Using 5W-40 on Z's with no oil cooler

Zyonara91

If you want to learn about oil in depth, go to bob is the oil guy. You can spend hours there looking at UOAs and VOAs of all the brand of oils and their viscosity. Talking about oil is mental masturbation and people will say this is the best and that is the best.

Here is the conclusion I have come to after spending hours on BITOG:

1) Not all oils are the same. A 5w30 synthetic oil vs a 5w30 syn oil with a Merc 229.5 and Porsche A40 approval are different. The latter will contain a higher HTHS rating, TBN and possibly more Zinc, Boron etc.

2) Some oils have a better BASE oil compared to other oils with the same viscosity, PAO, esters, hydrocracked etc. You have to read the data sheets to get a better idea and not all of the information is disclosed.

3) There are different groups of oils, I, II, III, IV and V. Some are blended together to get a good base stock. It is not unusual to blend group II and III together or group III with group IV, etc etc. It's chemistry simple as that. Better base oils usually contain PAO and Esters which give strong shear stability among other things

4) The BEST OIL is the oil you change on a REGULAR INTERVAL. Look for the approvals in your manual and change your oil AT LEAST once a year or every 8,000km or whatever comes first. I know some bottles say *up to* but that's if you have the ideal driving conditions, which many folk do not.

Anything you buy off the shelf that's "synthetic" (M1, Castrol, PP/Shell/QS) is good stuff and will give your car a happy life for everyday driving. There is a reasons why I placed synthetic in quotations, look at Castrol VS M1.

IF money is NO object to you and you could care less about what anyone says on a forum and you keep your oil changes to 8,000 km or less since you're against extended drain intervals. Go with Redline. I use their gears oils and they are fantastic, their oil is pricey but, it has Group IV and V (esters) and have great HTHS ratings and TBN. I've seen plenty of VOAs and UOAs and Redline always comes out stellar. However, I've seen M1 0W40 and Castrol 0w40, M1 ESP and PP Euro L UOAs and they come out stellar to, comparable to Redline for HALF the price if not more. . .

There is also the issue of LSPI, when to much calcium is introduced as a detergent, usually that's offset by Zinc and I think boron as well. Just put your nose to the books my friend and you will come to your own conclusion. Best of luck and enjoy the forums.

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