Oil pressure warning light

My oil pressure warning light has been coming on at idle RPM, then shuts off when the RPM's exceed 1,000; as the engine gets hotter, the warning light sometimes won't go off until the RPM's reach ~1,400.

The engine is a 1776, with dual Weber 40's, a Melling HD oil pump -8mm to 70, external oil cooler/filter.

Any guesses on what's going on here would be appreciated.

Thanks

Dave


(Message Edited 1/21/2003 12:27:52 AM)

Try a new sending unit first.

Need more info - has it always been like that or is it a recent development? Yeah, try a new sender first.

George,

Just picked up the car last Thur., and has been acting that way from the start.
Also noticed a small oil leak where the hoses connect to the oil filter - not dripping oil, but still not a perfect seal.

Dave

David, more info please? Is this a new car and engine or did you buy a used car? If it's used, what size engine and how many miles on it? Does it seem to run hot? The remote filter lines on my car leaked, too. Definitely try a new sender; get a VDO dual sender and hook up the idiot light for normal driving - order a VDO oil pressure gauge and you can connect it to the G terminal on the dual sender along with a hot wire and ground (terminals on the alternator with alligator clips) and check your oil pressure at hot idle and 3,000 RPM. Pressure at 1,000 RPM hot idle should be 20 to 25 psi, and probably close to 50 psi at 3,000 RPM. You can hook up the gauge whenever you want to check your oil pressure, then disconnect it.

George, it's a '96 IM Roadster with ~4,900 miles on it.
The engine is a 1776 (see listing of the major engine parts below). It dosen't seem to run hot at all; the temp needle rarely goes beyond the half way mark.
Installed new sender, and again, when the engine is first started up the oil pressure light doesn't come on, but as the engine heats up, the light comes on (when I come to a stop light at idle); if I increase the RPM's it goes off.

engine block $599.99
counterweighted 69mm crankshaft $599
remanufactured connecting rod $63.96
main bearings, .010 $29.99
rod bearings, .010 $16.91
double thrust cam bearings set $15.99
piston & cyl. kit 90.5 x 69 CIMA $230.37
flywheel, lightened & balanced $79.99
042 racing head 40 x 35.5 $399.98
Euromax exhaust w/ dual muffler $114.99
heat exchanger 63-74 $69.99
1700lb scat pressure plate $89.99
cushion grip clutch disc 200mm $60.98
12v alternator kit type 1 $185.99
dual 40 webers $699.99
melling HD oil pump 9mm to 70 $48.99
racing "quick cooler" kit $60.98
hi performance pushrods 13-1600 $33.98
spring loaded p/r tubes $67.98
teflon wrist pins $14.99
solid pulley , stock size $29.98
silicone ignition wire $13.98
12v Bosch blue coil $19.99

OK. Years ago my '67 VW owners manual said that might happen, e.g., engine hot and light comes on at idle.

First, what is your idle speed? If its 800 RPM setting it up to 1,000 RPM may solve the problem and won't hurt anything.

If a 1,000 RPM idle speed doesn't turn the light off, buy a new blueprinted Schadek 30mm gear oil pump with O-ring from Berg and replace your old pump with it.

Also, next time you change your oil and have the round plate off the sump try to wigle the oil pickup tube with your finger; it should be a tight fit in the case end. If the tube itself is loose the pump may be sucking a little air through the tube/case joint which aerates the oil and causes lower oil pressure.

Another thing you can check is that both oil bypass valves (in a dual bypass case, otherwise there is only one valve) are not sticking or scored/scratched.

Before you fix anything, you need make sure you have a problem.
The first step is to install an oil pressure guage.
Even if you just screw a mechanical guage into the engine case,(temporarily) you'll at least have an idea of what the oil pressure really is.

Greg B

your problem comming over 150 000 Km = 100,000 Miles Your Crankschaft hat to match diferenz, oil press going by lost. yes !

David, didn't this turn out to be a sticking case relief valve?

Yes, it was a sticking valve.
Oil pressure is fine now.
Thanks to all who responded.

Dave