I just rebilt my 2.3L and is has low oil pressure when it heats up?

Oil light comes on when idling because the oil pressure is low or restricted. This could be due to a clogged oil filter or oil pan strainer.there are several other reasons, these would require more information.Has the car had an oil change?What is the mileage of the vehicle?

Scan the computer , it may be faulty.

The engine bearing clearances expand with heat which, if excessive, will lower the oil pressure. The spring in the pressure regulator in the oil pump will cause the pressure to drop for the same reason. A partially plugged oil intake screen will work in conjunction with the oil pump to cause it too.

oil pressure will drop for a few reasons:low oil leveldefective oil pump

First check the oil level and condition. Have your trucks oil pressure actually checked with a gage. It should be at least 42p.s.i. to 55p.s.i. The knocking noise is probably related to low oil pressure. Depending on the type of knock it could be crank shaft bearings, piston wrist pins, rod bearings, cam bearings or noisy lifters. All a result from low oil or pressure. 3 possible causes, are low oil level and pressure, lack of oil changes and viscosity of oil breaks down to where it can't lubricate or dissipate heat and coolant getting into oil, reduces pressure and prematurely wears down bearings. Have it properly diagnosed before you seize your engine solid.

Low oil level can cause an engine to run hot but the pressure must be extremely now for that to cause a rise in operating temperature. Naturally, if the temperature is high on the guage, the engine is already overheating, and there are a multitude of reasons why an engine could overheat, from silly things like low tyre pressures to low coolant levels and water leaks. If you like, come back with some more specific information and lets see if we can put a finger on your problem.

Do not assume that the low oil pressure warning is a false one or that you only have a faulty oil pressure sensor. Your engine may in fact be running with low oil pressure once the oil heats up and thins out. 8-10 miles of running is enough to get the oil hot. It is significant that you only get the low oil pressure warning once the engine oil is warmed up.

If the oil pressure in the engine is low, engine lubrication will be impaired and the engine can be badly damaged so you need to run an engine oil pressure check.

1. How long has it been since you have changed the oil in the engine? If it has not been changed in the past 6 months then change it and change the oil filter at the same time. You must only use the oil specified by VW for that particular engine.

2. When new oil is heated it thins. If it is old and contaminated it will be even thinner when warm. You will get less oil pressure when the oil is thin and hot and more oil pressure when it is thick and cold. Fresh new oil is a little thicker as it has not been diluted with petrol and other contaminants.
Oil pressure also varies with engine speed (RPM). At idle or low engine RPM the oil pressure is lower.

3. OIL PRESSURE CHECK
After the oil is changed the car needs to be run to check if the oil pressure warning still appears. (I suspect that it probably will). If it does appear then an independent oil pressure gauge needs to be connected up to the lubrication system in the car to check the engine oil pressure. This is best done when the engine oil is hot because this is when you are getting the low pressure warning. Any competent mechanic will be able to do this. ( The useless ones will not). The oil pressure can then be properly checked on the gauge at various engine RPM. If there is a low oil pressure reading from the gauge then there could be a problem with the oil pump, the oil pick up or the oil pressure relief valve in the engine.

4. You mentioned that you see the oil pressure warning disappears once you accelerate. I suggest this is only occurring because with an increase in engine speed (higher RPM) the oil pump speed is increasing and the low oil pressure problem is being overcome temporarily. However as soon as the engine RPM drops the oil warning will appear again which means the engine is running with below minimum oil pressure at that RPM.

Even when you get no warning, the oil pressure in the engine could still be running significantly below the optimum level.


5. It is possible that the oil pressure is fine and that the problem is an electrical gremlin as these cars suffer from a variety of electrical faults. However from what you have described I think there is a problem with low oil pressure in the engine and until it is properly checked it is unwise to assume that you are just getting false oil pressure warnings.

I hope this helps.

Sounds like you have an internal engine problem. the only way to be sure is to check the oil pressure with an external gauge.

You should replace your oil pressure sensor its cheap and easy to do...

Steve

With the car warmed up, oil pressure should be 1.5 kg/cm^2 @ 800 rpm. If your not getting that much, you may want to get an oil pressure gauge (mechanics type) to check it. Using this type of gauge will give you an accurate reading. The stock gauge may not be very accurate, especially if the sending unit is old.