I’ve got the day off thanks to working last Saturday so I figured it would be as good a time as any to regale you all with this story from a few months ago (December-January!), and with Shane Moore’s recent GLA45 experience somewhat fresh in your minds. Buckle up kiddos, you’re in for a ride.
The day started out as any winter day in the PNW, cold, wet, and grey. But little did I know that I was about to meet someone that would haunt me for months to come. It was a tale as old as time. Boy meets car. Boy falls in love with car. Boy buys car without a pre-purchase inspection. Now, I’m no spring chicken, so this immediately raised my heckles. But these cars have been very solid so that was probably just me being Abe Simpson.
Enough about me, you’re not here for that. You’re here for the car. Well, it was as if fate and ol’ Murphy were working overtime. The boy was complaining that his new love was being lazy, fighting him, not the car she was when he met her. Normally, I’d say people change over time, but this wasn’t people and it had only been a week. Some say I’ve got a way with stuff like this, so they asked me to see if there was anything I could do. Well, we had a chat, that ride and me, and it turned out the boy was right. She was fighting! But not like he said. Turns out, she was sick and fighting to live! She wanted to be with him, she was trying! But they didn’t exactly speak the same language. That’s fine, it would come in time. Love is stronger than any language barrier.
Well, we got down to talking, that lady and me, and what I learned was that she couldn’t breathe like she used to. But she didn’t know why. Her air filter was new, and she wasn’t that old. She was just barely limping along, running more like an old Harley on gas-turned-varnish. That is to say, she had a dead misfire on two cylinders.
So, like any good mechanic would do in this situation, I ran some tests. And, well, the prognosis wasn’t good. Lung capacity was about half what it should’ve been in two holes, and lower than normal on the other two. That meant it was time for endoscopy. Gentle as I could, I took a little look around, and what I found was not promising. Her insides was looking bad. But there was still hope.
Gold-colored build up like a hooker snorting gold dust. You might even say that’s fitting for a German performance car. Couldn’t tell what that was, all I knew was that it wasn’t right. Then there was the matter of burnt valve seats, the probable cause of the improper breathing. One thing was certain, this lady wasn’t going to make it if we didn’t get her to surgery, pronto.
As many of us know, a boy in love will do just about anything to keep the one he loves, so the decision for him to do the surgery was of course a no-brainer. Not only that, but he didn’t go through chasing her (paying a butt-load of money to buy it) to end up with a big paperweight. So I dove in and got my hands dirty. Don’t worry, I put her under first so she wouldn’t feel anything.
Now, let’s take a step back for a second, build up the dramatic tension some if you will. When I first got to talking to this gal, checking out her vitals and what not, I found something interesting. Something that shouldn’t have been there. At first it seemed innocuous enough, like someone had been in there before and routed some wires in the wrong place. But then I looked closer and realized those wires weren’t even supposed to be there at all. Traced ‘em back, and found they went into a larger harness, and that harness was draped all over like some big parasite. It tapped into a bunch of sensors. Eventually, I found where all those wires came from. It was some unknown black box with no markings on it. Some of you might be wondering what it meant, but you’re a smart bunch so I’m sure some of you have figured it out. Well, it was some cheap piggyback tuner that I found out was commonly sold by all the shadiest, fly-by-night online “tuning” houses, but not sold by a single one with a halfway decent reputation.
This girl here knew it was a bad idea to put garbage like that inside her body, but she said her ex made her do it. Gaslighted her into thinking it would make him love her again, or more, or who knows what. So she did it, afraid of what might happen if he left her, afraid of being alone. She said after a while, she forgot about it and never thought to tell the new boy. He didn’t care though, he didn’t love her for whatever extra pomp that black box was supposed to provide.
But now, her history was coming back to haunt her. Turns out that black box was laced with some bad software. Things weren’t right. Running too lean and hot, timing all outta whack. And that’s why those valves were burnt.
Well, I got in there, made sure the bottom end was happy. But I couldn’t find any sign of that gold-looking stuff. Eventually figured out that was just a trick of camera and light from the endoscope playing off of some carbon build up. In reality, there was nothing abnormal about those pistons. The valves were another story, but those are easy enough, with the right equipment.
I didn’t have the right equipment, so I called up my trusty ol’ machine shop and asked them to take a look and see what they could do. They obliged of course. Took real good care of her too. When they were finished with that head, she looked good as new!
At that point I did what I do best, or, adequately at least, and stitched her back up. But it was after that that the story got real interesting.
Went to fire her up and she let out a holler like you’ve never heard before. She was not happy! “Ow ow ow ow ow ow” real fast, but never really got going under her own power. Then there was a loud pop and she was out. She tried, but she wouldn’t get started, and she sounded off, you know? What had I done? Was timing off? Was that the sound of pistons hitting valves?
After some digging, and rechecking, it turned out that my hunch was right. Timing was off. WAY off. Pistons had hit the valves. But that didn’t make any sense. I followed the service manual perfectly. I’ve replaced pistons in dozens of the non-AMG version of this used in the 205 C-class. I knew what I was doing. Be that as it may, I had to fix what I had apparently done.
So I went about doing just that. That’s when I realized what had happened. The timing marks according to the service manual were wrong. But it was only apparent with the engine mounted in the car.
Do you see the ‘OT’ mark at about the 8 o’clock position on the crank pulley? And the mark on the timing cover it lines up with? That’s how timing is supposed to be set up on this engine. But the service manual says the mark on the timing case is at the 12 o’clock position, which is what I used initially. And there is a mark there that looks exactly like what a timing mark should look like. You can’t see the 12 o’clock mark with the engine in the car, but it’s much more visible than the 8 o’clock mark with the engine out.
I put the effort in and corrected the timing to see if she would run. Amazingly, she did, and she ran well. But she kept on complaining that her timing was off, that is to say, she was setting cam adjustment faults. I did everything I could to fix that; swapping sensors, testing wiring, performing adaptation procedures and software updates, but nothing worked. She just wasn’t right. She was running smooth as ever on all cylinders, but she just couldn’t sprint without complaining about it.
What’s a guy to do in that situation? I did the only thing I could think of and called up her mother (Mercedes). Told her she done fucked up, that she didn’t know how to take care of her own child. Ooh boy did that piss her off. She wasn’t having none of it. All I wanted was for her to admit fault and fix the service manual. That’s it. But she responded saying it wasn’t her fault and that “the document was basically prepared correctly”. Which was horse shit and I damn well knew it. So I gave her more proof, photographic evidence, and got her son involved (Mercedes field technical specialist). He agreed with me. Basically said mom was a narcissistic bitch and said it was her responsibility.
The old lady finally started coming around and getting over herself. So she had me go back in for surgery again to see what was all damaged. Pulled the engine back out and took the head back off. Found all the intake valves were sightly bent, and the guides now had too much play, and the cam adjuster was dead inside. Surprisingly, the pistons all looked fine aside from some very slight cosmetic marks, basically just carbon rubbed off.
This cylinder head doesn’t have guides that can just be replaced, so that meant it needed to be replaced. But that was a problem. You can’t get a cylinder head for these, new or reman, from Mercedes. The only way to get a head, was to get a new engine.
So that’s what we did. And Mercedes paid for it! All because they screwed up the service manual. Moral of the story: check for TDC manually, if you're going to tune do it right, and don’t trust engineers.
The best part? The boy and his new love lived happily ever after.