Oil pressure drops

[SimonB]

Hi I have recently had an oil pressure gauge fitted to my mk1 stag and when the engine is cold it reads about 50psi but as the oil and engine warm up the pressure drop to the point that when stopped in traffic it is almost non existent and the green oil pressure light flickers. Mine is an auto and if I slip it into neutral the oil light goes out but pressure is still low. Also I notice that when the engine is off the oil must drain back down the tube and there is air gaps and I wondered if this is causing a false reading? Has anybody any ideas!! Thanks I love this forum I seem to spend most of my time reading the threads and have just spent about three days on and off reading about the Barvarian Stag, amazing what he has done! Thanks in anticipation. Simon

[milothedog]

Hi I have recently had an oil pressure gauge fitted to my mk1 stag and when the engine is cold it reads about 50psi but as the oil and engine warm up the pressure drop to the point that when stopped in traffic it is almost non existent and the green oil pressure light flickers. Mine is an auto and if I slip it into neutral the oil light goes out but pressure is still low. Also I notice that when the engine is off the oil must drain back down the tube and there is air gaps and I wondered if this is causing a false reading? Has anybody any ideas!! Thanks I love this forum I seem to spend most of my time reading the threads and have just spent about three days on and off reading about the Barvarian Stag, amazing what he has done! Thanks in anticipation. Simon

Hi Simon, sounds like you engine may be a bit tired, has it been rebuilt in the past? a new oil pump may improve things a little but in the short term and a quick thing to do, try changing the oil and refill it with Valvoline VR1 you may be pleasantly surprised.

Another thing is to increase the idle speed if it's very low, ideally you want about 750-700RPM which should dip to around 600 RPM in gear. Air in the pipe is normal and the fact the light and the gauge are telling you the same thing suggest what I said above.

Ian

[SimonB]

Thanks Ian , the car was supposed to have had a rebuild less than 6000 miles ago but I now doubt what I was told was genuine, I will try changing the oil pump and the Valvoline. When you say the engine may be tired do you mean the bottom end? Thanks Simon

[jleyton]

Hi Simon,

I was in a similar position to you a couple of years ago. I dropped the sump and, fortunately, my crank was in reasonable condition and so new big ends and mains and an overhaul of my pump sorted mine out.

All in all it wasn't too hard a job and whilst I hope a pump and VR1 sorts you out, if it doesn't, then it may still be a relatively easy job.

Cheers

Julian

[milothedog]

Thanks Ian , the car was supposed to have had a rebuild less than 6000 miles ago but I now doubt what I was told was genuine, I will try changing the oil pump and the Valvoline. When you say the engine may be tired do you mean the bottom end? Thanks Simon

Yes, crankshaft bearings/oil pump as Julian has said, but if as you say it may have been done 6000 miles ago it may just be the pump. A new pump and oil and filter as you said is the best way to move forward, and not difficult to do or that expensive. There are a couple of other things that can allow pressure to drop at idle but lets see how you get on with the pump first before delving deeper.

Best of luck with it.

Ian