November 5

2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor

Podcast2018, Jeep


Mark: Hi, it's Mark Bossert here with Mr. Bernie Pawlik of Pawlik Automotive in Vancouver. In today's podcast, we're talking about Jeeps. How you doing this morning, Bernie?

Bernie: Doing very well. 

Mark: So, we're talking about a 2008 Jeep Grand Cherokee, three-litre diesel, that had a swirl valve motor problem. What was going on with this Jeep?

Bernie: So, the owner of the vehicle brought the vehicle to us with a ... Their complaint was that there was a warning light on the dash. It looks like a lightning bolt, and at the same time that that happens, the vehicle loses power. So, it's basically a power loss indicator light. The check engine light was also on at the same time.

Mark: So, this vehicle has the famous Mercedes three-litre diesel. Is there something different about this power plant in a Jeep?

Bernie: Not really. There's only a few subtle differences, but I mean, essentially, the engine and how it operates is the same as a Mercedes three-litre. Most of the parts are interchangeable, but there's some emission items and some of the air intake ducting is slightly different on the Jeep, but most of it is the same as the Mercedes. Not exactly, but the guts of the motor are definitely the guts. When you take it down to the basic engine itself, it's pretty much exactly the same.

Mark: So, the swirl valve motor ... Can I say it right? I'm old, I can't say it right. The swirl valve motor, I would assume that was the cause of the problem?

Bernie: Well, it was part of the problem. The swirl valve motor, essentially what it does is it operates some valves in the intake manifold. The intake manifold has two runners in it to each cylinder, and one of them can be opened and closed ... The ports can be opened and closed with the swirl valve motor, and the reason for that is just to increase or decrease air flow and the rate of air flow into the cylinder, depending on different engine conditions and different engine speeds. So, the swirl valve motor will actually operate these valves, and what can happen is the valves also get carboned up, or the actual rods that are actuated are made of plastic, and they tend to wear over time, sometimes quite severely. We've seen them really badly worn on a lot of Mercedes and Jeep products over time.

Mark: What about other parts? Is there other parts that need to be replaced at the same time, typically?

Bernie: Well, yeah, so this job we started off with the swirl valve motor being the complaint and verified that was the issue, but we also noted, as soon as we started taking things apart, there was a lot of carbon deposits in the intake ports, and we ended up removing the intake manifolds, finding a severe amount of carbon deposits in the intake manifolds and cylinder head ports, which is not uncommon. It's about 230,000 kilometres on this engine. It's kind of a normal amount you'd find. Also, there was some oil leaks from this engine, and right underneath the intake manifold sits the engine oil cooler, which is a very common cause for oil leaks. There's some seals that hold the oil cooler down in the engine, very common. So, we replaced those while we had it out as well. 

Let's get into looking at a few pictures here of what we found when we removed the intake manifolds. Okay, so here's a view of the dash with all the warning lights on, just when you turn the key on initially, and that is the light of concern for the client, with the yellow arrow pointing to it. That looks like a lightning bolt, and that is basically a power loss indicator light, or that the vehicle's in limp mode because of a major issue. Also, you have the check engine light over here, which was on. The owner told us it had been on for a long time for a glowplug code. There was a code for the swirl valve motor, also an issue with the glowplugs, and we actually serviced and replaced those. 

2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor
2008 Jeep Grand Cherokee 3L Diesel-Swirl Valve Motor

Well, we did this, but that's a story for another podcast. So, there's our instrument panel. Let's get into looking at a couple other items here. We'll have a look at the swirl valve motor. So, that's the bottom side of the swirl valve motor. Again, it's kind of oily and grungy. That's kind of a common cause of issues with these motors. There's the top view of the motor, electrical connector. Carbon deposits, this is the ... It's a plastic piece that connects the two intake ports and connects it to the air duct from the turbo, or, I should say, from the inter cooler. The EGR port is here, and these are the intake manifolds. You can see just how much carbon is in here and just to really appreciate how much carbon is in there, this is what it looked like after we cleaned it, a profound difference. I mean, there was probably ... If you look at this view here, there's, I don't know, less than 50% airflow available through that particular area. 

Mark: Yeah, I was going to say, two-thirds blocked, basically.

Bernie: Yeah, exactly, precisely, and looking ... This is the cylinder head. Sorry, the intake ports in the cylinder head. You see there's a round one, this is where the swirl valve is located. In this one here, there's no valve, it has constant airflow. But again, you can see there's at least ... There's only 50% airflow available through this port as well, and a little more here, but it's still restricted. There's a view of the intake manifold, the old manifold. Again, you can see a lot of carbon on these pieces. So, this is actually the swirl valve here. Mercedes uses a different name for it. It's like a variable intake runner, but Jeep uses the word swirl valve.

These plastic rods here, there was some wear on these. It was warranted replacement, but we've seen these where they have some extremely bad wear, and on newer versions of this engine, like a Mercedes from 2009 and newer, they actually have a little switch at the end of this rod, so when the swirl valve motor moves the rod, it will actually cause a switch to send a signal to the computer that it's actually working, and when these get worn badly enough, it'll actually cause the trouble light to ... Check engine light to come on and set a trouble code for the intake runner not operating. So, when these get really badly worn, that'll happen, but on an '08 and older, and on Jeeps, that code is never an issue because they never monitored that particular thing. There's another closeup view. Again, you can see all the carbon deposits in the intake manifold, and there's a view of the valley of the engine, the oil cooler. That's the oil engine cooler. You can see the intake ports. We've cleaned them out. There's still some carbon in there, but generally, 99% of it's been removed. 

Mark: So, what causes all of this carbon buildup, and why is it so common on so many diesels?

Bernie: Carbon buildup? Two things. First of all, diesels, as you can see on ... Especially on not-modern diesels, there's a lot of soot, so there's a lot of particulate in diesel exhaust, and the reason you get the exhaust into the intake system is because of the EGR system, exhaust, gas recirculation. It helps lower the NOX emissions substantially. That's a big issue on diesels, so having a good EGR system is important. Plus, it also cools the combustion temperature, which actually eliminates NOX. Yeah, I mean, it really is ... Stepping around things here, really, it's all about emissions. So, that's why, and they're pretty sophisticated systems on more modern diesels because the emission requirements are so stringent. That's why we get so much carbon deposit.

Mark: And NOX is nitrous oxide, is that right?

Bernie: Oxides of nitrogen, yeah. The air has oxygen and nitrogen, and nitrogen's inert gas ... It doesn't do anything with combustion, but it does combine with oxygen and creates some hideous pollutants.

Mark: It forms a particle, or there's particles that are just part created from the combustion process, is that ...

Bernie: Particles from diesel are actually not NOX, they're actually ... It's actually just particulate. I believe it's just soot from the combustion process. Yeah. I did have someone explain how soot and all those details work, but I'm not quite ... But it's part of the combustion process, but it's not NOX. It's kind of a smog-producing chemical, among other things, and obviously not good to breathe, either. 

Mark: Yeah, it would kill you.

Bernie: Yeah. 

Mark: So, what happens when the carbon deposits get really severe?

Bernie: Basically, your vehicle won't go anywhere. In the past, I mean, this has been an issue with TDI, Volkswagens for many years way, many generations back. We serviced a lot of them where the intake ports would plug up so badly, by the time you take the intake manifold off, you'd be lucky to fit a quarter inch drill bit into the intake. There would be about that much breathing space in the port. They would be insignificant. So, there would basically be no airflow going into the engine, so you'd be going up a hill and the engine just couldn't suck the air into produce the power. Yeah, so that's basically what happens. Eventually, you just lose performance. I would say the Jeep, once done, will perform substantially better, even though it was probably reasonably good to begin with.

Mark: The whole idea of the swirl valve motor or having that secondary intake is when the engine needs ... You step on the gas or the fuel and are requiring more power, more speed captain, that opens and allows more air in to give you more power, basically, along with more fuel. 

Bernie: Exactly, but I think a lot of the reason they use variable intake runners ... And they do it on gas lean engines as well, is it creates a certain ... They call it a swirl valve, because as the air's sucked into the engine, or, well, in this case, being a turbo charger, it's actually forced in, it creates a swirling motion. So, as it does, it improves the combustion process. As the air swirls in, the combustion is better, so it's more efficient, there's more power, there's better fuel economy, there's lower exhaust emissions. I mean, if you can burn the fuel 100%, the emissions are lower. Plus, of course, better economy and more power. So, depending on what speed the engine's running, if it's idling, it needs a certain amount of movement and flow, if you've got full throttle, it's a different situation.

Mark: Right. So, carbon deposits would obviously be a big problem in making that efficiently run properly, so is there a way to prevent these carbon deposits?

Bernie: Well, I have a couple of things to say, but I mean, first of all, I mean, the best way to prevent them with a diesel is to be running your diesel. Ideally, a diesel needs to be run hot, it needs to keep running all the time, and the people who will suffer the least amount of carbon deposits owning a diesel will be people who start their car up and they drive out on the highway for an hour and back, or they drive across the country. They do a lot of long drives with the engine cooking hot all the time. Like most us, you start your car up, you drive your kids to school, you drive home, or you drive to work short distances, that's when the carbon deposits start building up. So, usage is one thing, but of course, it would be kind of stupid to just go drive your vehicle out on the highway for a couple hours just to get to work. 

So, you just got to work with what you've got, and this is why I've often said you should really look at ... Do you really need a diesel? I mean, the fuel economy is extremely attractive, but as the engines gum up over time, and it happens to all of them if you don't use it hot, you will pay a lot of money for maintenance to have these kind of things cleaned out and repaired and replaced. I mean, the other thought I've often had is why don't the manufacturers put a filter in the EGR system that even if you had to throw it away every 5,000 kilometres, it would just save so much of this kind of headache. So, never heard of one available. It's an interesting concept. Not sure how you'd ever put it in. Every 5,000 kilometres would be kind of an irritating thing to do because it would plug up pretty fast, but it just seems to me like that would have been a good idea to consider when building a lot of these diesels.

Mark: It just becomes part of your oil change, is that particulate filter gets changed too.

Bernie: Well, exactly. To me, it would just be a huge savings in terms of ... Yeah, in terms of maintenance, and extremely costly maintenance. 

Mark: So, Jeep Grand Cherokees. How are they for overall reliability?

Bernie: I'm going to say fair. They're not the most reliable vehicles. I mean, we're talking about a pretty major repair on this one here. These diesels do have some issues, and there's front end work that ... Suspension, steering work that needs to be done on Jeeps, perhaps a little more frequently than some other vehicles. Gasoline motors are pretty reliable. I mean, these diesels are too, but there are just expensive jobs that need to be done every once in a while. 

Mark: And a great off-road vehicle overall and comfortable to drive in.

Bernie: Oh, they are. They're awesome. I mean, people love their Jeeps, but just as I often say, people love certain kinds of vehicles, and you will spend more money owning a Jeep than you will on a lot of other cars. 

Mark: So, if the benefits are there for you for off-road use or you like the Jeep, it's a good vehicle?

 Bernie: Absolutely. 

Mark: So, there you go. If you're looking for service for your Jeep in Vancouver, the guys to see are Pawlik Automotive. You can reach them at 604-327-7112 to book your appointment. You got to book ahead, they're busy. Remember, these guys are 19-time winners of Best Auto Repair in Vancouver as voted by their customers. 19 times. This is a good shop, so you've got to call and book ahead. They're busy. Or, you can check out their website, You have hundreds of videos on YouTube, almost eight years worth of videos on there, and especially thank you for watching, listening to the podcast. Thanks, Bernie. 

Bernie: Thanks, Mark, and thanks for watching and listening. We really appreciate it. 

About the author 

Bernie Pawlik

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