what engine oil to put in because i dont know if its syntec or normal?

[träumer]

since i got the car from a stealer how would i know when its time for an oil change if it is running on synthetic or normall.is there a way you can tell the difference between synthetic oil and normal.and if i put in synthetic and it had normal will it blow the seals.

[Bear]

It is impossible to tell if the oil is synthetic or petroleum based (Dino Oil)) just by looking at it. What model/engine and how many miles on her? I would change my petroleum based oil every 3,000 miles (that's hust me)and my synthetic at 15,000 mile intervals (I do change the filter every 5,000 miles). Adding petroleum based oil to synthetic or the other wqay around does not matter as you are not going to blow any seals. Depending on where you live and the climate any where between 10W40 and 20 (or 15)W50 is good.

[träumer]

thanks bear i live in sunny humid miami florida. i have 87 325e coupe with 172,690 miles and the odo is broke.who knows how much miles is under the hood? i would like to use a synthetic oil like castrol or mobil 1. thanks bear i guess i will go with synth but what weight should i use?

[Bear]

I live in SE Virginia and occassionally make it to Bonita Springs. I use MOBIL-1 15W50 other companies have 20W50 but makes no difference. I ran my oil change schedule (one year or 15,000 miles with filter every 5,000 past the TECH guys at MOBIL and they said no problem). I am car sitting the kids 1990 325ic and that is the schedule we use, I also have a 1988 750il and the same schedule applies. After over 156,000 on the 325 and 135,000 ont the 750 I have no leaks and no problems.