Don't take this as an insult, but are you sure it's the oil pressure (red)
and not the oil level lamp (yellow)? In my '91 525i it turns on (well, the
CC pings) after hard driving if there's just under half or about a third
of oil between the marks. If the sensor is at the front it might the
On a former 735i, if the oil level was low (but above the lower mark) and
the car was worked hard (e.g. up a big hill) then the oil level warning
would sometimes if one suddenly eased off (leaving a lot of oil in the head
& galleries). Never did it before starting except the time the garage
didn't tighten up the filter properly and some ran out.
How many miles on the car. Chances are the bearing clearances and the
oil pump are not going to be as tight as they once were. The
combination of larger clearances and oil thinned from the heat of
pulling a trailer could trigger the oil pressure lamp.
Did the light go out as you reved the engine on a hill?
You should have a BMW dealer put a real pressure guage on the engine
and check it out.
No, only when I got the car level and restarted the engine. I'll do an
oil change tomorrow. According to the lights on the dash it's about
time, and I've also used two bottles of injection cleaner in the last
couple of tanks.
If the sump shows full on the level and the problem only appears when
on an incline then you need to have it checked out soon. It may be
nothing, but the dealer should be able to replicate the low pressure
indication with a real pressure meter. The dealer will also be able to
go through a complete diagnosis are rule out reasons for the low
pressure light to come on.
Sorry if I am repeat, but I dont have the time to read this entire
The M30 engine is almost indestructable, however, like everything there
is an Achilles heel. Lets start with the most infamous culprit- the oil
spray bar banjo bolt. If it comes lose the oil pressure will drop and
spin the bearings or worse.
Another is the plastic check valves located inside of the oil filter
housing. Symptom of an ill check valve (check the banjo bolt first) -
oil pressure light takes several seconds to extinguish. The check valve
allows the oil to bleed back into the oil pan and it takes several
seconds for the pump to re-prime and fill the oil galleys again.
The M30 is a truly wonderful engine yet it will still require your
I checked the banjo bolt when I adjusted the valves and it seemed tight.
I think I might have this problem. When I did the oil change and removed
the old filter the filter housing was dry, except for a little oil at
the bottom. I thought it was strange because I read that oil would
splash out when removing the cover, but if the valve is broken that
might explain it. The oil light does take a couple of seconds to
extinguish, and sometimes flicker, after startup, but I figured that was
normal on such an old car.
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