Which Oil to Use? [Archive] - Bimmerfest - BMW Forums

: Which Oil to Use?

12-05-2008, 10:51 PM
I am new to BMW's but have owned various cars with high performance engines. I have always used a good quality real oil and that seemed to work OK. The previous owner of my car used a high performance oil from Lucas that he had to buy on line and have shipped. Do any of you have any "musts" when it comes to engine oil for your BMW? Are additives of any benifit? Does synthetic make any difference in a car that was designed for real oil?
I have been a fan of Castrol GTX and can't see paying double for an oil like Lucas.

12-06-2008, 11:41 AM
As my Father-in-Law used to say about Beer, There is no bad oil, its just that some may be better than others, depending upon a number of factors. Type of use (street, track, both), how often you change it, type of driving (mostly highway or many short trips). If you change your oil regularly (eg. every 3000 miles) then any good quality "dino" oil like Castrol GTX is just fine. If you want to take advantage of longer oil changes or are planning any track work then a good quality Synthetic Oil is the way to go. This would also help you if you do a lot of stop/go driving or short trips as synthetic additives will hold contaminants in suspension better than dino oils. Mobil-1 is probably the best of the easily available synthetics and Wally Mart usually has the best prices. Use a 10W-30 grade.

For more oil information than you ever wanted to know, go to: http://www.bobistheoilguy.com/

bimmer dot info
12-08-2008, 06:33 AM
If it was run on dino I'd stick with it. Synthetics can cause weak seals to start leaking.
If you change every 3k miles you will be just fine with any quality dino oil.
There are recomendations for the weight in your owners manual. They are based on the temps you expect the car to see.

12-10-2008, 03:46 PM
Bimmer Dot info is correct, changing to Synthetic Oil on a dino oil car might cause some oil seals to leak, but the cause is often mis-understood. Good Synthetic oils have an additive package that will clean the inside of your engine of any sludge and burnt oil deposits. That is why it is often a good idea to change the filter again 1000 miles after switching to synthetic. Quite often on higher mileage cars the oil deposits will gather around the oil seals and the build-up will actually help seal any oil seepage, provided the mechanical wear isn't too severe. These deposits also harden the oil seals. When the Synthetic removes these deposits there can be some leakage as the seal has hardened and cannot flex to accomodate the gap. The good news is that the synthetic additives also contain seal conditioners that will soften hardened seals provided they are not too far gone. Quite often the oil seepage is only temporary and cures itself in time.

12-14-2008, 09:01 AM
I have a 92 535i and for the first 212,000 kms it probably ran on Dino oil. I bought the car when it had 212.000 and I used 15W50 Mobil 1 Extended Performance since. It runs great and have had no leaks, maybe I've been lucky. Today I now have 270,000 kms on it.