Thanks for all yer help guys (atljar). one more question, though. i live in Fresno CA and in summer it can reach close to 105 with TERRIBLE air quality. what weight oil do you guys recommend i use to battle the heat and sh!tty air? also in winter it can dips into the 40s regularly, should i run a different oil during different seasons??

once again, thank you....

 

my 94 Z has 52K miles and has a little over 40 psi when cold and a little less then 40 when its warm. i run castrol 10w30. chevys just have lower oil pres. when my car is at idle it only has like 20 psi. but when i rev it up (warm), it goes to almost 40. FWIW, i wouldnt run a high weight oil like straight 30 or 40 weight. id prefer better flow and lower pressure then ****ty flow and higher pressure.

 

For a well broken in SBC (gen I or II) that is at operating temp, ~20psi at idle and 40psi max is not unusual. It does indicate some wear, but does not mean a catastrophic failure is imminent. Of course, if you suddenly saw oil pressures drop, that's a bad thing. If you want to see pressure a bit higher, which is not a bad idea if you run it hard, you could try Mobil 1 15W-50. It's what I run.

Rich Krause

 

It is apparent with the WIDE variety of temperature conditions, and extreme heat, synthetic is your best bet. Simply, this is where synthetic shines. Poor air quality yes, will indeed introduce more contaminents, but I mean specifically dusty or dirty conditions for my previous statement.

IF, the temps can go 40 - 105 within days, a seasonal oil is not your best bet. Saying that, Mobil 1 with Syntec has 75 new patents alone on this new blend. 5w30 is all you need. Any heavier and you're wasting HP to pump the oil.

The key is monitoring the life of the oil. It is possible to do 10 - 15,000 miles on synthetic that has a good air and oil filter and is mostly highway driven.

 

Zed,

im not saying that temps will change from 105 to 40 within days, i meant to say between seasons (winter/summer). so now, does that change your answer? im thinking maybe i should run a higher weight during the summer due to the heat killing oil viscosity...am i right?

another couple questions ( ), how does living in a dusty environment hurt yer oil? how does that dust get into yer oil? my best gues is than if yer filter doesnt pick it up then it ends up in the cylinders and combustion chambers, but from there i cant see how it gets into yer oil from there....

so know, i have had a recommendation for 5w-30 sythetic due to the fact that it takes less juice from the motor to pump a lower weight oil and although i will have less OP, i will have better protection. i also have had someone tell me to use 15w, for reasons that make sense too...so im still wondering.

also, i have the SLP cold air unit with my splash guard still on...and i clean the filters somewhat regularly...

 

No matter what air filter you have, dusty conditions will pollute your motor.

Oil ratings (the 30 or 40 or 50 weight) are measured at 100 degrees. Your car quickly doubles that at operating temperature. Therefore, it all comes down to the detergent package and protections.

SuperSyn has 70 new patents alone on their product, and it is stellar at hot temps. Patman, will pipe in here soon I'm sure. He does daily searches for the word "oil".

5w30 is fine all year long. Don't waste HP pumping what appears to be a thicker oil.

 

Ok for every 1000rpms you need 10lbs of pressure and also I hope your kidding when you say you use 5.5 quarts of oil??? only LS1's need that much oil. you should only be using 5. too much oil causes a drop in pressure due to aeration in the oil from the crankshaft. try a thicker viscosity oil to see if your pressure increases but in my opinion that pressure (40) sounds normal unless you stay up in the 5000rpm range for an extended period of time.

 

ok, took it out today when the car was REAL warm and opened it up and my OP didnt even get above 35 psi even at 5k. this sounds bad....

 

Any car that is fully warmed up will see lower oil pressures but here is what you SHOULD do... Drain the oil and cut the oil filter in half. look for metal shavings. You see any that are big or the filter oil is metalliccly shiny; you got problems...If not then change the oil with either a thicker weight...you should be using 10/40 or try 20/50 for s's and g's. Could be the oil pump pickup is dirty or the sensor is no good..Immediately following the oil change observe the pressure right when you fire it up. Synthetic oil runs thinner anyways then mineral oil. you should see around 50-65psi. If not after the oil change then try the easy way out and replace the oil pressure sensor. After that you still have low oil pressure it's time for a rebuild because you have high clearances in either the crank or the rod bearings.

 

Ive got 40psi max oil pressure... Never seems to go above 40 and I rev it to 6gs a lot. I also have a cam etc and its been like this since I've had the car 2,000 miles ago. Everything is still fine...

 

hmmmmm, maybe im worrying too much about this....