Whats your weight? (synthetic oil)
 

Since I'm considering switching to synthetic oil, I think it's suiting to start a poll on oil weight. This is for synthetic users ONLY.

Please include your location and the average temperature where you drive.

I am using 15W50 Mobil 1 synthetic. I live in IA, and only drive the car in the spring/summer/fall, usually on days above freezing. Avg summer temperature is around 72 degrees (day/night average), highest high is around 100 . When temperatures are below about 20 F, it is hard starting and will idle terrible for about 10 seconds. I believe this is due to the thick oil. I do several autocrosses during the year, and some spirited driving. The thick oil works great for my driving habits. My fuel economy is worse with the thick oil, probably by about 2-4 mpg average. This current oil change I have about 6k miles and still have 3 bars left on my change indicator, I also have about 4k highway miles on this oil. My previous oil was 10w30 (fossil based).

I also use Redcap but I live in San Diego where it never gets below 50F. Perhaps for winter, you should switch to 5-30 or 10-30. Seems like this would help aleviate your issues upon starting.

Castrol makes a 5-50 Syntec which also might work.

Good luck

I live in San Diego and the previous owner of my car always used 10w-40 synthetic so I am continuing with it. By the way its Mobil 1 stuff.

I always use Valvoline Syntech full Synthetic motor oil. For the winter I am using 10W 30.

Just Changed it today to 5w-30 Mobil 1. It had problems starting in -20c temps.

Peter
1999 318ti 81k

I want to switch to synthetic, but the guys at the dealership it didn't matter, and a guy at the autoparts store said that it could cause problems (fuel pump to go out? I can't remember what it was now because I asked a few months ago) I have 140,000 miles do these guys know what they are talking about or is it just crap?

I Had to edit this in sorry I forgot. I live in Indiana summer around 80 degrees winter around 32 and dealer uses 20w50 oil

I was using mobil1 15w50 , then switched to 5w30 for this winter.

I use redline 20w-50. Superb oil!

There one furmula you forgot......Mobil 1 0w-40, which I use all year round.

I use 15w50 Mobil One.

I dont use any of the weights on the pole I use 0w40

I use Royal Purple 20w50. Good stuff. Live in Los Angeles though so its rarely cold at all... and my version of cold is quite mild.

Upon changing from Mobil to Royal the idle has been smoother and maybe im just insane.. but it just feels like it has a baby amount more of oomph.

I use Castrol Syntec 0w-30. I live near Philly. Great oil in all weather conditions. Never used in -20c though!

That's what I've started running aswell. No problems yet, I'm sending a sample to blackstone after my next oil change.