Suddenly needs oil, then it doesn't?
Thread Starter
Senior Member
Joined: Jan 2010
Posts: 312
Likes: 106
From: DFW area in TEXAS! 🤠
2018 S450 4Matic, 2021 Toyota Tundra, 2010 GL350 (sold)
Suddenly needs oil, then it doesn't?
Hi again everyone! I am now cancer free - for those that remember me.
I am having an issue that is alarming with my 2018 S450 4Matic with the M276 engine.
The DAY BEFORE SURGERY (of course), we drove five hours to Houston and when we were almost there I got a message that I should check the oil at my next stop. I figured maybe it was slightly low so I went to O'Reilly's to get some Euro oil.
TOOK TWO QUARTS!
Here's the weird part.. we check the oil before a long trip like that and it was fine.
When I bought a German car, I put an old but clean light colored rug down in the garage under the S450. There isn't a single drop of oil to be seen anywhere in around 12,000 miles.
I thought it was just a fluke so I made a mental note and continued to check the oil.
A couple of months later we drove about 90 minutes to a small town to have dinner. Same message. This time only needed one quart. This was a little over a month ago.
Have since been on long drives and there hasn't been an issue.
Sometimes after I'm driving 20 minutes or so, I can smell oil when I get out of the car. We never smell anything in the cabin. When I look under the car immediately and after an hour or two - no oil leaks I have every found.
**Need some advice on what I should do.**
This concerns me to the point that I think maybe I should get a different car. I like the EQS580, but... it's not an S-Class.
I am having an issue that is alarming with my 2018 S450 4Matic with the M276 engine.
The DAY BEFORE SURGERY (of course), we drove five hours to Houston and when we were almost there I got a message that I should check the oil at my next stop. I figured maybe it was slightly low so I went to O'Reilly's to get some Euro oil.
TOOK TWO QUARTS!
Here's the weird part.. we check the oil before a long trip like that and it was fine.
When I bought a German car, I put an old but clean light colored rug down in the garage under the S450. There isn't a single drop of oil to be seen anywhere in around 12,000 miles.
I thought it was just a fluke so I made a mental note and continued to check the oil.
A couple of months later we drove about 90 minutes to a small town to have dinner. Same message. This time only needed one quart. This was a little over a month ago.
Have since been on long drives and there hasn't been an issue.
Sometimes after I'm driving 20 minutes or so, I can smell oil when I get out of the car. We never smell anything in the cabin. When I look under the car immediately and after an hour or two - no oil leaks I have every found.
**Need some advice on what I should do.**
This concerns me to the point that I think maybe I should get a different car. I like the EQS580, but... it's not an S-Class.
Last edited by bdunn; Oct 19, 2025 at 04:00 PM. Reason: Forgot something important
Super Member
Joined: Jun 2025
Posts: 784
Likes: 249
From: USA
This is a classic symptom of a failed PCV valve (breather cover) on your M276 engine. It sucks oil into the engine during long highway drives, which is why you're low with no leaks. A mechanic familiar with Mercedes will know this issue immediately. Get that replaced; it should solve the problem.
Thread Starter
Senior Member
Joined: Jan 2010
Posts: 312
Likes: 106
From: DFW area in TEXAS! 🤠
2018 S450 4Matic, 2021 Toyota Tundra, 2010 GL350 (sold)
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