August 2

2003 Chevy Silverado, Diesel Fuel Injector Replacement

Auto Repair, Chevy Trucks GM Trucks


Mark: Hi, it’s Mark at Top Local Lead Generation; we’re with Bernie Pawlik of Pawlik Automotive in Vancouver; talking about Chevy diesels. How’re you doing Bernie?

Bernie: I’m doing well Mark.

Mark: So something we really haven’t covered before I don’t think even ever, is a any kind of Chevy diesel stuff, so we’re talking about a 2003 Chevy Silverado and the fuel injector replacement, what was going on with this one?

Bernie: So this vehicle was suffering from an interesting issue, uh running pretty well but what was happening is that there is over a period of time the crankcase was filling up with diesel fuel, there’s an internal fuel leak inside the engine and so over you know, a period of say an oil change, I would add two or three extra liters of diesel fuel to the crankcase which is not a good thing you really want to be lubricating your engine with motor oil not diesel fuel.

Mark: Yeah, even tho they run on oil that’s not the right oil to lubricate it.

Bernie: No, I mean it’s better than running gasoline but at least it’s not exactly proper.

Mark: So is an internal fuel leak common on diesels?

Bernie: Well it is on some, it’s this 6.6 liter GM diesel which is actually made by Isuzu, awesome engine, very reliable, all the fuel injection plumbing is pretty much inside the engine. I’ll show you a few pictures in a minute but the injectors are inside the valve cover, all the fuel lines, I mean there are external fuel lines but all the return lines are inside the valve cover, the fuel pump, the high pressure pump bolts into the front of the engine, it can leak into the engine as well, um you know it’s common on a lot of engines, the 6 point, we’ve seen a lot of 6.4 liter Ford diesels have that issue but most, many diesels have the injection plumbing inside the engine so it can happen on any, even Ford we’ve seen quite a few where the, there’s actually a high warning light will come on or the check engine light will come on if the oil level actually gets too high so it’s a sensor to actually deal with that on the Ford.

Mark: So how’s the injector replacement on these trucks?

Bernie: It’s a huge job, it’s an enormous jobs with about 12 hours’ worth of work, can be even more sometimes but it’s a lot of work and I’ll just share a couple of photos here just to kind of give you an idea of what, what we have here, um so this is the, I’ll just expand the picture a bit, we still there?

Mark: Yeah

Bernie: O.K. so this is what, this is the top of the engine looking at the valve cover, there’s a lot of wiring and accessories and pieces that we remove. This is looking at the right cylinder bank and I’ve just gotten sort of front three cylinders you can see the back one is out of the picture because there’s piping in the way and not making such a good photo but the, this is basically what you’re looking at before you take the valve cover off so those three pipes that are bent into interesting shapes are all the high pressure fuel pipes that come to the fuel rail and go into the fuel injector. Now in our next photo we’ll have a look with the valve cover removed and this is the valve cover off and also there’s a, there’s a metal plate, spacer plate that goes between the valve cover and the and the cylinder head and that, that’s been removed as well so you can see a little more. We’ve also removed the wiring harness from the fuel injectors so this gives us a clean view of the injectors and the return lines and where some of the possible leaks can occur. All the red arrows point to the fuel injectors, the blue arrow points to the return pipe so this is sort of excess fuel that the fuel injectors don’t need and that returns the fuel back into the fuel tank through of course a lot of plumbing and the green arrow points to a couple of possible leaks. Now there’s I didn’t put green arrows everywhere where it could possible leak but there are seals, banjo bolts and seals in all, in these particular areas plus it goes to each injector so there’s, there’s more points but there’s you know, there could be any sort, if there’s any fuel leak in any of these pipes just goes directly to the crankcase and fills the oil and the injectors themselves can leak also so these are some of the places fuel can leak. This is what’s on the inside again, it takes many, many, many hours of removing pieces just to get to this particular view so it’s a large job.

Mark: So once it’s all done, what’s our final outcome here?

Bernie: Aw, the engine runs great now, I should, I didn’t talk about the diagnostic process we went through to this because it’s, it’s a little tricky to find you know, a fuel leak inside an engine when you can’t actually run the engine uh, by the time you remove everything you can’t run the engine to find the leak so we have to look at you know, mileage on the vehicle, what are the possibilities and so prior to doing any removal we get some diagnostic tests with a scan tool and you can look at the fuel rate and what the you know, how much fuel the injectors are actually injecting and see you know, what sort of compensation is being made either worn or leaking injectors and we found that several of the injectors of the fuel delivery rate is much higher than expected but this vehicle had 330,000 kilometers, talked to the owner, he’s owned it since 80,000 k’s and said never replaced the injectors so he’s got very good life out of these injectors and, and really the most common cause of the problems is bad injectors so or injector so we replaced the injectors, it’s not a 100 percent guarantee that this is going to solve all the problems but I would say first of all the engine’s going to start firing and running properly using an even amount of fuel. The only other real possibility because we’ve changed all the seals on the return pipes is the high pressure injection pump which is located on the front of the engine and with this kind of mileage it’s possible that that pump could be leaking as well but short of doing this repair first it’s really impossible to tell which you know, where it’s leaking, it’s always, it’s one thing about diesels is it’s really complicated often to diagnose things and you’ve got to by experience and knowledge, common problems first and then go from there.

Mark: So you said a word that I don’t think we’ve talked about a lot, like these are under a lot of high pressure, like how high is the pressure inside?

Bernie: You know some of these like 25,000 psi, this is just an insane amount of pressure in the system so there’s a, there’s an amazing amount of pressure and fuel injectors in these modern vehicles and that goes for modern gasoline engines too, they’re extremely high-tech you’re dealing with enormous pressures, you know, extremely precise fuel delivery I mean, I don’t have the measurement terms to say in this you know, found out but these, the amount of fuel delivery is so minute and a lot of these injectors on diesels, now this is an old 3, it’s kind of old but like a lot of newer diesels you can barely hear the engine running because it’s because the injection, some will do actually up to 7 injection pulses per combustion strokes so they’ll fire a couple little shots of fuel as the pistons coming up, they’ll fire the main shot then they’ll fire a couple more and that’s what keeps the engine from actually making the loud knocking noise that you hear on diesels typically, it’s just pretty, pretty incredible but things do go wrong, this is why you need to change your fuel filter. Now this is another interesting point, I talked to the owner, he goes you know don’t worry about changing my fuel filters, I just changed it last week because I change it religiously every six months so this is an owner that’s really conscientious about taking care of their vehicle, you know every six months is probably too much but you know what, he’s got three hundred thirty thousand kilometers on a set of fuel injectors, there’s most diesels never go that far so you know, good maintenance does pay off.

Mark: Absolutely, that’s the message of all these really isn’t it?

Bernie: It is.

Mark: Maintain your vehicle and it’ll treat you a lot better than not maintained.

Bernie: Yeah, you know we’ve had a couple Mercedes that you and I have talked about over the last six months, 3 litre Mercedes diesels where people have not changed their oil, one of them cost you know $22,000 for a new engine, another one a couple weeks ago, the turbocharger basically broke in half and these are under 50,000 kilometers and like Mercedes 3 liter diesel taken care of it, it will last you three, four, five, should last 500,000 kilometers, you know just change the oil regularly, yeah there’s a few things that will go wrong, you’ll spend some money but overall you know it will last a long, long time .

Mark: So back to this Chevy and how are Chevy GM diesels comparing to the other American diesel trucks?

Bernie: I think they’re really good, you know personally, you know to me it’s between this engine or Cummins if you’re looking at these older generation diesel and actually into the newer years and I guess the Ford 6.7 we haven’t run into any problems with that yet and I haven’t heard of any problems, Ford may have finally figured things out but I mean they had two generations of really bad engines, just very, very costly and a lot of dissatisfied owners so I would not, they’re nice trucks I just wouldn’t touch a Ford diesel, you know it’s either and I think the Chevy’s are more reliable in terms of the actual truck, less front end parts as I was alluding to in an earlier hangout, we talked about Jeeps and you know, GM or sorry Dodge front ends wearing out I mean, by the time you hit 100,000 kilometers on a Dodge you’re doing all the ball joints and tie rod ends, they’re just, they all wear out so Chevy seems to be a lot more reliable, I mean overall I think that’s the truck I’d go for.

Mark: So, any final thoughts on this whole repair service.

Bernie: You know what, it’s only you know, due good maintenance, if you’re buying a diesel do your homework and I mean the other thing about diesel I’ve mentioned quite a few times is if you’re thinking about buying a diesel ever ask yourself do you really need one because they do cost a lot of money to fix, I mean this is not going to be a cheap repair bill for the customer but if you need a diesel to haul a lot of weight well then it’s worth it but if you’re just buying it just for show, I don’t know maybe a sports car might be a bit cheaper and more fun or get a truck with a gas motor, you know an F150 or you know, a half ton truck is, it’ll be more reliable and cheaper.

Mark: So, if you want some real honest truth about your vehicles and how to maintain them properly or you have a Chevy diesel and it’s getting up there and you need to get the injectors changed, the guys to call are Pawlik Automotive in Vancouver 604-327-7112, they’ve done a lot of this kind of work, they’re experts there someone you can trust, check out the website Thanks Bernie.

Bernie: Thanks Mark. Talk to you again soon.

About the author 

Bernie Pawlik

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