help with oil pressure build up


Mar 7, 2009
Hey guys,
ive been having issues with my bigport 4age 16v throttle body lately as its not shutting correctly, so i changed to a new one. i proceeded to drive it for a few days with the new Throttle body, but i realised the hole leading to the accessory thing was not plugged in, and it was idling high (constantly at around 1.5 to 2k rpm) and doing the stupid revving up and down that happens when the hole is not plugged in. when i drove it home with the new throttle body in i pulled up in my driveway and there was oil everywhere, and pissing out from under the hood. i looked under and noticed that the oil looked like it had shot from the dipstick hole, even thought the dipstick remained in its hole. im thinking that oil pressure has built up some how and shot out dipstick, then its fallen back into place. im wondering if there are any oil pressure regulators on the throttle body, or if there is anything i can do to prevent this happening when im on the freeway or something so i dont cook my engine.


Active Member
Nov 11, 2008
Snowy mountains
have you blocked off your crank case vent at all? from the cam cover. I dont think higher oil pressure would blow the dip stick out, but high crankcase air pressure would.

with the oil pressure there is a valve in the oil pump, you can put heavier springs in it to allow you to run higher oil pressure.


Active Member
Apr 30, 2006
Maitland, NSW
What gasket did you use for the new throttle body.

I'm betting you have blocked off the small hole needed as the pcv bypass in the throttle body and now the inlet manifold sucks straight from the cam covers causing a vacuum in the engine.

At idle take of the pcv hose and it may have a hissing sound if I'm right.

Search rwd inlet manifold pvc smallport for info.