June 19

2008 Mercedes ML320 Intake Manifold Repair

Podcast2018, Mercedes


Mark: Hi, it's Mark from Top Local. We're here with Bernie Pawlik. Pawlik Automotive in Vancouver and we're doing the Pawlik Automotive Podcast this morning. How you doing, Bernie?

Bernie: Doing very well, Mark.

Mark: So we're going to talk about a diesel an ML320 Mercedes Benz. There was a problem with the intake manifold. What is going on with this fine German automobile? 

Bernie: Well, what was going on with this ... I won't try the German but what was going on with this vehicle, it came to our shop with a massive oil leak which we diagnosed to be coming from a couple of spots, the rear crankshaft seal and also the engine oil cooler seals. Now the engine oil cooler seals are located in the valley right at the V6 engine so the valley is the section between the two cylinder banks. The oil cooler is located is right in the very bottom. And there's a lot of items that need to be removed to get at the oil cooler such as the intake manifold being among them. 

Mark: So if it came in with an oil leak, again I guess, why are we talking about intake manifolds? 

Bernie: Well we're talking about intake manifolds because there's an actuator in the intake manifolds that causes problems. They have two ... it's an actuator that moves a flap back and forth inside of each intake runner and it can vary the size of the intake or the intake port size. And it's tuned for basically different running conditions so at certain speeds you want different kind of flows through the intake manifold for performance. And this intake runner, these things plug up. They wear out. And I'm going to put a video on which we can look at right now which will explain it almost better than my discussion here. So let's start with the video of the bad runner. Now you can see this, correct?

Mark: Yep.

Bernie: Okay, so we'll start the video. So this is the very close up view of the intake manifold port. There's one port that flows continuously and one that gets blocked off with this actuator flap. And you'll notice in this area here, there's a lot of play in these plastic moving arms. So we'll just fire it up right now and you can see. You notice there's an incredible amount of movement. 

Mark: Wobbling around pretty good.

Bernie: Yeah. Wobbles around and if you look at these two different ports, you'll see that one of them's moving and the other one isn't even moving. So there's a lot slop in this piece here. You'll also notice there's a lot of gunk inside that ... all the passage ways and that's stuff that really needs to be clean out. I'll just play the video one more time, so you can have a good look at it. So this is why we're talking about the intake manifold. We're talking about these intake manifolds runners. They sometimes call them swirl valves, variable intake actuators. I can't think of all the names. Different manufacturers use different names but there's a motor that actually operates that the computer sends a signal, the motor moves the valves and that's what makes it go. 

Mark: And so that would affect the performance and economy of the vehicle? 

Bernie: Absolutely. It does make a difference. And with those blocked ports as well, it makes a difference. I'll just show you ... this is the new manifold. You can see the arms moving. You can see how clean this is too. You can imagine how much more air is actually flowing through the engine with it set up like this. I'll run it again. Again, there's no play in any of these rods. They're all moving exactly at the same speed, same time.

Mark: Very nice. Back to you.

Bernie:Makes a big difference with it all clean. 

Mark: So then do you end up obviously changing the manifolds just for an oil leak? 

Bernie: We did. Well, we did it while we were in there because the manifolds have to be removed to get at the oil leak, to access the oil cooler. So it kind of made sense to change to them while it's all out because there's no extra labor charge. I mean, the parts are expensive, no doubt. And it's kind of a shame to toss away what's a perfectly good manifold but that's the way they manufacture them, it doesn't leave any option to replace those rods or linkage pieces. You have to change the whole manifold. And one of them comes with the actuator motor and this is an item that also had some oil had soaked the motor and that's a failure item on these engines as well. So this has been a preventive maintenance for future issues. 

Mark: And was it just a gasket issue or what was actually leaking on the oil cooler?

Bernie: The oil cooler is seals leaks so it's where the oil cooler meets the engine block. There's two rubber seals and they harden up and leak after a while and they can just ... it was leaking horrific amount of oil after. And we diagnosed it, cleaned it. There was a lot of oil coming out after ten minutes of driving, this little small puddle forming on the ground. So there's a lot of oil that can leak out.

Mark: So does it need to be this complex?

Bernie: It does and just actually before we talk about the complexity, I was going to say on the manifolds, it's interesting 'cause 2008 is the last year that Mercedes made these where there isn't a switch on the end of those actuator rods. 2009 and newer they put a little micro-switch on the end of each rod so when the motor moves the linkage, it if doesn't move far enough it will actually cause your check engine light to come on instead of trouble code. So you're really at that point force to change the intake manifolds. On these older ones, you don't actually have to change them if it's broken as long as the motor moves, the computer thinks it's working. So they made it a little more complex in newer models so you can actually get away with not changing them but in the case, they're still an effect of the performance so it's best to do it. The question about the complexity, does it need to be this complex, I'd say, yes it does in this modern era. I mean at one time diesels were simple, reliable, mostly reliable. Some weren't as good as others. But you don't find like a lot of older German diesels, Volkswagens, Mercedes they're very reliable diesel engines. And lot of the older American trucks they just you know turn the key, they start. You didn't have to do a whole lot to them. But they stunk. And they put out some horrific pollutants into the air, a lot of smoke and the nice thing about these diesels is you don't see a lot smoke, they don't smell so bad even though they don't ... they're not as clean as advertised as well know but they do make you know, it does make a difference. So I'd say yes, unfortunately it does need to be this complicated if we want to have clean air, cleaner air, fuel economy and performance. 

Mark: So there you go. If you're looking for service on your ML320 or any Mercedes Benz diesel product in Vancouver, the guys to see are Pawlik Automotive. You can reach them at 604-327-7112 to book your appointment. You have to book ahead, they're busy or check out their website, pawlikautomotive.com. Lots and lots of information on there, hundreds of articles on all different types and models of problems and cars and trucks, or our YouTube channel Pawlik Auto Repair or our lovely new podcast. Thanks, Bernie.

Bernie: Thanks, Mark.

About the author 

Bernie Pawlik

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