July 2

2017 Mercedes C300 Oil Pump



Mark: Hi, it's Mark Bossert. I'm here with Bernie Pawlik, Pawlik Automotive in Vancouver. Vancouver's best auto service experience. 24 times, 25 times winners of best auto repair in Vancouver. So many I can't keep count. Voted by their customers as the best. And we're talking cars. How are you doing Bernie? 

Bernie: Doing very well.

Mark: So today's victim is a 2017 Mercedes, a Merc. What was going on with this vehicle? 

Bernie: Yeah. So this vehicle came to our shop, no engine performance issues, but check engine light on and the owner was concerned about it. 

Mark: What's the process from there? What do you do? 

Bernie: Road test the vehicle, verify the concerns, in this case the check engine light was on, and the next step is to hook up a diagnostic scan tool and see what trouble codes are stored in the engine computer.

We usually scan the whole vehicle because you know, it's all part of the process. Scan the vehicle, found two trouble codes stored. One was for a PCV system, that's a crankcase breather system, and the other is for an oil pump control valve issue. 

Mark: Oil pump control valve. So where's the oil pump located in this vehicle?

Bernie: It sits in the oil pan, pretty much where you'd find it on almost any vehicle. Now as I mentioned, there's two codes, one of them, the PCV valve, once we've retrieved codes, we did a little research, okay, what does that code mean?

And we do a check for vehicle recalls, and we found there's actually a recall for the PCV code that had not been carried out. So we referred the owner to go to Mercedes and get them to take care of that because there won't be any charge for that. But the oil control valve, you know, there was a charge for that, obviously, because it wasn't covered by any recalls or warranties.

Mark: So this vehicle is a 2017. It's out of warranty at this point. 

Bernie: Yeah, it's a seven year old vehicle now. The warranty on the engine was probably five years, something around that range. That's kind of standard for most vehicles. Depends on mileage too. This thing was close to 200 K's, I believe.

Mark: So is there any other diagnosis that you can do to determine what's going on with that oil pump? 

Bernie: Yeah, well of course the code is for an oil pump control valve, but it doesn't necessarily tell us the valve's bad. There are tests and procedures we do because it can be anything. It could be the computer that's bad, it could be wires that go from the computer down to the oil pump control valve. Could be the valve, could be a wiring problem. We have a lot of access to repair information and data. You know, cars are so complicated. There's no way we can know it all. 

Almost every job we come across is a new thing. So doing our research and testing, we did some extensive testing on the wiring and found that basically that the circuit was open to the valve, which means basically the valve was either faulty or there was a broken wire. But it's a common issue. These valves fail. And also there's a wiring harness upgrade as well that goes inside the oil pan to the exterior of the engine. 

Mark: : All right. Let's go to some pictures. There's our 2017 Mercedes. 

2017 Mercedes C300 Oil Pump

Bernie: This is a four cylinder by the way. And so it's interesting, it's a turbo four cylinder, which is a way a lot of cars have gone. I mean, the C300 would have been a V6, you know, a generation back. But now they've of course gone for smaller, more compact, fuel efficient vehicles, but you know, lots of power with the turbo. So you're getting kind of the same power, more fuel economy, lower emissions.

Mark: Underneath. What do we have here? 

Bernie: So you're probably going to ask me, was this an involved job seeing as it's in the oil pan? And the answer is absolutely. It's a very, very labour intensive job. And this car is an all wheel drive. So that makes it even more complex because a lot of these all wheel drive cars, the axle shafts that drive the front wheels go right through the oil pan.

2017 Mercedes C300 Oil Pump

So that adds an extra level of complication when you have to pull the oil pan out. So we got a couple of different coloured arrows here. So this is basically a view of the bottom of the vehicle looking up. That green arrow, lime green arrow that points to the transmission. And the red arrow is the oil pan, which is the item that we needed to remove to do the repair.

The blue arrow is the transfer case for the all wheel drive system. Sorry, that's the front differential. And the yellow arrow points to the steering rack, power steering rack. So, and there's a subframe assembly which sort of surrounds all of that. You can see a black bar kind of near the red and green arrows.

Yeah, you're moving the mouse pointer. That's a sway bar. There's a number of things that have to be removed. Just to get to the oil pan, there's a lot of things that have to come out, including the drive axles. So it's a lot of work just to get to what we need to work on.

Mark: Drive axles. We can sort of see a knuckle here. Yeah. You can see a knuckle there. Yeah. Yeah. And this, so to orient it, this is the roughly the radiator here. 

Bernie: It's exactly the radiator. Yeah. You're looking at the front of the vehicle there. Yeah. That's the radiator. So this is like underneath looking up. And there's normally a plastic cover that covers over that. So if you were to hoist the vehicle, you wouldn't even see that, you have to remove the cover first. So there's a lot of removal to get to the heart of things. 

So here's the bottom of the engine with the oil pan removed and that red arrow is pointing at our oil control valve solenoid. We replaced that piece. You can see some black wiring that attaches just to the right of that. That wiring harness was replaced as well. That is a known problem for this issue too. This oil pump's chain driven. And you might ask, well, why is there a solenoid valve in an oil pump?

2017 Mercedes C300 Oil Pump

 It used to be oil pumps were just a gear that was driven, but now, you know, in order to get maximum fuel efficiency, the solenoid valve will control the amount of oil pressure that the pump's putting out. So sometimes you don't need a lot of oil pressure. So, you know, to develop high amount of oil pressure that takes energy. Robs the vehicle of power.

So, if you can put the right amount of oil pressure that's needed, then you have a more efficient engine. But the price of efficiency is things break down that never used to be on an engine before. And sometimes they're expensive to fix. 

Mark: Especially if they're buried in amongst many other things like this vehicle.

Bernie: Yes, exactly. 

Okay. So here's a view of our solenoid valve that we replaced along with the wiring harness connected to it. And we actually broke the wiring harness apart to take it out and fix it. But the customer can be assured that the new one in there is absolutely intact. But that's basically the solenoid valve there that was the culprit. And not a very expensive part either. Pretty cheap. But the bulk of this job, like the 95 percent of the cost of this job is all labour and service. Labour to get to the part and replace it. 

2017 Mercedes C300 Oil Pump

So this is the oil pan. We have a nice jet wash that we clean everything up in. So this looks like pretty near brand new. But if you see that sort of bar that runs across the middle. That's where one of the axle shafts resides. It goes right through that tube in the middle of the oil pan. So it's very complicated design. I mean, beautiful piece of aluminum casting for sure. Very precise.

2017 Mercedes C300 Oil Pump

Mark: So once everything's replaced on this vehicle, how did it run? 

Bernie: It was good. Yep. No check engine light. It's all good. Of course, the light will likely come back on. We cleared it, but the light will likely come back on because of the other code that the owner will take to Mercedes to get fixed for the recall. But other than that, it's all good.

Mark: So I'm noticing a pattern and we've done over a thousand of these videos. As cars get newer, they're getting more complicated and the weird little things that go wrong. That would normally have been like a PCV valve was pretty easy on my 67 Ford pickup. Yup. Reach in there, pull it out, no it doesn't knock, get the new one, slap it in there, boom, done. Took five minutes. Maybe. Now, it's a whole different situation. Is that what you're seeing as well? 

Bernie: Oh yeah. Everything's way more complicated. Way more complex and I'm not sure why things have gone from that little simple shaky PCV valve you're talking about to the complexity we see on so many. Like any car, they're complex. I wouldn't single out European cars. They seem to got complex earlier, but earlier than North American cars. I'm not sure why, but there's just something that probably allows for more precise control of the crankcase gases and things. We're kind of drifting off.

But you know, what's great about electronics is we've been able to control so many components that weren't controllable before which has added, it's actually simple to manufacture, but it's added complexity to the whole thing. But this is why we have modern cars with, you know, 300 horsepower out of a four cylinder engine. Whereas before you would need a high performance V8 to get that kind of power. So this is just kind of normal nowadays, you know, 250 horsepower, four cylinder. It's, it's average. 

Mark: Average.

Bernie: Yeah. And great fuel economy and low emissions.

Mark: So I guess the point I was trying to go towards was then this vehicle with the oil pump not working properly was in danger of causing even more catastrophic damage because everything is so complicated and the tolerances are so tight and so complicated in how the engine operates.

Bernie: Absolutely. Now, the thing is, you know, when some of these things fail is what's the default mode when it fails? And I would say the default mode is probably like, hopefully I don't know for sure, hopefully it's that you get full oil pressure as opposed to like, all of a sudden you've got a restriction because that would create an engine failure pretty quickly.

But the important thing out of this is, you know, when you have your check engine light on, have it looked at, inspected, you know, repair the work, don't just leave it. You go, Oh, it seems to be running fine. Have someone look at it. Sometimes you can leave your check engine light on.

I mean, I don't recommend it, but sometimes, you know, if your budget's tight or something, you know, some things on it with a check engine light are more urgent than others. If it's an internal engine issue, it's urgent. It's important. 

Mark: So there you go. You need some service for your Mercedes or complicated vehicle, modern vehicle in Vancouver, BC, Canada. The guys to see or Pawlik Automotive, you can reach them by phone at (604) 327-7112 to book your appointment. Or you can do it online at pawlikautomotive.com. You have to book ahead. They're always busy. Pawlik Automotive in Vancouver, BC Thanks so much for watching and listening. Thanks, Bernie. 

Bernie: Thank you, Mark. Thanks for watching.

About the author 

Bernie Pawlik

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