Older technology engines=different oil?

[qezel]

I feel that with all this new oil technology even an older sohc engine should reap the benefits. I see no need to run a 20w50 dino oil in a car just because it's what the 1985 owners manual says to. I do run oil like this, but only in things where I don't think the added cost is offset by the protection(sometimes the engines too worn, or its an engine known to not wear and doesn't see that hard of driving, etc) but some guys believe you HAVE to run those older style oils. If I plan on running a good engine hard, even if its old I don't see a problem with GC or another 0w40 syn. They're about just as thick as the 50 which the manuals call for but stand up to eat better and don't kill the thing when its cold. Who's more right? Should I use vastly different oils in older cars because of the different valve setups(most modern engines don't use rocker arms anymore) I usually just switch up viscosity's car to car. I have heard arguments that the older style bmw engines(not just high mileage,but more so different technology from 70's/80's engines) need more ZDDP because of how the top end is oiled(SOHC with a spray bar above cam). Is this true? Do oils like GC not have enough ZDDP and other addetives for these engines?

Thank you

 

[bmwtechguy]

If you do run the dino 20W-50, just save it for the summer heat. I would use a 5W-40 diesel-rated oil in that thing for winter, something like Rotella 5W-40 syn. Or maybe 0W-40 for real cold temps. Or 10W-40 HM for summer. Stick with something that has the higher additive levels for that older engine. Only way to know if the GC will do well is to use it, then have the use oil tested. GC is pretty stout and will work well in some older engines. You have to look at consumption too. GC prevents wear pretty well due to it basestock/additives combination, even though the add levels are not as high as some of the others mentioned here. I prefer the 40 weight diesel rated oils in the older engines, even the conventional 15W-40 oils. Some cars need a 15W-50 or 20W-50 in the summer, depending on the engine's condition and just how hot the ambient summer temps are in your area.

 

[qezel]

Here in CT we aren't the Yukon, but it gets plenty cold. Most days you can clearly see the advantages of a 0w at startup, either you have no oil pressure or its just pegged until you really get some heat it on a 10w. 0w can be thinned out to almost normal in under 10 minutes of running. Summer I like a 40 or 50 depending on the car because not only does it get hot, but I tend to really drive cars in the summer vs the winter.

 

[Camu Mahubah]

I am having a bit of trouble discerning what brand of manufacturer these automobiles are.

 

[Camu Mahubah]

Are the Auto Union?

 

[Camu Mahubah]

Meant to say are they Audi's? And are you located in Conneticut?

 

[bmwtechguy]

I assumed BMW because he mentioned it. But I may have assumed wrong.

 

[qezel]

Yes, I would be asking about BMWs here. The audi's love GC if they're run hard, if not Kendall is fine.
Thanks

 

[Camu Mahubah]

Oh, okay I see. In your signature some Audi are listed. I think the older Bimmers need some AMO.

Pics Please...

 

[glennc]

Took me a few minutes to figure out your sig.

Audi 4000S Quattro, Daily Driver
Audi Coupe GT x2
Audi 90 Quattro
Audi 90 Quattro 20v x2

7A? No idea.

What BMW are you referring to?

The conventional wisdom is that the BMWs in general like thicker oils. I have accepted that in the past but I have seen some very good UOAs with thin oils even on the older ('80's) ones.

Also you can't read about oil anywhere without running into the idea that "flat tappet" engines need more ZDDP. However I really have not been able to ascertain whether this is based on good evidence or whether it's a myth that has just been passed around in circles since the SL days.

I think there is good reason to believe that in a modern SM oil the performance will be excellent despite lower ZDDP and other additive levels, because 1) the base oils are better, 2) new additive chemistries are being employed, and 3) there is continuous research into the particular relative concentrations of various additives that helps optimize the precise blends used and further refines performance.