Apparently on date Wed, 30 Nov 2005 17:07:03 -0000, "Doki"
said:
"Carl Gibbs" wrote in message
...
"Doki" wrote in message
...
The Golf's playing up. Must be because I've polished it.
When the oil's warmed up to 80 odd or so, the oil pressure lamp comes on
if the engine's allowed to idle. Rev it at all, and it goes back off.
I've previously had the buzzer come on a couple of times during normal
driving, (ie, above a couple of thousand revs, oil not stinking hot and
not cornering like a loon) but it's always gone off after a second. Oil
level is fine.
Pointers on whether this sounds like oil pump, dodgy electronics or the
bottom end of the engine dying would be nice.
Have you changed the oil recently?
Yep. Not myself. My dad decided to change the oil for the stuff he puts in
his jag without telling me to see if it made any difference to the buzzing
that happened before. ****ing hell. That's like a sentence written by Peter
of cinquecento fame...
Could be the pump, could be the pickup - have you given the sump a whack
recently? As Carl said it could just be a dodgy sensor. I would just go
for trial and error until it was fixed, but someone with a bit more
knowledge may be able to help!
Sump is new and unbanged.
As for the buzzer - wouldnt worry about it. My main aim when I used to
borrow my sisters Polo was to get that buzzer going. The little thing
just kept going (with knackered head gasket) 
I reckon it's worthwhile getting a gauge as it seems the sensing system can
play up.
I got one for fifteen quid in the summer, including the hose and connector.
It just plugs in where the sender goes. You get a more realistic idea of what's
really happening with a gauge.
Be aware that these things are only measuring oil pressure above the pump
itself. If there is a lot of wear in the main bearings, oil will pour through
and while the pump can maintain pressure at the gauge, rather less is making it
all the way up to the overhead cam, etc.
Whacking up a grade of oil works to compensate for wear in both main bearings
and pump rotor vanes so it you want a cheap solution, use more viscous oil.
This will definitely wear the pump out faster but can improve oil retention at
a typical cost of higher engine friction (and therefore heat.)
The problem can also be too high a pressure - this happens when the pressure
relief valve sticks shut and the pressure goes too high. You can tell with a
gauge, obviously.