Normal oil pressure for a 3 litre M54?

Pondy

Pondy

Muppet
 At the summit of the picturesque fens
Does anyone know what oil pressure is normal for a healthy 3 litre M54 engine?
I now have an oil pressure gauge and it always seems very high (although I don't know what it should be).
On a cold start (20c ambient) my gauge reads around 70psi. It gradually decreases if idling to around 30psi when the oil is up to temperature.
When driving my gauge is always showing over 40psi (which is the middle of the gauge) and can easily show 60psi at around 3,000rpm.

The other question is what grade of oil should a healthy 55k miles M54 use? Mine has been filled with 5w40. Is this too thick? If it is that could maybe explain my high oil pressure, if it is high?

Any info/ advice much appreciated.
 
If you get 30psi at warm idle, that's great.
I run 5W-40 in my M54 (20K miles), and it works well. I'd say those pressures you listed at various rpm's are perfect.
No worries there! 😉
 
Those pressures sound fine. several comments on the E46 fanatics and Bimmer forums indicating around 4 bar (58psi) is correct with some revs on. Other engines I have - A series for example are all the same area. Low pressure at idle - 10psi or less when hot might indicate worn bearings so yours sounds good.
 
The spec for the M54 will be anything from 0w30 to 5w40, probably even a 10w oil. It was designed in the 90s when pretty well everything ran on 10w40 semi-synth (that was standard spec for M50 & M52s.) The LL01/04 (possibly LL-99 too) norm became fully synth 5w30.

Upshot of all this is that the correct spec is: "Has it got oil in?"
 
Yes 5w30 fully synth is what the last place I had a service at used, an indy specialising in German cars, mostly BMW it seems. :thumbsup:
 
I would have suggested that in the UK, with an engine of that low mileage, stick to the original 5W-30, but 5W-40 won't hurt.
Most people seem to swap to that once the engine gets to be a much higher mileage.
FWIW, I put 5W-40 in wifey's 2.5i last time around and immediately saw codes for mechanical stiffness in the vanos solenoids/shuttle valves. Reverted to 5W-30 and it's all fine again. Could have been coincidence I guess??
 
Ran my 320d to 276k miles on the cheapest 5w-30 that met LL-04. What is this "higher mileage" you speak of? ;)

I rebuilt a Smart car engine a couple of years ago (2002 600cc turbo) and, again being very 90s, it ran 10w40. Compared to the 5w30 I've got used to over the last 20 years, it flowed like cold syrup. I couldn't believe that this, and thicker ones like 15w50, were once standard spec. I think this comes from synthetics being better at shear resistance rather than relying on bulky oil to keep metal bits infintessimally apart.

The latest trend is 0w10[1] oils to lower emissions further by eliminating friction but, owing to it having the consistency of warm pee, it's eliminating engines instead.

[1] I just googled this to check I wasn't dreaming and, apparently, 0w5 is a thing :eek:
 
MikeyH said:
I'm sure when I started driving 'back in the day' it was something like 20w50? 🤔
Click to expand...
Castrol GTX was all the rage, but I put Duckhams in my old bangers as it was reckoned to be a bit thicker. :LOL:
 
I has cold engine about 3.6-4bar and oiltemp ->70 its about 2bar.
When i rev engine its about 4bar. Oil is 5w-50

But my engine is rebuild under 2000km ago, with forced parts etc etc m54b30
 
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