I purchase my S350 new 5 years ago, it has 74K miles on it now, and it has had many issues.

Last month my exhaust had a strong ammonia smell, the check engine light came on, and some smoke was coming from the exhaust. The dealer replaced most of the Adblue parts, including the Heater and Metering Valve, and thought that would take care of the issue. I knew that the Heater had not been working for some time, but since the car was not driven in cold weather, I had not agreed to have it replaced until last month. After completing this repair, the dealer also recommended replacing the SCR Catalyst and Rear Nox Sensor (Quote: $4,355.29) since it was clogged up with Adblue according to him - I declined to see if the issue was resolved with the initial repair. Unfortunately, the smell was still there, and the check engine light came back on!

After reading my Warranty Book, I called the dealer back earlier this week and told him that my Warranty Book states that the SCR Catalyst is covered under warranty for 8 years or 80K miles (page 28 & 29 S350 Warranty Book), and asked why I was quoted $4,355.29 to get it fixed.

Dealer did not get back to me for two days, but today I was told that since I had not had my Heater fixed earlier, it might have caused the damage to the SCR Catalyst, and therefore the warranty might not apply! The dealer did get Mercedes Corporate involved, and I was offered the following:

My dealer will replace the SCR Catalyst, and send the old one to Mercedes for evaluation. If they determine that I am at fault for not replacing the Heater earlier, I will have to pay a discounted price for the repair (around $3,500.00). If they determine that I am not at fault, they will pay. It may take them up to 3 months to make this determination! The representative told me he was 75% certain that they would pay for the repair, and the dealer thought my chances were even better.

As an alternative I can sell my car, and they would pay $5,000.00 toward a new S-Class at any US dealer - on top of the best negotiated price.

I am not only disappointed in the quality issues with my car, but also with the way that Mercedes is dealing with its clients, and standing behind its products! Sadly, I don't think that I will ever purchase another Mercedes again. My question is: Should I get this repair done, and hope that I won't have to pay for it? Or should I just get rid of the car, and look for something else to purchase - in order to avoid more issues in the future!?

Thank you,

Christian

 

The heater issue will happen again and there are companies that make metal heaters instead of plastic ones that last longer, but a dealer wont install them.

The SCR in my car lasted 165k, which isnt bad. But, the problem is it went bad without any codes. I believe I have an injector issue. Other people have gone through a few.

For $1200 there are companies that will make a tune to delete all that stuff, plus whatever to make a delete pipe. It seems like everyone who has done that is happy with their cars now, expect maybe for the fact they now smell like diesels. But no more adblue, or other SCR issues.

Also I hope you are changing the oil more often than is recommended, like every 5k.