…still in it.

My Mercedes-Benz is a 2012 E350 Bluetec…a diesel…and my dream come true car. It’s the car I’ve wanted since I was a teenage boy and an uncle came for a visit driving his brand new Mercedes 220D. So I take care of it, not just because it cost me a bundle, but because it’s my dream come true car. Actually I’ve always taken care of all my cars, even the junkers I drove when I had no money. The Automobile is a miracle machine, a magic carpet that gives you all the new horizons you can find on every road you’ve haven’t yet been down. You take care of a thing that gives you so much wonder. You love it back.

A religion I’ve had since my first car, the 1973 Ford Pinto, is changing the oil more frequently than the factory says. Nothing kills a good engine faster than not giving it fresh lubricating oil regularly, and no single thing you can do for it will extend its life more than doing it more often. For American cars you take the recommended interval between oil changes as a bare minimum. I changed the oil in the Pinto every 2k. They will tell you it’s a waste of money but it isn’t. When I finally had to give up the Pinto it was because everything But the engine was coming apart. That’s how they used to build them in Detroit. I got 136k miles out of that car and when I watched it go away you could still pop off the top valve cover and it looked factory new in there. The steering wheel was cracked, as were the vinyl seat covers and the dashboard padding, and the shift stick would sometimes pop out of its base like a gecko’s tail in my hand. But that engine, that little 1600cc one barrel carburetor four calendar engine that would even run smoothly on sub regular gasoline, still ran as strong as the day I took the car home.

When I got the diesel I knew it was even more important to stay on top of the oil changes due to a diesel’s high compression and really, I mean Really dirty blow-by. Daimler says change the oil every 10k, and that’s probably reasonable given that they put a nine liter reservoir in those engines, and specify type 1 synthetic oil. I’ve changed mine every 5k and have been told repeatedly that’s a waste of money. My response is it’s cheaper than a new engine. But recently I read a post on one of the Mercedes forums to the effect that the new Bluetecs may need their oil changed as frequently as every 3k due to how the emissions systems heat the oil up to higher than usual temperatures and recent changes to the oil spec. When I took the Mercedes home it specified Mobile type 1 5w-40 diesel blend. Then they stopped making that and MBUSA started putting a 5w-30 type 1 in during routine service visits. I was skeptical. If the engines are running hot 30 weight may not be good enough. Eventually bought my own oil extractor so I could do my own between servicing oil changes, and began buying oil from a supplier who could get me the same stuff they put into them over in Germany, which is still 5w-40.

The extractor allows you to pull the old oil out of the engine from the dipstick pipe. It sounds strange and counter intuitive, but that’s actually the better way to do it on a Mercedes because (so I’m told) the drain plug at the bottom of the engine doesn’t actually allow all the oil to drain out. It’s a bit higher up on the block than would be needed to completely drain the engine, to prevent (again, so I’m told) all the oil exiting the engine in case the plug ever falls out while you’re driving, leaving enough in there to get you somewhere safe when the console display starts screaming at you that the oil is almost gone. Using an extractor gets it all out and it’s easier to use than it sounds. Run the engine until it’s at temperature (I take a quick drive up I-83 and back), then pop the hood and pull off the engine cover. The oil filter is right there and its easy peesy to pop the cap off (you definitely need the cap wrench though) and just let it hang in there and drain. With the extractor you basically thread a plastic tube down the dipstick pipe and connect the other end to what looks like a tank with a pump attached. Then you pump enough air out of the tank to get the oil to start flowing up the tube and into the tank. Once that starts the siphon effect keeps it going so you don’t have to keep pumping. There is a pressure relief button you press from time to time to let air out of the tank.

It’s a nice arrangement. You don’t have to get under the car at all. The only thing is it’s slow…about 20-30 minutes to get it all out. But you know when it’s all out because you actually hear a slurping sound, like sucking on a straw when the glass is nearly empty, and the siphon breaks and the oil stops flowing. By then the oil filter has drained and you can put the new one on. Which is where, more familiar as I was with changing the oil in American cars, it became strange.

See…in the Pinto and my other cars, including the Geo Prism which was a Toyota Corolla under the skin, and the Honda Accord, the filter was in its own can under the engine and you just unscrewed it and screwed on a new one. In the Mercedes, like other European cars, the filter is in a permanent can and you unscrew the cap off the can and pull out and replace the filter inside. And as you might expect (being used to The American Way) the cap is very…strange. Here’s what mine looks like…

If you can picture it, the filter fits over that structure in the middle of the cap. When you screw the whole thing down, a metal tube feeding oil into the filter pushes into the filter and over the part of that structure where it’s narrowed to a tip, up to the mid point where it gets its widest. Oil pushes through that, into the filter and out and back down onto a trough where there’s a drain back down, presumably to the oil pan. But look at that thing. First time I pulled mine off I was completely bewildered as to what the hell that structure at the end, where it narrows to a little tip with a little o ring at the end did (there is another much larger o ring near the top of the cap). It pushes down into a tube within the feed tube and seals it off and I could not for the life of me figure out what it was for. So I did a little digging online and discovered that it’s Yet Another Drain back to the oil pan, for when you are changing filters. The German engineers figuring that having that other drain would make draining the filter go faster. And it’s not a Daimler thing either. BMW does it too. And I know this because when I did my last oil change that center structure came off and I thought I’d broken it but I wasn’t sure. It seemed like it might have been a press fit. So I frantically Googled around for info about whether that center structure comes off and yes, it does and yes it’s just press fitted onto a bunch of tabs at the base. Panic Attack Over. But I mail ordered another cap just in case I ever do break it and now I can’t drive the car anywhere, like to the dealer to get another one.

The engine takes nine liters of oil. That works out to about nine and a half quarts and it’s one of those things that really impresses me about German engineering: they specify a change interval and put enough oil in the engine to make it reasonable, instead of just barely minimal. But the way the process works is after you’ve put the new filter in place you don’t fill the engine up with all nine liters. Put in eight and start it up, let it run for a bit so you’ve got the filter charged, then stop and check the dipstick and top it off. So there’s another little difficulty. Here’s the dipstick they gave me…

Trying to see where the oil level is when you’ve got a fresh pan of honey oil in there is really Really hard because the plastic that thing’s made of is shiny and you can’t tell where the oil actually is on there if it’s completely clean and new. For example…

This is after a week of driving on the new oil. Because it’s a diesel the oil I just put in there is already getting mighty dirty. But look at that. Can you see where the oil level is on that thing? It’s hard, but it’s just shy of the screw on the right. You pretty much just have to trust that the nine liters you bought is exactly right and you really did get all the old stuff out and there wasn’t any extra left in there to put you over the maximum…which is scary because over filling the oil pan can damage the engine.

Anyway…the car has just under 115k on it…next routine servicing is at 120k and I’ll probably tell them to skip the oil change because I’m doing it myself now with the 5w-40 which was the spec when I bought the car, or if they’re willing use the oil I provide.