Weird Oil Pressure Issue

[EddyB]

1990 Ls400 180k miles. Recently changed my oil and started having oil pressure issues.

Once the car is warm, the low oil/ low oil pressure light comes on. Before it had only came on if I was a little past the oil change and was low, but only if I was going fast. This time it came on right after my oil change. I noticed that when I take a sharp turn, mainly left, when I accelerate, when my car is driving on an angled road and when it hasn’t warmed up yet, the light is/turns off.

The light also turns off when I’m riding on a bumpy road. I’ve replaced the oil pressure sensor and tried different levels of oil. As well as an old school ATF engine flush and topping off with 5w40.

Higher rpm’s in neutral don’t change anything. Havnt had the chance of checking the actual oil pressure with a tool. Im suspecting a failed oil pressure valve. There is a tiny leak somewhere, but not a enough to leak a stain on the concrete.

What can of worms am I getting into replacing the oil pressure valve?

I suspect removing much of the lower end just to reach it.

 

[ivan129]

The way you describe lossing oil pressure when turning suggests the engine is low on oil level. The oil pickup is exposed to air, ie. not in the oil. I assume you have checked you have sufficient oil in the pan. A new filter and oil fill will take about 5.5 litres, or 5.82 quarts. I really don't like th idea of an ATF flush. There is a real chance of damaging bearings if driven. I would suggest using a fixed weight oil like a 30 weight and adding a 1/2 a bottle (quart) on Lucus Heavy duty Engine oil sabiliser. That will fix yout problem for sure. Worked fine on my Audi that did the cam bridge bearings (it would loose oil pressure when idling, when hot, before the magic treatment). So well that the dealer didn't pick it when I traded the car.
Good luck.