HELP!!! funny oil pressure readings!!!!

[Kiwi_Fozze]

hey guys, i installed an oil pressure guage some 4000 km ago, at first install i was hitting just over 100psi cold idle, sitting at about 15psi warm idle, driving around i averaged about 70ish psi under normal conditions...

i\'ve been keeping an eye on it, and it\'s slowly been dropping. high rpm (warm) i\'m lucky if it hits 60psi, cold idle hits 60psi, warm idle is still about 15 ish, and i\'m a little worried... it hasn\'t been burning any oil, not making any funny noises etc.... any idea whats going on??

pressure sender is in a sandwich plate under the oil filter, but i don\'t see how that could cause a progressive steady drop??

[funkytown]

if you remove the oil filler cap with car running does it blow a bit of air at you?

[Kiwi_Fozze]

i don\'t like the sound of that... i\'ll go check

[Stoffa]

try instaling your sensor in an oil gallery, your measuring oil pressure before its been through the oil pump.

[Kiwi_Fozze]

oh f**k

i think it\'s the head gasket.... fuffs of air blown out at me...

[Kiwi_Fozze]

also air bubbles in the oil... but nothing in the water...

[Stoffa]

how does a head gasket effect oil pressure?

[rex-leggy]

 Stoffa said:

how does a head gasket effect oil pressure?

it doesn\'t normaly . for combustion to get to the oil galery it has to first get past the water gallerys . so very unlikely its the head gasket.

some blow by is normal. is it chuffing out a crap load with smoke? was it bubbling after a massive thash?

also whats high rpm to get 60psi?

[Kiwi_Fozze]

high rpm being over 6k. chuffing out enough to make the beard hairs ruffle, no smoke.

will check cold oil levels in the morning to see if it\'s eaten anything in the last week or so. faaaark....

[Stoffa]

I have read of the oil bypass valves getting jammed in oil pumps causing pressure dramas but if that was the case you\'d probably have no oil pressure or sky high pressure.

Have you got enough oil in the sump? (have to rule out the easy things first)

My engine builder says you needs 10psi/1000rpm so dont go revving it too high with oil pressure problems. so less than 60psi dont take it over 6000rpm.

[Kiwi_Fozze]

if theres no oil, then i REALLY need to sort out my rocker covers lol, last oil change was 4k ago. will check once it\'s cooled down a bit.

[Stoffa]

also if its in the sandwich plate, it may have crapped itself from the exhaust heat, especially if its a cheap nasty sender/gauge

[Kiwi_Fozze]

gauge is cheep, sender is a vdo one... they are ment to be good?

[Kiwi_Fozze]

mmm plenty of oil in it, no bubbles in the water, or oil in water...

[reaperblitz]

What oil is in it?

[Kiwi_Fozze]

10w40 valvoline stuff. going to magnatec if i have enough free cash next oil change

[reaperblitz]

Oh ok. FYI it\'s summer now. Rise in temps may be affecting your oil viscosity/ pressure? Does it change back to higher pressure when you drive around at night in the cool?

[Kiwi_Fozze]

nope, still s**ty low pressure. might be the sender... i dano, it\'s doing my head in now

[chappell943]

 kwi_fozze said:

nope, still s**ty low pressure. might be the sender... i dano, it\'s doing my head in now

Id try another sender first just in case it is something as simple as that, also due to the fact they are exposed to a lot of heat which probably doesn\'t do them any favors.

[Kiwi_Fozze]

Well, i\'ve disconnected my a/c, so who would be the best contact for a alternator flip, and one of those funky double connectors for the standard oil pressure sender and the vdo one? At the top of the block?

[Stoffa]

Just remove the factory one or use the gallery next to the crankcase breather

[Kiwi_Fozze]

turns out it was a faulty sensor. swapped in a new sensor, worked perfectly fine, readings as they should be. MASSIVE sigh of relief.

oh, FYI, to get a bung, that goes in to the oil gallery above number 3 cylinder, with a 1/8" npt internal thread, these ARE a factory subaru part, costs just on $40 from winger subaru, imported. bit pricey, but it\'s a factory part. and generic across EVERY subaru block. good aye?

[Guest]

 kwi_fozze said:

turns out it was a faulty sensor. swapped in a new sensor, worked perfectly fine, readings as they should be. MASSIVE sigh of relief.

oh, FYI, to get a bung, that goes in to the oil gallery above number 3 cylinder, with a 1/8" npt internal thread, these ARE a factory subaru part, costs just on $40 from winger subaru, imported. bit pricey, but it\'s a factory part. and generic across EVERY subaru block. good aye?

Faarrrk you coulda gone to an engineer shop and saved a dozen pies...and v\'s too.

Flipping the alt is a piece of piss just cut some off material off the alt mount and mount it the other side. I made a temp bar that tensioned on the p/s pump bracket and pivoted off the alt till I bought the right thing off a member which didnt fit right...got it to work in the end though. All on my build thread.

[Kiwi_Fozze]

lol, only thing that actually cost was a new sensor, rest of it was all pulling s**t apart, which is a piece of cake

bought the oil gallery bung because it\'ll be going into the next car too

[pipdogg13]

 kwi_fozze said:

lol, only thing that actually cost was a new sensor, rest of it was all pulling s**t apart, which is a piece of cake

bought the oil gallery bung because it\'ll be going into the next car too

how much was your sensor? i think i might need one too, my sti is doing the same thing...doh!