Switching Different Brands of Oil

[Baldie88]

Yeah, it's another oil question but I did a search and couldn't find what I was looking for. We've all got our favorite brands of oil and opinions on which is better than others. I've used Valvoline 5W-30 for probably 20 years. Anyway I had the Vette serviced recently and since I was without a garage (I usually do my own), I took it to the local Chevy dealer. They used Castrol 5W-30 and an AC Delco filter (I also use AC Delco filters). Anyway I now seem to be running about 10 pounds more oil pressure than what I use to when I had Valvoline in it. It seems to be the same 10 pounds across the board regardless of the RPMs. This is a good thing in my opinion but I wouldn't have thought different brands of oil would have a different affect on the oil PSI.So my question is, has anyone else switched brands of oil and noticed a difference in their oil pressure?Thanks,"Baldie88"

 

[tigmaned]

thats because valvoline is not as good, i used it once after useing castrol and noticed lower oil psi so i stopped using it!! i use castrol 10-30.in most of my cars and i mix with there syntex brand too. and yes 10 more psi is good too me!!! my vette is around 65 psi at start up, and drops to 55psi at idle warm but thats with mobil one.

 

[MBDiagMan]

It does not mean that one oil is better than the other. It means that one oil is HEAVIER than the other.

Have a great day,

 

[Baldie88]

If both are the same weight (5W-30) shouldn't both have the same viscosity? I would think they should be fairly close but not enought to raise my oil pressure by 10 PSI. I guess I'll run what I have left of the Valvoline through my other cars and switch to Castrol. Back many years ago I use to always use Quaker State till I switched to Valvoline for whatever reason. Always learning which is why I visit here each day. Ron

 

[Edmond]

That is weird. My thinking is that there is some other reason why the pressure has changed.

 

[Dean Barker]

Oil labeled 30 weight falls within a range. Valvoline is at the low end and the Castrol fall near the high end. If you have access to SAE books, the actual range is listed. There may be other places, also.

 

[vett boy]

Dean is correct and keep in mind that it can vary case by case due to the refining process.I can't tell you which ones for sure but a lot of companies joint buy or lable. Example Sears,Motor Craft,GM do not produce or refine oil they buy it and lable. When you buy a gallon of mobil oil it might be Exxon.The world is not as it seems. Steve

 

[koolaid117]

The world is not as it seems. Steve

Absolutely!!

 

[Edmond]

Dean is correct and keep in mind that it can vary case by case due to the refining process.I can't tell you which ones for sure but a lot of companies joint buy or lable. Example Sears,Motor Craft,GM do not produce or refine oil they buy it and lable. When you buy a gallon of mobil oil it might be Exxon.The world is not as it seems. Steve

Hey, that's what they do with the oil filters as well!

 

[code5coupe]

When you buy a gallon of mobil oil it might be Exxon.The world is not as it seems. Steve

That's because Mobil and Exxon are one and the same now. Look at your Mobil gas card...

I've noticed that old oil...that which is ready to be changed out at 5000 miles...seems to "thin out" somewhat. It will give lower than normal pressures. So, even when you replace it with the same brand oil, the oil pressure seems to take an unexplaned jump. Maybe this has to do with different oil lots being in different areas of the viscosity range.
BTW, I run Valvoline full synthetic in all my vehicles. It's good stuff. Oil pressure is not the sole criteria of engine protection....you only need "enough" pressure. More than enough is wasted. Valvoline syntetic is better oil than we'll ever need. So is Castrol synthetic, so is Mobil. As long as they meet the GM4718M spec, you are good to go.

Larry