Hmmm. I just bought this car not too long ago and I'm running through it getting it back up to snuff.

So I changed my oil last night. When I took the old stuff out it looked pretty new, but VERY runny. Almost as if it was dilluted with a solvent (gas?) I don't think it was water because I don't have the white frothy crap that normally happens when oil and water meet. Then again, at the moment my crank case is vented directly to the atmosphere via the top oil fill tube nipple. Keep in mind this car sat for a year or two.

ANYWAYS, I just switched over to 10w-30 Royal Purple Syn and now I'm seeing under 60psi?? Before this my gauge seemed fine and read above 60psi. Is there any obvious reason for this?

 

thinner oil? when it gets warm it should be at or around 30 psi and at wot or full load at or close to 50 to 60.

thats what i think.

 

Actually, I have found the same thing, after a change (regardless of how dirty and runny the old oil is) I have lower pressure. (Now my car has 180,000 miles on it, so I use 15W40 oil.) However, I think that you will find that your oil pressure gauge is sketchy at best, and my engine has 35psi oil pressure when the guage is pointing to 0. Idling at more than 20 psi on the gauge is really pretty good.

As to obvious reasons, I can't think of any, every piston engine I have ever had had much higher oil pressure after a change.

(It is possible that the potentiometer in the oil pressure sender has shorted places on it where the oil pressure usually runs, causing a higher reading at those places and a lower (more accurate) reading at higher pressures. That is my only theory.)

In short, don't worry about 60 psi oil pressure, several of my friend's RX7s oil pressure gauges sit on the peg below 2500 rpm and their cars still work great.

(If you are concerned about you gauge's inaccuracy, get a mechanical guage and screw it into the place where the sender is now - right below the oil filter.)

 

I would not worry the gauges are shitty.

my gauge reads 100psi at wot and 60 at idle in my 86 coupe.. in my 89 vert it is abotu 30 all day

however I would recomend using a 15w40 or better yet a 20w50

I use elf synthtic in the coupe 10w50 love it it works great..

good luck

 

Do you know what weight of oil was in to before? 10W30 is a pretty light oil for our motors in the summer.

 

Not off hand, but I'd assume 10w 30. this looked about 0w-10. Not that they make that but still. It looked thin. I used to change oil for a living so I should know something....