2QUIK4U

Yesterday I went to a Mobil 1 oil change center in the area to have the first oil change on my C55. I was going to go to dealership, but they weren't able to get me in until late next week.

Anyways, I remember seeing the guy put 5W30 Synthetic in car. However, after doing a little bit of research, I realized that Mercedes recommends 0W40 oil for my car. I'm a little concerned and am wondering if I need to go back and have them put the recommended oil in my car. Could this potentially affect my warranty or be detrimental to the engine? What would you do?

Fifth Ring

First, check your manual and see if 5W30 is within the recommended range. If it is not, you could ask for a refill. Keep in mind that "Mobil 1" can mean a LOT of different things. Some weights of M1 are approved for use while others are not.

Ironically, the biggest scofflaws are dealers. I have heard MANY stories of dealers using junk oil -- not meeting the manufacturer's standards for quality or weight.

whoover

Use of 5W30 is not approved for AMG engines, and will void the warranty. Oil must be listed in 229.5. As far as I know, the only Mobil1 that qualifies is 0W-40. It's safest to look for "MB 229.5" on the package when buying quarts for top up, and insisting that any shop really has a 229.5 oil. They also have to use the fleece filter. Failure to do so also voids the warranty.

kjb55

I would recommend changing it - and sooner rather than later. The new spec as of May 15, 2006 is 5W-40 Mobil1 meeting spec 229.51, with a fleece OEM filter.

Fifth Ring

I wouldn't panic. There were many horror stories on the Audiworld message boards where dealers put over-weight, junk dino oil into Audi turbo motors. No failures were ultimately reported. Turbos are brutal on oil, and unlike our supercharged motors, they are far more likely to toast bad oil. Turbos are also very sensitive to overly thick oil b/c they have small oil passages that need to be fed at start-up.

So, I would find it VERY unlikely that a good synthetic would cause problems until you were thousands of miles down the road. Keep in mind that the oil rating set by Benz is for a 10,000 mile (or more) life; so the designation of 229.51 really comes into play many, many miles into the oil's life. As long as the weight (flow) is within reason, I'd have it replaced, but at my convenience.

To put it in context, several Audi owners were given 20W50 motor oil (nonsynthetic) by dealers; and in one case, the dealer insisted that the oil was consistent with Audi standards. The owner had to go up the chain to Audi of America to get the dealer to reverse its position.

whoover

229.51 does not supercede 229.5. They are different specs. You can see here:

http://www4.mercedes-benz.com/e/cars...en/N2F5D7.html

that (for example) you can use 229.5 or 229.51 oil in a current E200 Kompressor, 229.5 but not 229.51 in an E63 and 229.51 but not 229.5 in an E320 CDI. In general, 229.51 is a diesel engine spec.

As far as I know, the C55 is still 229.5 and 229.51 does not apply.

I wouldn't panic, but I would get the right oil and filter in the engine if it were mine.

Catapult

Here is another link with Mercedes engine oil recommendations

http://www.whnet.com/4x4/oil.html

2QUIK4U

I am thoroughly confused at this point. Today, I called the Mobil 1 center that did the oil change yesterday and they said that they were willing to change it back to 0W40. So I go to the service center and speak with the guy. In mean time he says that he spoke to one of the service managers at the Mercedes dealership (Park Place in Dallas) and according to him, Mercedes recommends 0W40, but as long as Mobil 1 synthetic is in the vehicle, they would not void the warranty. I then decided to call a mercedes service manager myself and he said that although they recommend 0W40, 5W30 is fine as well. Since the guy at the oil change place was reluctant to change it and based on what the dealership guy told me, I said fine and decided to leave the 5W30 in there.

However, I am a little alarmed because on the website that you guys posted (i.e. http://www.whnet.com/4x4/oil.html) it specifically says : "Note: 5W-30 oil viscosity is not approved for use in all AMG engines." So I am wondering if the service manager doesn't know what he is talking about or who I should listen to.

This is really becoming a hassle and I wish that it wouldn't have to be so complicated.

kjb55

The diesel reference at the link provided is mis-leading. 203.076 is the C55 AMG. Clearly listed in the attached factory TSB is the latest spec calling for 5W-40. Bottom line is that the shop used the wrong oil, and given the possibility of thinner oil at operating temperature not providing the correct lubrication, I'd make it my first priority. The 5w is the cold rating, the 40 is the hot rating.

While you're at it, are you sure they are using the fleece oil filter with new o-rings?. If they are sucking the oil out, know that you'll have 1.5qts of old oil remaining. If they are draining it, are they draining from both locations? And are they replacing the crush washers?

whoover

Thanks for the update.

As I said, I hadn't heard that C55's can now use 229.51, but it's good to know. And although 229.51 did originate as a diesel spec, the example I cited did include the gasoline E200K as a 229.5/229.51 engine.

Fifth Ring

As I noted above, dealerships are often the worst violators of manufacturer specifications. You should find MB documentation showing the required oil type and bring that to the shop that did the change. Unless they can show you paperwork to the contrary, you win.

And it's not about voiding the warranty. There's a REASON it voids the warranty. It's not the right oil!