Recommended oil viscosity?
08-08-2016, 09:56 PM
#32
Consult the owners manual - find the viscosity which matches the average ambient temperature you plan on using your car.
The "high ZDDP" is grossly misunderstood. You want an oil that has the old standard prior to about 2002 or so which is 1100/1200ppm ZDDP. Almost every 15/20w-50 oil meets this. More difficult to find thinner oils with this level.
There are oils on the market with more ZDDP (like the air cooled motorcycle stuff) and more is not necessarily better. Stick with the "standard" for which these cars were designed, don't over do it.
Also, don't just dump in some ZDDP additive "just to be safe" - use a proper oil from the get go.
I've come across a number of 16V cars that have been running 5w-40 their whole life (like my 1980 with over 80k on the odo). I have yet to drive the car on a really hot day to report on what the oil pressure does. My 1981 threw a lifter clacking hissy fit when I tried 5w-40 many years ago.
The "high ZDDP" is grossly misunderstood. You want an oil that has the old standard prior to about 2002 or so which is 1100/1200ppm ZDDP. Almost every 15/20w-50 oil meets this. More difficult to find thinner oils with this level.
There are oils on the market with more ZDDP (like the air cooled motorcycle stuff) and more is not necessarily better. Stick with the "standard" for which these cars were designed, don't over do it.
Also, don't just dump in some ZDDP additive "just to be safe" - use a proper oil from the get go.
I've come across a number of 16V cars that have been running 5w-40 their whole life (like my 1980 with over 80k on the odo). I have yet to drive the car on a really hot day to report on what the oil pressure does. My 1981 threw a lifter clacking hissy fit when I tried 5w-40 many years ago.
Hugo
08-08-2016, 10:31 PM
#34
Rennlist Member
http://www.bobistheoilguy.com/forums...sale_of_obsole
Interesting..I find it challenging to believe that Valvoline cant get it to meet -a- modern standard.
Interesting..I find it challenging to believe that Valvoline cant get it to meet -a- modern standard.
08-08-2016, 10:31 PM
#35
08-08-2016, 10:38 PM
#36
http://www.bobistheoilguy.com/forums...sale_of_obsole
Interesting..I find it challenging to believe that Valvoline cant get it to meet -a- modern standard.
Interesting..I find it challenging to believe that Valvoline cant get it to meet -a- modern standard.
08-08-2016, 10:44 PM
#37
Just out of curiosity, is there anything wrong with using 0W 50? I'm thinking since it's the higher number (50) that indicates the viscosity at high temperatures, it should provide plenty of viscosity at high temps, but also circulate quickly on cold starts. Sticking with 15W 50 for now, since it's recommended in the owner's manual, but I doubt 0W 50 was even available back in the day.
08-08-2016, 11:02 PM
#38
Shameful Thread Killer
Rennlist Member
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I don't know about 'wrong' per se but the greater the spread on the viscosity modifiers, the lower the viscosity index(in general), and reduced hot oil viscosity standard(again, in general). Also requires a greater percent by weight of the additive package so the base oil is stretched further by volume due to being taken up by the additive package. I suppose there might be some esoteric additive molecules that could be made to have a high VI while also having a wide thermal range, but it sounds expensive. Unlikely to find it in a bottle of dino oil on your shelf at WalMart.
08-08-2016, 11:03 PM
#39
Rennlist Member
Just out of curiosity, is there anything wrong with using 0W 50? I'm thinking since it's the higher number (50) that indicates the viscosity at high temperatures, it should provide plenty of viscosity at high temps, but also circulate quickly on cold starts. Sticking with 15W 50 for now, since it's recommended in the owner's manual, but I doubt 0W 50 was even available back in the day.
The 928, the German Supercar, design by superior Germans.
Did not ask for 0 weight oil.
08-08-2016, 11:03 PM
#40
Electron Wrangler
Lifetime Rennlist
Member
Lifetime Rennlist
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Just out of curiosity, is there anything wrong with using 0W 50? I'm thinking since it's the higher number (50) that indicates the viscosity at high temperatures, it should provide plenty of viscosity at high temps, but also circulate quickly on cold starts. Sticking with 15W 50 for now, since it's recommended in the owner's manual, but I doubt 0W 50 was even available back in the day.
I wouldn't even begin to consider it. In Phoenix I never use less than 20W50
Alan
08-08-2016, 11:07 PM
#41
Just out of curiosity, is there anything wrong with using 0W 50? I'm thinking since it's the higher number (50) that indicates the viscosity at high temperatures, it should provide plenty of viscosity at high temps, but also circulate quickly on cold starts. Sticking with 15W 50 for now, since it's recommended in the owner's manual, but I doubt 0W 50 was even available back in the day.
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MT928 (04-21-2022)
08-08-2016, 11:15 PM
#42
Rennlist Member
08-08-2016, 11:33 PM
#43
The wider the range between the cold and hot viscosity ratings requires a lot more additives to make the oil do this. As the additive packs break down, so does the oil's ability to keep its viscosity. My theory is to run a 15w50 or 20w50 and don't run the car hard until you see the oil pressure gauge start dropping off of the 5 bar at idle.
08-09-2016, 01:53 AM
#45
Rennlist Member
Thread Starter
Okay guys, thanks for your help.
The jury's back, at least for me.
I read other similar threads until I almost got a headache...
Car service history in TX shows 20W50, so since GA has similar climate I will stick with that for now, unless I go with 15W40/50 for winter months here.
The jury's back, at least for me.
I read other similar threads until I almost got a headache...
Car service history in TX shows 20W50, so since GA has similar climate I will stick with that for now, unless I go with 15W40/50 for winter months here.