to those with aux water temp gauge - cluster vs aux readings??

[Sh3rpak!ng]

Only downside is now I'm very aware of how the engine is behaving. I'm finding that the stock 5w40 at cold start temps (+5c ambient) is about 50-60psi at idle, it drops progressively and hovers around 12psi idle when the oil gets hot (100 celsius). In stop and go traffic my pressure light flickers off and on somewhat frequently but I've replaced the oem switch with a double pole VDO that has a 10psi warning contact. I seem to never drop below 8-9 psi by the gauge reading.

I wouldn't be worried about those hot idling pressures... pretty normal for an *old* S/M5X with many *worn* surfaces. What's most important is your oil pressure under power. How many miles on it?

[JRKOUPE]

yup..

hot idle can be like 8-12 ish

kinda common...



as asked, miles?

[Varinn]

Engine was recently rebuilt by a highly reputable local machine shop to stock specs (hone, rings, bearings, valves). I'm at about 6,000km since the rebuild. Did not replace the pump which has roughly 150,000km. Nut is secured. Pressure hits about 55-60psi above ~3500rpm when hot.

My new gauges actually led me to finding a voltage issue. Started getting fluctuations after a track day this weekend with it dropping to 12.5 at times from 14. Intermittent fault with no cel and barely visible battery light flicker at some points. Suspected brushes but found both bearings very loose which killed the brushes from shaft wobble. On pulling the belt to get it out also noted Graf pump bearings had play and trickled coolant when wiggled. Only 30,000km on both of these! Talk about piss poor lifespan... glad I noticed the voltage dips early, either of these could have left me stranded.

Should I swap my 80a to a 140 while I'm at it? Car is fully loaded but stock electrically (16" pusher fan, heated seats, mild stereo never cranked, no ac, deleting ps this week).

[Sh3rpak!ng]

Engine was recently rebuilt by a highly reputable local machine shop to stock specs (hone, rings, bearings, valves). I'm at about 6,000km since the rebuild. Did not replace the pump which has roughly 150,000km. Nut is secured. Pressure hits about 55-60psi above ~3500rpm when hot.

My new gauges actually led me to finding a voltage issue. Started getting fluctuations after a track day this weekend with it dropping to 12.5 at times from 14. Intermittent fault with no cel and barely visible battery light flicker at some points. Suspected brushes but found both bearings very loose which killed the brushes from shaft wobble. On pulling the belt to get it out also noted Graf pump bearings had play and trickled coolant when wiggled. Only 30,000km on both of these! Talk about piss poor lifespan... glad I noticed the voltage dips early, either of these could have left me stranded.

Should I swap my 80a to a 140 while I'm at it? Car is fully loaded but stock electrically (16" pusher fan, heated seats, mild stereo never cranked, no ac, deleting ps this week).

Nah, no need for the 140. And my hot idle oil pressure is about the same after a full rebuild. I changed to a better condition pump after worrying about low idle oil pressure and finding some scoring in mine, it helped a bit, but its really nbd as long as pressure under load is good.

[Jaker]

I'm running 5W40 Driven DT40 synthetic oil, and my lowest hot idle pressure is about 16-17psi. My pump is the Z3 aluminum block single Vanos pump (it's a little different externally, but the internals are the same). You could also bump up your idle a bit. Mine's set at 900 rpm to stave off the Getrag gear rattle.

I rebuilt the motor about 20,000 miles ago, and it gets beat on pretty hard - 7,800 rev limit in 1st and 2nd. I think if you're concerned about your hot idle pressures, and not already using a good synthetic, it might help.