I have about 2,000 miles on my truck and I was wondering when it was a good time for an engine oil change. I realize most people are changing at 5,000mile intervals. This is the interval I usually go with, but MOBIL sells oil that is good for 15,000miles. I also have a BMW and they recommend oil changes every 15,000miles!!! And im sure if they are confident in their oil/engine that they are recommending oil changes at such high miles. (they use Castrol Syn Oil). My questions are:

1) I want to switch to syn. oil when I reach 5,000miles. What brand should I go with? I was thinking of Mobil 1 (15,000mile interval) or Royal Purple

2) Tranny oil. The manual says every other oil changes so Im guessing every 10,000 miles. I was also thinking of Mobil 1 or Royal Purple

3) Finally differential oil. When I used to have a Subaru WRX, I used to change the diff oils every 10,000miles. Also, should I do both front and back diffs? I was thinking of using Mobil 1 or Royal Purple.

p.s.-There were no topics for chaning diff oils/tranny oils so dont flame please. I know the rules of forums because I belong to four other forums. Thanks

 

Welcome to FTE!

Check out the Oil and Lubrication page further down on the Fourm list, you will find lots of information.

The days of the 2000 mile engine oil change and the 10-15K mi tranny fluid change are long, long gone. Technology and advances in over all performance have changed everything, including oils.

Follow the manual on this, which is always the best advice. 5000 miles for the motor oil, 100,000 for the differentials, and 100,000 for the tranny (I reccomend 50,000 mi). You can change the stuff as often as you want, but keep in mind that you'll be tossing a ton of money away for nothing.

If you want to talk oils, RP is really overhyped for the quality of oil. Motorcraft 5w20 Semi Syn turns out much better UOA's at fractions of the cost.

You could use M1, but the 15000 mi stuff doesn't come in a 5w20, only the 7500mi stuff does. The 5w20 M1 doesn't carry the 15000 mile warranty, just the 5w30.

Any oil that has the latest API rating (SM) will do an over the top job on protecting your engine, even the house brands. Motorcraft 5w20 is one of the best oils on the shelf and can be had for decent prices at your local walmart. I will also reccomend the use of the MC FL-820S oil filter available at Walmart over the orange grenade can of death (fram) any day of the week and twice on sunday.

 

Thanks for the advice. I appreciate it. I would def hold off on changing the diff/tranny oils until I hit 50k. And I will most likely go with Mobil1 7,500 mile Syn Oil and change it every 5,000miles.Appreciate it

 

the mobil 7500 oil is not synthetic but rather semi synthetic. the bmw 15k change is already known to be bad. look at the bmw forums. i would not go 15k on the oil.

 

the only bad thing I have experienced/know is the fact that BMW likes to underfill their engine oil. I had the engine oil light come on, added a quart of synthetic oil, and havnt had a problem in over a year. I have asked many members and technicians and they all say the same thing. BMW would not warranty their engines if they knew that oil changes at 15,000 would make them lose money.