Oil Pressure

I have a 1987 silverado that I just put a mechanical oil pressure gauge in. The problem that Im having is that when I first start it the oil pressure is
at 40. The more it warms up the more the pressure drops.Eventually it will drop to almost 0. My question is what causes this and how do I fix it?
--
Posted at author's request, using moderated http://www.AutoBoardz.com interface
Thread archive: http://www.AutoBoardz.com/Oil-Pressure-ftopict247888.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What engine and how many miles?
Al
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Buddha wrote:

Oil pressure drop while the engine warms up is normal. The oil is getting thinner and easier to pump as it heats up. However 0 is NOT a good number on an engine. How many miles are on the engine and what oil are you using.
On a small block you would like to see about 15-20PSI at idle with pressure increasing by 10PSI every 1000 rpm or so.
--
Steve W.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Eventually it

A friend of mine tried an unconventional fix that worked on his Silverado. He took the special sand from an hourglass, poured it into the engine oil and then the pressure stayed at normal level, even when the engine is running hot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Stupid is as Stupid does
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

WOW, Stupid is right. I've NEVER heard that one before. Besides most of that so called Special sand would have been filtered out before it even went into the Engine I would think. Other then being Dumped on top of the rockers and other things on the top of the head before draining down into the oil pan to be sucked up by the pump and to the filter before entering into the rest of the engine.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The first thing Id want to do is verify the results with another guage.
Why did you replace the guage in the first place? Was the idiot light coming on before the replacement?
If another guage verifies your results then you probably need to pull the crank and do a bottom end job/new bearings/turn crank. With an engine as old as yours, and I suspect a lot of miles, you may want to just go ahead and get a crate engine, because once you get that far into an engine for a "fix" you may as well, in most cases, rebuild the entire engine. Either way you are probably looking at an expensive fix. If perhaps the engine isnt using oil/plugs burning clean/ you may get away with just a bottom end job for a good long while, thing is by the time the crank bearings need to be replaced, the rest of the engine is just as worn and a quick fix of one symptom is followed by the need for another.
You may prolong the bottom end job by using a heavier guage oil and perhaps use some STP or other engine oil enhancement. No guarantees there, but it can and does help in some cases. The guy who picks up my trash has an old Ford POS pick up truck, and the oil pressure guage reads zero on it too, still drives it every day...engines are like tires....you never know when they are going to go.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.