ms040199

I am having a problem with my 87 Porsche 924s' oil system when I drive. When I'm at a full stop and turning, my oil pressure gauge will go from 3psi to almost 0. I replaced the oil pressure sender a few months back and the oil pump seems to be fine as well as I just changed the oil in it so I have no clue what the problem can be.

jeyjey

Those symptoms would fit with a cracked oil pickup tube. (When cornering or stopping the oil sloshes to one side of the pan and uncovers the crack in the tube allowing it to suck in air.)

Tiger03447

Or, it could be badly worn main bearings, or cam bearings..Sounds like a pan pull is in order to check on either the pickup tube and the clearance of the main bearings. Has this problem just manifested itself, and how many miles are on the engine? If the mileage is low, it's probably just the pickup tube. Does it just do it when turning to a single direction or does it do it when stopping in a straight line and sitting a red light for instance, and engine drops to idle?

ms040199

it has manifested itself and it’s got 141k on it but i did a engine rebuild about 4 months ago. The pressure drops when slowing down and turning both directions but will not do it in idle

Tiger03447

That means (usually) that the bearings are in good shape.. If the bearings were bad, when you approached the light, stopped and let it idle, it would drop down to about 10psi/1000rpm or less...Mostly less. So it sounds that a pan drop is still in order for a look-see. Do you run the engine without the balance shafts connected? That can contribute to cracked or broken pickup tubes...or so I've read here..mostly on cars that are raced....just sayin.. Good luck and keep us posted!

harveyf

Those symptoms would fit with a cracked oil pickup tube. (When cornering or stopping the oil sloshes to one side of the pan and uncovers the crack in the tube allowing it to suck in air.)

Sorry Jey Jey but not likely. The spot in the pickup tube that typically cracks is well above the normal level of the oil in the pan. Also, if I read the post correctly, he is at a full stop but turning. Syntax may be mangled but I read he is stopped and simply turning the steering wheel.

As usual, all oil pressure questions need to start with an independent pressure reading. Easier said than done but in this case, it could be the sending unit, the wiring, and/or the gauge on the dash. If it truely occurs at full stop, I would look for the steering gear to be snagging the wire from the sender.

Does the red dash light come on at the same time?

curtisr

From Clark's Garage comes this:The 944's oil pressure should run 4-5 bar at idle when the engine is cold. It will gradually decrease to 2-3 bar at idle as the engine oil warms to normal operating temperature. Once the oil is at normal operating temperature, the oil pressure should indicate around 4 bar at 5,000 rpm. It takes the oil longer to reach its normal operating temperature than the coolant. Therefore, don't be surprised if oil pressure continues to decline after the coolant temperature has stabilized at its normal operating temperature. Occasionally, you may see your oil pressure drop to less than 2 bar. This may happen on very hot days when the car has been driven particularly hard. You should be extremely concerned if the oil pressure dropped to less than 1 bar. This is indicative of an problem with the oil pressure indication or the oiling system itself. Under these circumstances, the car should not be driven until the cause of the low oil pressure indication is determined and corrected.

There are several things that may indicate a problem with the oil pressure indication. If your oil pressure is pegged high (5 bar) or won't indicate less than 4 bar at normal operating temperature, there is likely a problem with the oil pressure sending unit.

Problems with the gauge itself and problems which cause the oil pressure indication to fail low are very rare. A low oil pressure normally indicates an actual problem with the oiling system. One of the problems which may cause low oil pressure is a failed oil pressure relief valve. Although I've never tried it myself, I've read reports from others who have removed the relief valve and turned the engine over to verify that oil comes out the hole for the relief. If oil comes out of the relief hole, this indicates a problem with the relief. If no oil or very little oil comes out, this normally indicates a problem with the pump itself. If a problem with the pump is indicated, check for proper tension on the crankshaft pulley bolt. The crankshaft bolt applies force to a spacer which in turn tensions a gear that drives the oil pump. If the crankshaft bolt is loose the gear will not turn the oil pump. Low or no oil pressure can also be caused by a broken oil pump pickup tube. This is normally caused by excessive vibration when the motor mounts are bad. The oil pan must be removed to replace the tube.

If there is no oil pressure indicated when the car is started, the oil pump may have lost its prime. If this is the case, try removing the oil filter, pour oil down the center hole while rotating the crankshaft in the counter-clockwise to prime the oil pump. Then install a new oil filter. . Then start the car to see if you have oil pressure.

Oil pressure which tracks normally but is lower than normal throughout the indicating range can indicate a leaking oil pressure relief valve or worn main and/or rod bearings.

Clark's Garage Š 1998