Z ROADSTER

Well , I tried that Pennzoil Platinum 10w30 Synthetic motor oil last change ( 3000 miles ago ) . Then I noticed my oil pressure fluctuating back & forth at idle (hot) & in drive . Also that's when I noticed the pressure was way down , almost at 27-28 lbs. at idle . So I figured even at 10W30 this oil was thinning out . Went back to GC 0W30 and now my pressure is back up to between 38-40 lbs. at idle . Knowing how sensitive these motors are about oil pressure I thought I should warn ya'll about this . So be cautious cause that stuff is as thin as Mobil 1 .

crainholio

iTrader: (2)

Good data point. I've been using Pennzoil Plat 5W-30 in my truck and observed similar pressure readings during this hot Summer weather.

slt200mph

iTrader: (42)

Been using Mobil 1 for the last 164,500+ miles on this engine...used Mobil 1 0-40 until it had 125,000 than switched to Mobil 1 high miles 10-40 ... the car uses a half quart every 5,000 miles on a 5,000 mile oil change interval...this car sees the red line every day and is a daily driver ... been modded since 10,300 miles and makes 452 HP at the rear wheels ... to me Mobil 1 has done all I could ask from a motor oil..to the original poster do you have a real oil pressure guage or are you looking at the pos factory guage...you may want to invest in a real guage if you are concerned about what your oil pressure really is.