Oil Pressure Dropped Dramatically After Service

[4drftn]

just serviced the r33's oil and filter like many times before (every 5000km), took it for a drive that night and found while i was cruising the highway in top gear (100km) the needle on the oil pressure gauge (factory) was sitting on 4, which is perfect oil pressure.

after driving for 1 -2 hours on the way back home along the highway i looked at the oil pressure gauge again only to discover it has dropped near halfway between 4 and 0.

next day (today) went for another cruise on the highway and discovered it is slightly lower than halfway between 4 and 0. thought maybe oil pressure hasnt built up so kept driving. come back along the long highway and discovered it has sligtly dropped lower...

*now i usually use repco oil filter and valvoline dura blend (synthetic blend) 15w-50 oil, but this time i used a valvoline oil filter and same type of oil but 10w-30...

could this be my oil pressure gauge playing up?

what could be causing it to lose pressure slowly, or gradually?

could it be the type of oil?

could it be the oil filter?

could it be the oil pump?

could it be the pump is blocked/stuffed?

i imagine if the problem is not resolved it can/will cause me some serious problems.

4drftn

[Godzilla32]

Most likely the different viscosity of oil coupled with a dodgy oil pressure sender. I dont think id be too worried, if anything was seriously wrong you'd already know about it.

BTW: Keep in mind as the oil heats up more and more it gets thinner and thinner resulting in less oil pressure.

Edited July 12, 2008 by Godzilla32

[Nismo_God]

yep different oil is causing the different reading.

thinner oil for one, and heats up quicker (also making it thinner)

wouldnt be worried

[blind_elk]

What oil (brand, grade) did you put in? Have you checked oil level? No oil leaks around the filter?

[4drftn]

i used 10w30 valvoline oil, when i usually use 15w-50, yes i have checked the oil level several times and found the level to be on the correct level on the dip stick, i have checked the oil filter and found to have no oil leaks around the seal.

im a bit worried about oil not getting to some parts of the motor and possibly causing it to starve.

[Godzilla32]

If it wasnt then you would already have a problem. My gauge was always reading pretty low too. I pulled my entire engine down in the rebuild and it was all fine

[Kujotk]

could be thinning of oil or just a faulty reading,,,,, either one doesnt cause probs...... if your loosing lots of power when car shouldnt be too hot then start worrying lol

[Amec]

an aftermarket oil pressure gauge would tell you for certain what pressure you are running. the stock gauge can and does play up often.