Oil. synthetic vs. mineral oil

[z122643]

So I have an iX with the M2025B engine. I've been using 15w40 Castrol (mineral) and I wanted to switch to synthetic. I'm just completing a complete engine rebuild so I thought I would get some opinions.

Mobile 1 says to use 0w40 synthetic. What weight synthetic is best for an California climate?

[Cletonius]

Where in CA? If I was in socal I would run 20w40 all year.

[z122643]

I live in SoCal and NorCal. I will be in temps between 30F-100F

[jlevie]

For temps that don't go below freezing, you want a 20w50 oil. There is no reason to use synthetic in an E30 since the oil/filter changes need to be at the factory interval. The longer life of synthetic oil can't be taken advantage of on these engines.

[Apps]

For temps that don't go below freezing, you want a 20w50 oil. There is no reason to use synthetic in an E30 since the oil/filter changes need to be at the factory interval. The longer life of synthetic oil can't be taken advantage of on these engines.

Lubricity is a clear advantage of synthetic oils no matter what the service interval. It's been written up many times before and does depend on the base stocks used but synthetic will always provide better lubrication for a given ppm. There is a reason race cars are using different synthetics then you're off the shelf Castrol or Mobil 1...

[KenC]

If it's a DD and you're not tracking it, just run 20w50 dino for diesel engines. They have a really high ZDDP content.

[MR 325]

Another vote for 20w50. There is absolutely no need for synthetic in these engines.

[HR2L]

Another vote for 20w50 non-syn. I use the Valvoline VR-1 non-syn oil as it has higher levels of ZDDP and it seems to work good. Castrol GTX High Mileage seems to be another highly used oil for our cars as well. :)

[Cabriolet]

im with MR325. really its not about synthetic or non-syn. its about changing it often every 2700-3200 miles. in Ca, 20w50 is perfect year round.

personally i use full synthetic 10w40. i have a fresh rebuilt engine and push it autoX and drive like an idiot 5 days a week. but i still change mine every 2500 miles.

[HR2L]

im with MR325. really its not about synthetic or non-syn. its about changing it often every 2700-3200 miles. in Ca, 20w50 is perfect year round.

personally i use full synthetic 10w40. i have a fresh rebuilt engine and push it autoX and drive like an idiot 5 days a week. but i still change mine every 2500 miles.

Agreed. I usually change my oil every 3k-3500 miles (DD my e30). Sometimes I run a little blend (weight) I will do 3.5qts of 20w50 and 1.25qt of 10w40 during the winter time. ;)

[MonkeyMadness]

Another vote for 20w50. There is absolutely no need for synthetic in these engines.

yep yep...

[MR 325]

Another vote for 20w50 non-syn. I use the Valvoline VR-1 non-syn oil as it has higher levels of ZDDP and it seems to work good. Castrol GTX High Mileage seems to be another highly used oil for our cars as well. :)

VR-1 is AWESOME. Definitely pricey but a really great product. I use it in my M20.

[aTron12]

I'm up to 240K and am running 20-50 synthetic.

[JrCamacho]

Another vote for 20w50 non-syn. I use the Valvoline VR-1 non-syn oil as it has higher levels of ZDDP and it seems to work good. Castrol GTX High Mileage seems to be another highly used oil for our cars as well. :)

ZDDP!

20w50 here, and my m20 loves it.

[digger]

I am not sure how you guys can say one oil is better than the other without having tested them scientifically. The fact is most manufacturers are sketchy as to what is in the oil.......