearings and connecting rod bearings. i just ended up putting the oil pump in the bearings where good if your not realy hearing any rattling or odd engine noises then their probably not that bad, i guess. but the oil pump helped a ton the screen wasint too clouged. it looked like on my old oil pump the gaskit in the pump that held the turbins togeter was brokin and leeking oil back out in to the pan