LOW OIL PRESSURE LIGHT, STOP ENGINE, CHECK OIL LEVEL when engine is warm X5 V8 4.4i

[subieworx]

It's a bearing clearance issue. As the car reaches temp and the oil heats up the viscosity lowers causing lower pressure. At idle the pssure is low enough to trip the light. Over time, and probably not much, you will have issues with rod and main bearings.

[pasken]

So what should I do with it? Rebuilding engine is not an option... Should I try 20W50 oil and oem filter? Do you think it would help? Should I try some oil additive before dumping money in another oil change?

[civdiv99]

It's a 12+ yr old car with probable oil pressure issues. If it was me I'd monitor the pressure with an after market gauge since that'd answer most of your questions pretty quickly.

Don't expect dealer to be able to fix anything, but they'll be more than happy to suggest replacement items, and you won't like the cost.

The temps you see are indeed what BMW has for the intended operating temp. And while lowering the temps may be desirable for a lot of reasons, it isn't a fix for your situation in any case. IF your internal clearances are excessive, which is quite probable, then what you have is a very worn engine on borrowed time.

You can try some high viscosity oils, and that may get you by for a little while. In the meantime, drive it like you're 78 and wondering where your Volvo went......

[pasken]

Do you think I can try Lucas Pure Synthetic Oil Stabilizer? or it's better to use some other additive? Or change oil again this time to 20W50? Seems like I ll need to trade it in in the next couple months...

[JCL]

What do you hope to gain with an additive? It won't fix anything. It may make the oil thick enough to sell the vehicle quickly to an unsuspecting buyer.

Oil pressure rises with rpm. At low rpm you naturally have low pressure and the engine condition is making it worse. Fix it, live with it, or sell it.

[pasken]

Originally Posted by JCL

What do you hope to gain with an additive? It won't fix anything.

I assume if I switch to higher viscosity oil like 20w50 might give enough pressure to not trigger oil light, which in turn would mean slightly better operating conditions for the engine and hopefully slightly prolonged life. Am I correct or no?
By thickening my current oil (5w30) with additive I should be able to achieve higher viscosity oil too. Am I correct or no?
How long it can last in current condition? - are you talking about few hundred miles or more like 3-4k miles or 10k miles?

[JCL]

Originally Posted by pasken

I assume if I switch to higher viscosity oil like 20w50 might give enough pressure to not trigger oil light, which in turn would mean slightly better operating conditions for the engine and hopefully slightly prolonged life. Am I correct or no?
By thickening my current oil (5w30) with additive I should be able to achieve higher viscosity oil too. Am I correct or no?
How long it can last in current condition? - are you talking about few hundred miles or more like 3-4k miles or 10k miles?

Yes, higher viscosity oil may stop the light from coming on. That doesn't mean better operating conditions for the engine, but rather worse conditions. The light is not the problem, it is an indicator of a different problem, in this case likely worn bearings. Putting thicker oil in will cause accelerated wear when cold, so that isn't advisable. The only reason to put thicker oil in is if you want to mask the problem, sell it quickly, and dump it on an unsuspecting purchaser. Some would call that fraud, unless you disclosed the problem up front.

Yes, an additive may do the same thing, but it could have other problems associated with its use, due to compatibility with other parts inside your engine. Skip it.

The light is on when the engine is idling slowly. Live with it. When the engine speeds up it is apparently enough to turn the light off. If you want to confirm it, get a shop to hook up a separate diagnostic oil pressure gauge, and get the readings at idle and above idle. That will confirm the diagnosis, but if it is what we think it is, there is no easy fix. If oil pressure is also low above idle, it could be a worn oil pump, which is a little cheaper than bearings.

Some engines have run for years with low oil pressure at idle. There is no way to tell how long it will go, without tearing it down to see inside.