Motor oil rating's very important



What the differance from autozone oil Mobil 5w30 rated sh on back bottle seal and WalMart 5w30 brand oil rated sh on back of bottle seal. My under standing is there are only two oil manufacturing Co. in the county. Where’s all the oil coming from. 89 mercury


The difference is the name on the bottle.

You can use any brand of oil in your engine, as long as it is the correct viscosity (10W-30, 5-W-30, etc.) and has the correct API letters (SJ, SH, etc.) on the back.


There are different additives in the motor oil recipe. The most important thing about motor oil is not what brand as long as it meets spec, but that you actually change it at appropriate levels and check the level occasionally.


Think of the API letters like the USDA stamp when you buy meat, it shows that the oil meets the minimum requirements to obtain that rating. The engine manufacturer requires you to use that oil as a minimum to support their warrantee. If you wish to pay for additional additives, quality control, etc. you can buy a product that exceeds these minimum requirements. The benefits of buying higher quality oil are usually very long term, well beyond to original warrantee. You need to decide if you want/need to pay for that.

I agree that it is probably more important to change the oil/filter at the appropriate intervals than worry about the specific brand.

#5 has an excellent primer on oils. I recommend a visit.


“…My under standing is there are only two oil manufacturing Co. in the county. Where’s all the oil coming from…”

Surely you mean country!

And surely you aren’t serious that you believe there are only 2?


Well there are a lot more than two oil companies making motor oil.

As noted it is not all that important what company made it or what name is on the label, but rather what weight (5w30 etc.) and what API specifications and that you use what the car manufacturer recommends for your engine. For gasoline (Spark ignited engines you are interested in the letter after the “S” for diesels (Compression ignited) it is the letter after the “C”. You can use later/better letters (that is if SH is recommended SI, or SJ etc. would all be OK.

Some manufacturers have their own specifications like VW. VW is using numbers like 505.03 Since they are measuring with a totally different yardstick you can’t compare them and say that a SJ can be equal to 505.02.

In short, find out what the specifications are for your car’s engines and using any oil that meets those specifications or higher.


If you have to add oil between changes and you have the 2.3 engine, you should have good luck with any brand of straight 30 motor oil in the summer. The word lately is not to use Pennzoil or Quaker state. The 2.3 is iron block and iron head with cam in block. It is somewhat indestructible. If you have the V6, the car is an 89 and you can feel free to buy the cheaper oil. 89s are easy to replace.


The word lately has been around since the 1970s. It is an urban legend regarding parrafin wax and sludge that might have had some truth, but probably did not and currently does not. I am sure people will respond about how this oil ruined their car, but they never have actual proof that it was the oil’s fault. I was going to ignore this, but I get so frustrated with the misinformation on the net.