[Starscream]

Lifetime oil just doesn't sit well with me,
My 3 series just hit 30k miles and I wanted the diff oil out,

I replaced the gears in my M to 4.10's a few months back,
See here ----> M Diff 4.10 Install Thread
I was so shocked how dark the oil was in my M after only 6000 miles!

So I decided 30K was enough for the diff in the 3 series,
Thankfully my 3 has a non welded shut diff, so getting the oil out wasn't "too" much of a hassle,

I'm sure most of you are aware the diff's (on the non M's) do not have a drain plug, Only a fill plug, and what I've read from people is they use a suction device to remove the oil from the diff,
This also wasn't sitting well with me as there's no way your going to get all the oil out by sucking it,
So I actually removed the rear cover,
It wasn't that hard, One big bolt on the top right ear of the cover, and I think 8 or so smaller bolts holding the cover on,
with the larger bolt out of the top mounting ear of the diff you can actually turn the diff down slightly to drain the oil,
I jacked the front of the car up so it was on a reverse angle and drained the diff completely,

I took two oil samples, One of which will go to Castrol and the other I keep as a spare,
I send ALL my oil's to Castrol for analysis, Every oil change of any kind,
Gives me peace of mind,
I shall post the findings of this 30k Castrol SAF-XO oil when I get the report back,
I'm sure its fine, but from now on I am going to change the oil annually with Red-Line 75w-90,
Thats what I used this time, and thats the clean oil in the third container,

Now obviously just because oil is dirty doesn't mean its no good, the picture comparing the two colors of 30k oil and fresh oil is simply for reference,

If anyone intends to keep their cars or like me is just a little obsessed with preventive maintenance I'd suggest a change,
It wasn't that hard, and to re-fill the diff I used the fluid transfer pump from Bav Auto



Here is some pics of the oil that came out with 30K miles on it next to fresh Red-Line 75w-90 oil





Sample will be off to Castrol Monday and I'll update the thread when I get the report back

[lopealle]

hold on and time out. first off what is a diff. and where is it located. my car also has like 31k and i just dont believe in the oil chabge every 15k either. can u tell what i need to do so i can do the same thing. and how much does it cost to send the oil off for analysis?

[Joshboody]

The BMW diff oil is black to begin with I hope. Did you replace the seal? How long between your engine oil changes... and what has castrol reported back in the past; do they compare to new oil?

[ENINTY]

I beg to differ on your comment that a suction device can't remove all the oil from the diff. I use a pneumatic oil excavator that removes all the oil. If you make the correct length of suction tube you can get all of it. It's a lot less trouble than removing the rear diff and rear diff mount and risking a bad seal once you put it all back together. If the seal is bad, then you've blown $60 of diff oil because you have to start all over again.

Just my 2 cents.

[bayerischeperformance]

thats friction material and small metal shavings wouldnt call it anything out of the ordinary

[Park2670]

Had my front and rear diff oils changed at 40k. As well as the coolant, and transfer case oil. Cant hurt it at all. But im pretty sure bmws stock diff oil is very dark to begin with.

[jemanner]

Agreed. "Lifetime" lubricants do not cut it. In my opinion the "lifetime" of the vehicle will certainly be extended with periodic fluid changes, called for or not. Possibly down the road with confirming analysis, but my first oil change is certainly not going to be 12-15K as determined by the CBS computer. At the very least, one should have these lubricants checked by a lab. They pick up contaminates with miles, especially during the break-in, and in my opinion this shortens component life. In a nutshell, cheap insurance. BMW, or any manufacturer, wishes to get customers past the warranty period with few issues, but lets be honest, service and repairs are a dealer cash cow.

[Starscream]

SAF-XO shouldn't be any darker than SAF-XJ which I used for my M and that was even lighter than the red-line shown here,
This I will look into but I actually remember them changing the color in the past year or two so for color you could be right,

again not to say dirty oil means its not doing its job, I'm sure the tests will come back fine,
as I said I will let you guys know the results,

for analysis I use Castrol Labcheck
http://www.castrol.com/castrol/gener...tentId=6005538

www.labcheckonline.com

[Park2670]

All we know is that your cars will last much longer than the ones following the BMW recommended changes...

[Starscream]

I know I over change the oil, and other filters, I go well below the recommended intervals,

Some might call it obsessive,

But to tell you the truth I enjoy it and like to keep the car running at its best,

[jemanner]

What is the fee for a standard Castrol Labcheck? Have been using Blackstone in the past, but with purchasing a BMW, and most likely using Castrol (versus Mobil 1) products, it might be wise to use their anaylsis service also.

[Starscream]

Originally Posted by jemanner

What is the fee for a standard Castrol Labcheck? Have been using Blackstone in the past, but with purchasing a BMW, and most likely using Castrol (versus Mobil 1) products, it might be wise to use their anaylsis service also.

contact them and see,
I had a friend setup my account through his job and I get a discount so your price would most probably be different,

[jemanner]

Originally Posted by Starscream

I know I over change the oil, and other filters, I go well below the recommended intervals,

Some might call it obsessive,

But to tell you the truth I enjoy it and like to keep the car running at its best,

Before the day of most on this forum, but can recall my first VW Beetle, circa approximately 1966, whereas an early-on engine oil and transmission gear lube change was mandatory, somewhere around 500 miles. Admittedly, long before the day of synthetics. Also, the Beetle did not employ an oil filter, only a screen to catch large debris. However, a 100,000+ teardown showed the crankshaft journals to be at factory specs. Frequent oil changes DO make a difference! If for no other reason, to prolong the life of the lengthy and multiple timing chains in the typical BMW engine. I wil confess, if I planned to trade in shortly after warranty expiration, would probably only adhere to the minimum maintenance schedule. This also is why my preference is a factory-new machine, to give it TLC from day one.

[Starscream]

Originally Posted by jemanner

Before the day of most on this forum, but can recall my first VW Beetle, circa approximately 1966, whereas an early-on engine oil and transmission gear lube change was mandatory, somewhere around 500 miles. Admittedly, long before the day of synthetics. Also, the Beetle did not employ an oil filter, only a screen to catch large debris. However, a 100,000+ teardown showed the crankshaft journals to be at factory specs. Frequent oil changes DO make a difference! If for no other reason, to prolong the life of the lenghty and multiple timing chains in the typical BMW engine. I wil confess, if I planned to trade in shortly after warranty expiration, would probably only adhere to the minimum maintenance schedule. This also why my preference is a factory-new machine, to give it TLC from day one.

Yup mine get a lot of TLC,
I bought both of mine so maintenance is a big key in my cars, also a track record of the entire car since new with receipts and oil analysis makes future buyers of my cars happy