Oil change frequency

Maintenance/Repairs
1

I bought a used (formerly corporate lease) 2006 BMW 325 xi with 16,000 miles on it last year. It now has about 25,000 miles on it.



My question is this: Under the 4 year warranty, regularly scheduled oil changes are done by the dealer at no charge every 15,000 miles. That seems to be way too long between oil/filter changes. I’m used to doing it at least every 5,000 miles with my former cars. All of the BMW techs I talk to say that 15K is the standard linterval for oil changes, and in fact the car will turn on

a dash light every 15K to alert me when it’s time. Should I listen to them and do it only every 15K, or pay for it myself and do it every 5K??? Also, I plan to keep the car beyond the free service warranty period. What do you think?

2

Regardless of what BMW or the techs say, I would chnage it twice as often, every 7500 miles. And I would gladly pay for the extra oil and filter change myself.

If you only drive on the highway and cross-country, this interval would be acceptable in my opinion.

BMW clearly does not umderstand stop and go driving in Minnesota winters.

3

Yeah, traffic is always light and it never gets cold in Germany…:wink:

4

BMW also demands you use “German Castrol” synthetic oil to achieve that 15,000 mile service interval.

I agree with you, if you are going to keep it forever, change the oil every 5000 miles with whatever quality motor oil you like. Cut the cord between you and the dealer, you will NEVER get out of there “for free”, find a good, independent mechanic to maintain your car.

5

Here is some good, comprehensive info from bimmer.com. A little more technical than some folks will want to read, but very good info:

  1. All new BMW’s require synthetic. As far as weight, only certain production dates of M3’s and M5’s require the use of Castrol TWS 10w-60.

  2. The Factory BMW Synth 5w-30 is a version of Castrol TXT Softect sold overseas. A few important things about the BMW oil a) it is a Group III hydrocracked oil which cannot be called synthetic in Europe, b) it is a heavy 30 weight (30 weight can run from 9.3-12.5cst@100c, the BMW oil is about 12.2cst), c) it is a ACEA A3 oil which means that it is approved for longer change intervals and has a HTHS (High Tempurature High Shear) measured at 150c of greater than 3.5.

  3. In the US, the only Group IV PAO Synthetics that are available are 1) Mobil 1, 2) Amsoil (but not the Xl-7500), 3) Royal Purple, and 4) German Castrol 0w-30 (it has the red label and says on the back, "Made in Germany). Redline is a Group V PolyEster based oil. All other Castrol, Quaker State, Pennzoil, Valvoline “synthetics” are a Group III hydrocracked oil. It is debated how much better Group IV base oils are than group III, but generally they are considered better.

  4. When looking for oil for any BMW that does not require Castrol TWS 10w-60, you want to purchase an oil that has either/both of the following ratings, a) ACEA A3, or b) BMW LL-98 or LL-01.

  5. Note that Mobil 1 0w-30, 5w-30, and 10w-30 are NOT ACEA A3 or BMW LL approved oils. This is because they all are thin 30 weight oils (approximately 9.8-10 CST@ 100c) and have HTHS of approximately 3.1. Mobil 1 0w-40 and 15w-50 are A3 rated and the Ow-40 is BMW LL-01 approved. For 99% of climates and users 0w-40 or 5w-40 is the appropriate grade. There are some 0w-30 and 5w-30 oils (like the BMW 5w-30) that are forumlated on the heavier end of the 30 weight scale and are accordingly rated A3. These oils will work well also. LOOK FOR THAT ACEA A3 rating. If the oil doesn’t have it, pass on it.

  6. Some people seem confused about how oil thickness is measured. The first number (0W, 5w, 10w, 15w, etc) is a measurement of how thick the oil is at tempuratures of -35c- -20c (depends on the grade). The lower this first number the thinner the oil is at LOW tempuratures. The second number (30, 40, 50) refers to oil thickness at 100c (operating tempurature). 30 weight can be from 9.3-12.5 cst, 40 weight from 12.6-16.2 cst, 50 weight from 16.3-22cst (approximate). So you can have two oils, one called a 5w-30 (i.e. bmw oil) another 0w-40 (Mobil 1) that are very similar thicknesses at operating tempurature. Compare this to Mobil 1 Xw-30 which is close to a 20 weight oil at 100c. For more information here is a link with exact numbers http://www.bobistheoilguy.com/visc.html

  7. BMW’s recommended interval of 12,000-15,000 miles is to long. Used oil analysis has shown the BMW oil is generally depleted at 10,000 miles. Running it longer results in excess wear. It is highly recommended that you change your oil once between each BMW recommended interval (approx 7000-7500 miles). If you want to run your oil the BMW recommended interval, I would suggest that you use Mobil 1 0w-40 or Amsoil 5w-40 and change the oil filter at 7500 miles. I would encourage a full oil change at 7500 if you want your engine to last.

6

From a fellow tribologist, thanks for the detailed explanation. So with a BMW we have a stringent viscosity requirement, which can be met with a good real synthetic, as well as additive depletion which is a function of driving style. Additive depletion and contamination generally drives the drain interval.

In Germany there are 2 green parties who hold the balance of power in government. The Germans are obsessed with recycling oil and minimizing waste oil. Both BMW and Volkswagen have excessively long drain intervals, but German cars are normally sold or scrapped long before those in the US.

As per other posts, I would change oil and filter in my BMW more frequently, unless all my driving was long distance highway at moderate speeds.

7

As one of the veterans of this forum astutely states, “Oil is cheap–Engines are expensive”, and he also has wisely reminded us that the main idea is to extend the life of your engine, not to extend the time period between oil changes.

As I frequently advise people–no car ever suffered from being maintained better than the manufacturer recommends.

8

“German cars are normally sold or scrapped long before those in the US.”

I know for a fact that it is standard for German taxi drivers to buy new every few years and sell, NOT SCRAP, the used car. That’s high mileage and stop and go driving. Additionally I was able to find thousands of high mileage cars (~200000 km) here: http://eng.autoscout24.com/