red oil light comes on when idle is set to proper RPM

Oil is at proper level, checked many times. Warning light comes on when at a stop and idling or driving on quick tight turns. When RPM's get up there, over 3000 then the light dissapears. Any comments or similar traits noticed would be appreciated. Also, wondering when driving at night, the gauges do not glow very strong. Not really a problem but was wondering if they could be adjusted with a brighter bulb or something???

The oil pressure light may come on at low RPM idle on hot days or after cruising down the freeway at speed and hitting a stop light following an off ramp when the oil is hot (thin). These two cases are fairly normal occurences for stock engines.

However, it is not normal for built engines which usually have higher capacity oil pumps (30mm gears as opposed to stock 26mm gears).

In any case the warning light should go off immediately off-idle, not at over 2,000 RPM.

You may have a bad oil pressure sender; you can buy a new VDO combo sender that has two outputs, one for a gauge (marked G) and the other for the idiot light, and install it to see if your problem goes away. If not, I would remove and check the oil pump for wear on gear end clearance (to the cover) and clearance between gear teeth and the pump casing (specs in the Bentley manual, smaller clearances are better than larger). Other things to check are oil relief valve sticking open (the one next to the flywheel) and the oil pickup tube being loose in the case.

Note that if the engine case has been full-flowed the oil pump outlet hole in the case should also have been plugged - when it is not, some of the oil in the main oil gallery that feeds the crank bearings may bleed off back into the sump; at low RPM this could create a pressure drop that causes the warning light to come on.

To check the pickup tube for looseness, remove the sump bottom plate (necessitates an oil change) and gently try to wiggle the pickup tube around - it should be a tight fit in the case.

The "quick, tight turns" situation is usually solved by adding an aftermarket bolt on sump that increases oil capacity and keeps oil near the pickup tube during cornering.

If none of this seems to solve your problem you may have a porous case casting (oil pressure bleeding off through the casting wall) or main/rod bearing and/or crankshaft issues.

Good luck...

George mentioned the gear and/or pump cover wearing down. This is more likely the problem. It is very common and can easily be fixed. This will cause oil to "blow past" the pump with less pressure than normal. You can cure this by easily removing the pump cover. Then place a sheet of 320-400 wet/dry sandpaper on a piece of glass (for flatness) Pour water over the sandpaper and begin sanding the pump cover until the surface is flat.

Are you running a full flow system? If so, maybe your oil filter is causing the system to back up due to too much impurities. Replacing the filter might do the trick.

If you are experiencing the "porous case" syndrome mentioned by George, which might be the case with the newer aluminum cases from Auto Linea, you may want to replace the block asap before a catastrophic event occurs. After which will entail a costly $$$ expendenture

Glenn, if end clearance is the problem you must remove the pump, make sure the cover surface is smooth, then remove metal EVENLY from the pump housing casting until its surface is the same as the ends of the gears or the gears are about .001" lower than the housing surface. Glass, water, and 600 grit paper should work just fine.

If you make the gears flush with the housing the paper gasket for the cover should provide enough end clearance to keep the gears from binding on it; if not, make a thicker gasket or take a little off the ends of the gears with the glass and emery.

I've never heard of removing material from the pump housing itself, just the pump cover.

$5 says its just a crappy switch that needs replacing

Glenn, the gears are inside the housing (recessed); if there is too much space between the housing and the cover you have to remove metal from the surface of the housing to reduce any "slop" between gears and cover (move the cover closer to the gears). Draw a cross-sectional picture of the housing, gears, and cover and examine it...

I had the same problem; it turned out to be a sticking oil bypass valve.

come on dave, did you fix it?

Get an oil pressure gauge and see what's going on. Also make sure your using thick enough oil, 10-30? 20-50? straight 30? or 40?. If you getting a low oil preesurte reading at idle when using 10w30 it might be time to go to a larger pump. I've noticed a 10 psi diff. when running 10w-30 opposed to 20w 50.

J-P

5 bucks says the oil is getting too hot and dropping off......or the oil weight is too thin for the application.

Do you have a temp gauge? what weight oil are you using?

come on, it's worth 5 bucks, whats wrong?

David.
Did you ever get to the bottom of the problem? Or are you stuck in the garage trying to fix it? Let us know.
DS.

Sorry for not writing sooner, been traveling and finally home and catching up...
I am running 30 wt. oil on a engine that has 2000 miles. Car runs and sounds strong. I will have mechanic check what was all mentioned when I service in another 1000 miles. I think it is due to thining when I run long and hard.