Went out for a bit of fun tonight to practice my launches off the line and after a couple of runs my oil pressure gauge sat pretty low (about 1/3 pressure from it's usual 4/5 mark). It stayed at this point if I just let the car idle on the spot until I give the throttle a blip and the pressure goes back to normal. The oil pressure light did not come on either so hopefully its not bad bad. It is a new oil pump (only 1500km old at most) as it collapsed 4 months ago and forced me to have the timing and distributer shaft replaced as they got chewed out.

Question it what is the cause for the low pressure.
Is it the oil weight used by the mechanics being to thin?
Or is the timing chain out of position (computer adjusting)?
Maybe a faulty oil pump/sensor?

Any suggesting will help save time and money...

Thats normal, the actual owners book, for mine, states that it will drop, as long as it dont go in the red, and the light comes on, your right. I use 25w70 in my motor, no probs, and it sits halfway all the time, at idle, and around three quarters at speed.

Thanks Bowsaw. I figure that most of the problem is with the oil as it is only a bulk commercial variety stocked by the workshop. I have plans on doing another oil change for some quality oil and see if the problem persist.

Mine sits on the second bar constantly while driving, and at idle drops to almost 1 bar. Not good, but oh well.

Yikes. 25w70? It's an engine, not a diff. That's far too thick and if you're engine rattles with anything thinner, it was time for an engine rebuild about 100,000km ago.

As we all know, oil pressure is a slave to two factors.

1. Oil viscosity
2. Engine speed.

Of course the oil pressure is going to be low @ idle. This is a GOOD thing, not a bad thing unless the oil pressure light comes on. As engine RPM increases, the oil pressure only increases, so you don't want high oil pressure @ idle as wehn you revv the tits off the engine, the oil pressure will go too high and cause problems!!

Your oil pressure, while perfectly normal and safe, was probably caused by an increased oil temp from all the fun you were having. A 'quality' oil of the same weight would have given you the same results.

I think I use the 5-60 in my car, or is that 15-60. Anyway I'm starting to think it's not necessary for a car that's only 165000 young and doesn't blow a hint of smoke.

Should I consider using a thinner Penrite oil, I've heard you can get better fuel economy as the engine doesn't have to work as hard against the high viscosity oil?

1990 Spac 225,000k's idles on 1 bar and anything above1500rpm on 3/4 scale. This is on an EL dash. Oil pressure when cruising on a very hot day will drop to just under 3/4. Still 1 notch at idle. I would suspect there is a problem if at cruise when hot the pressure is substantially down (below 1/2 scale) I use 2-50w oil PENZOIL never had any issues in any of my cars including the Commodore ( sorry for the bad language)

20w50, of whatever I can get my hands on
Sit's on 1 notch at idle, and rises to the 2nd notch at revs.
When it's still a bit cold, it can get as high as middle of the gauge, but it all seems fairly normal to me.

Yeah mine sits around 1 bar when warm and idleing. When cold over 2 or when you give it a bit. I would worry until you get a warning or the engine makes bad noises.

Ben