NewOwner09C300

Hey All,

I have a 2009 C300 that I purchased in June of 2012 with 20K miles. She now has ~42k miles and when i went to get my B service, they told me I need a transmission fluid flush, brake flush, and engine air filter change. My dad says that this is all rubbish and I can wait till 100k miles to get things done. I would like to know what best practices are and if I should go ahead and get it done. My gut is telling me to go ahead and do it. I just am wary of what dealerships say because they're trying to make money at every road. Thank you!

LILBENZ230

The transmission fluid flush was due at 39,000 miles and the brake fluid flush at 2 years. So yes, you should do it. You can change the engine air filter yourself and save some cash.

Your dad is obviously not familiar with the specific maintenance needs of a Mercedes.

NewOwner09C300

Funny Story, he owns an E320 himself so I thought he would know what he's talking about. Would I find this information in the Maintenance/Owner's manual on when these items are due?

MBSebas87

so service b is due at 39k miles??

aznmode

It's recommended by mercedes to keep your car in top working condition. But of course you dont necessarily have to do it. Or at least not exactly in those recommended mileage. Of course you run the risk and you should do it pretty close to it. But just to prove somewhat of a point that you dont necessarily have to do it. My previous 2005 c230 is a good example. It had 121k miles when I traded it in and I never flushed the brake or transmission and I never had any issues with it. Nor did I ever change any belts. I did change the air filter and never drove it crazy though. But what I did is to the extreme and I don't recommend anyone to do the same. I took a risk.

LILBENZ230

The 722.6 transmission in the 2005 C230 (I had one, too) was a totally different story.

Skipping the transmission service and brake fluid flush might save you a little bit now but you could end up paying a lot later.

AkaSigFreak

The 39K Transmission Service IS important. They don't need to do a flush. They can drain the pan and torque converter, replace filter and gasket it your set. The Brake fluid should be drained and replaced every 2 yrs or so because it can hold moisture which can lead to master cylinder corrosion and damage.
Is your father a ASE Certified Mechanic/Certified Mercedes-Benz Technician?
If you want to take a chance and he is willing to pay the repair bill...Go for it.

NewOwner09C300

So what i'm seeing is that a drain and refill is what is truly needed and that the flush is just said so that they can make a ton of money?

What's the difference between a drain and refill vs a flush?

AkaSigFreak

The Flush will cost more because they use more fluid to flush the system. I have been told by multiple friends who are mechanics not to flush a transmission. Just make sure the dealership will drain the Torque Converter when the service is completed. The total amount of fluid used on your invoice should be 8-8.5 quarts IF your car is NOT a 4-Matic. This service can be pricey but is definitely required.

CzchMex

If you read your service manual you will get two tranny fluid changes before 40k. Then after that you don't have to do it anymore. So it is recommended that you do.

The theory behind changing the brake fluid every 2 years is true. If not the master cylinder is very finicky and could prematurely fail if not changed when recommended.

Although this is up to you. But think about the cost of preventative maintenance vs actual repair maintenance costs

tpdietz

Dont flush it. I did my own trans service (check my sig.) because I didn't trust any indy shops to do it correctly. Everybody wanted to flush my trans. Flushing it does not change the filter, and is the "fast" way to do it. There are hundreds of posts regarding the 722.9 trans service.

Pete7874

Can you provide the source of this info?

AFAIK, the trans fluid needs to be changed every 39/40K miles, so if you did it at 40K, you should do it at 80K and at 120K, and so on...

tpdietz

This is correct. The service manual sent out with the 2008 w204 recommended a single change at 39k miles. In 2009 and the following years Mercedes changed the recommended servie interval to every 39k miles.

Pete7874

Right. I'm still wondering why CzchMex thinks the car is supposed to have two trans fluid changes done before 40K.

CzchMex

I apologize. I went back and checked and was wrong. It's just the once

Acapulco Bill

Since NewOwner09C300's W204 is a MY2009, if the transmission/torque convertor fluid change is done at an MB dealer, then get the free TCU software update for the 7G. Makes a difference, although the stupid Adaptive Learning will start to degrade performance at the first traffic light.

NewOwner09C300

What is the TCU Software update?? And is it really needed? I spoke to my service guy and he said i just need the fluid change and not a flush, those other guys were just trying to get me to pay for the service. I'm not going to do it at the dealership too because I can't afford to pay an arm and a leg for it haha.

Acapulco Bill

MY2008 - 2010 and perhaps the first MY2011 have a FREE TCU software update that can be performed anytime the Star diagnostic system is connected to the W204 (as in an A or B service, or transmission fluid change).

The official MB 7G fluid change, "required" at 39k miles, means draining both the transmission case AND the torque convertor. Refill should take 9 (liters/quarts?) and NOT only 7, which means just the casing was drained. The Draconian refill procedure (as stupid as the 7G's Adaptive Learning) requires running the transmission until it reaches a specific temperature, then checking the fluid level with an access plate half-way off before trying to slam and bolt it shut, must have been copied from Rube Goldberg's last will and testament.

The 7G is never to be flushed. Period.