Oil pressure change

[Goeer]

Since I bought my car the stock oil pressure gauge on my ba gt has always been very high and very constant. In fact it almost seemed stuck. After doing 1000 klms with the needle acting like this, I had an oil change, engine flush and new radiator fitted, even though the car has only done 100k. (The milk shake stories scarred the hell out of me ) Anyway,  since I had the work done, the gauge now fluctuates fairly wildly. Less than half while idling, then it raises while my speed does, and drops as my speed drops. This worries me a little bit, because before I had the service, the gauge indicated that I had high oil pressure all the time. And when I got the RAA (RAQ in other states I think ) for a flat battery, I pointed to the high reading on the gauge and he said that high oil pressure is a good thing.  Does anybody have a clue to why this could be happening. Is it normal to have a needle that moves a lot ?  Did the needle become unstuck ? Did the mechanic use the wrong oil ?  ( My whole family have used this guy for over thirty years ) My manual says my car needs very thin 0W oil. Do mechanics know what each car manual stipulates or do they buy in bulk and use the same oil for every car they service ? Maybe I am just worrying to much ?

[k31th]

You're worrying too much. The stock gauge is practically only there to tell you when you're heading to have low oil pressure, not to give an indication of what your specific nominal pressure should be.

 

Yes, the recommended oil is hard to come by, but you can safely put in 5W oils as a compensatory oil.

[El Andrew]

Totally normal for the reading to be lower at idle and higher with some revs. If you sit there an neutral and flick the throttle, you'll see the pressure rise and then drop again.

Not sure why it would have been constant before that.

[4321]

I think this is why cars generally don't have oil pressure gauges anymore. imagine the warranty claims & stress on both sides these 'problems' are giving. AU1's had a oil pressure sensor fitted but after that they all got a oil switch, no oil pressure it read 0, any oil pressure 2/3 on the guage- I bet solved a lot of warranty claims. Remember fg fpv's had oil temp not oil pressure. Back in the old days it was 10 psi for every 1000 rpm (and yes you can have to much oil pressure)

[Goeer]

Thanks guys for putting my mind at ease. I didn't want to look like a fool asking my mechanic another stupid question.