K&N Filter Setup/ Low oil Pressure

[Luke2.9]

I´m running a K&N Filter setup on my ´89 Ranger 2.9l. I´ve plugged the vacuum hoses on the old airbox. Since then oil pressure is lower than usual
(no exact measurements yet).

any ideas?

 

[dave2575]

Need more info. Witch k&n setup, the actual cold air k&n system/or stock filter replacement, or are you using the good ol clamped to TB hot under hood air k&n setup? did you plug ALL the vacuum line fittings(air box, upper intake manifold)? are you using a mechanical oil pressure gauge for your oil pressure reading or are you going off the warning light? did the low oil pressure start at the same time you changed your air intake system(hint)? did you check or reset your codes after the change? and did you remember to do the hokie pokie and turn yourself about? you know that's what its all about, right? OK OK... I know a couple of these questions are irrelevant but ill give you a "HINT" witch one is...

 

[Luke2.9]

I´ll try to ask some of the questions...
I´m using a conical k&n filter clamped to the throttlebody.
I left the original airbox with the vacuum lines attached to the upper intake.
( I need to bolt back the old airbox quite often due to german emission tests) but plugged them on the airboxes side.
I use the reading of the oil pressure gauge in the dash.

The problem started after changing the air intake, when I bolt back the original airbox, oil pressure is okay.

I did not check or reset codes, since I don´t have the device for it and don´t know how it´s used

Engine vacuum is okay.

Could be relevant: There is one leaking head gasket, which is obviously leaking no matter what air intake is used.

Thanks for help