1.6 Aircon Sump/oil Pickup/dipstick Differences?

[inferno 1]

my aircon gti has brilliant oil pressure, as a recon engine should. yet for some reason today the oil pressure dropped in the space of a 30mile journey, from 2bars hot idle/3bars hot running at 2-3k,and about 4 bars giving it loud pedal.

 

it dropped to nothing on idle with oil light flickering, to 1-2 when driving but never hit 3 bars for the last 5 miles or so.

 

when i got back i checked to find id used from max to halfway to max, in around 600 miles. that consumption seems good to moe considering ive driven it quite hard and in the hot weather recently.

 

i topped it back up the max, and the oil pressure is back to how it was! im really suprised there was no inbetween warnings, and theres no sign of smoke today or oil leaks or anything.

 

when i fitted the engine i had to swap over aircon specific parts like the sump and oil filter relocater ect, should i have used a different oil pickup? or different dipstick? it seems to me like it ran low on oil...