I just got back from a cruise in my 97 Z. On a long straight road I wanted to go through a couple gears since it has been about 1500 miles break in on my new 3.73 gears and clutch. Anyway, as I was letting the car whined up through a couple gears I had time to look down at my oil pressure gauge and noticed that the needle surges, or fluctuates sometimes. If I remember correctly at WOT (not sure of rpm) it would fluctuate to as low as 40 then back up a little..I have never noticed this before because im usually looking at the road when doing this, but is this normal or should the needle be perfectly still. Im not talking about while shifting gears either im referring to while in a gear at WOT.
FYI, I use mobile one 5W30 oil and mobile one filter. So my oil quality, and quantity is not a problem here.
Maybe this is perfectly normal can someone fill me in?
Thanks a lot

 

My oil pressure goes up at WOT, and goes goes down after i let off the gas.

 

Have you ever had the intake leak on your car and had it repaired? If any of the sealant (sp? it has been a wierd day ) breaks off it might get stuck on the oil pump pick-up and will cause a problem very similar to what you have. The only way i am aware of how to fix this is to drop the pan and clean up the pick-up screen. FWIW my oil pressure at WOT is about 60 or 65.

 

It should fluctuate a little with RPM change. The general rule of thumb is 10 PSI for every 1000 RPMS. For example: At 2000 rpms you should have at least 20 PSI give or take a little, at 3700 rpms you should have around 37 PSI, etc. I didn't see where you were from but if it gets pretty toasty where you are in the summer I would definately use 10w30 or something similiar for the summer and due to the extra thickness of the oil your PSI will be a little higher than normal too if its too low for your liking.

 

I am located in Daytona Beach FL right now where the current heat index is 97 degrees. Infact when I pulled into my parking spot my brakes were smoking:-) I am using the 5W30 so you think this may be too thin for these very high temps?

 

Yes, definately use something thicker like 10w30 or 10w40.

 

if you want thicker oil when its hot you have to use a 5w 40 or 10w 40. the first number is how well it performs (pours) at cold temperatures. i used to think that 10w 30 was thicker than 5 but its not. the best oil to use would be 0w 40. mobile 1 makes it but its kinda hard to find. and if anyone disagrees with me do a search on here. some guy was like an oil expert or something and explained this to alot of people.