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Discussion Starter #1
Hey Guys,

I just picked up an E28 M5, US spec. As far as I've known, it's always been filled with 15W50 dino oil.

I picked up some Redline Synthetic 15W50 yesterday, and I'm going to make the switch this weekend. I do realize that engine seals can absorb synthetic quite a bit more than conventional dino oil, re-lubricate them, and perhaps cause some leaks.

If any of you have made the switch, did you spring any leaks? Where did you see them?

Thanks!
Jeff
 

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Discussion Starter #2
Update:

I made the switch to Reline 15W50 last night. No immediate leaks, but I'm going to keep an eye on it for about two weeks. I'll post info after that period of time and perhaps inspire some of you to switch.

Impressions: Engine felt immediately smoother, and quieter (if thats even possible with an S38 :hihi: )

If I don't see any leaks I'm going to switch to a lower viscosity grade synthetic.
 

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I would not switch to a lower viscosity oil until the weather demands it for the inital cranking. In the summer I run Mobil 1 15W50 exclusively. I have done this with 5 different S38 engines and the oil works at an interval of 7,000 miles. The engine stays extremely clean.

In the winter I go to Castrol 10W60. I use this because of the lower temps in the winter. 15W50 will crank in the winter, but the cranks are very very hard and you can feel it. The 10W60 works extremely well in the winter and I have cranked the engine at roughly 0F and it worked perfectly.

BTW, these are all synthetic oils. At lower temps dino oils become ultra viscous, and actually can form solids. Dino oils at higher temps can degrade and lose viscosity, which is necessary to a certain point. Put some dino oil in the freezer along side of some synthetic and its obvious which will do the job correctly.
 
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