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Loose Diesel High Pressure Injection Pump Damages Engine?
A diesel odor entered my 2009 GL320 Bluetec (X164), with a little over 150K. Upon inspection, I could see a wetness on part of the engine and was sure it was diesel. Flatbedded it to a repair shop and they provided the following diagnosis:
the high pressure injection pump was the source of the leak - a new pump would be needed;
the pump is bolted to the engine by 4 screws and only one screw was viable - the remaining 3 holes had stripped threads; and
the pump damaged the cylinder head beneath it.
Outside of the fuel pump leak and despite and cylinder head damage, the engine ran with no unusual vibrations or roughness. No changes in power or fuel consumption experienced. The repair shop recommend that I not replace the pump (approx $1k parts and labor) as they would not be able to properly secure it to the engine with just one bolt. Further, they said an improperly secured pump would continue to damage the cylinder head and the pump would fail again prematurely. They recommended that I sell/trade the GL as-is or do an engine replacement. I asked them to provide an estimate for replacing the engine. I wanted to understand the cost as there was nothing else wrong with the GL and it was still very comfortable/enjoyable/functional especially on road trips. They took several days to search and said the best option they found was an engine with 70K miles for approx $8500. Total cost to do the replacement would be around $12K. Did not see that coming. The shop recommended that I sell/trade it in. Outside of maintenance costs, I love my GL and intended to keep it until it died. Just thought I'd get more than 150K miles out it. I'd be fine with putting $5-6K into it if that meant it lasted another 2-3 years. $12K is more than I want to put in it.
So, I have a few questions I hope the group can help me with before making a final decision:
Is there anyway to fix the stripped bolt receptacles so that a pump could be properly secured?
Even though the engine seemed to run fine before I noticed the leak, does the damage to the cylinder head mean an engine replacement is the only solution? With a new pump, would the current engine make it another 2-3 years?
Is $8500 a typical/reasonable price for a used replacement engine for a 2009 GL Bluetec?
Any help/advice would be appreciated as I try to determine what to do. Thanks.
I think there are many steps you can take before making a final decision. Can you take a picture of the area you’re talking about because none of this makes any sense to me. What’s your relationship with this shop - long time trusted customer, or first time walk-in? That may have colored their response to your problem somewhat.
1. Absolutely, but depends on application. Helicoil is a brand of rethreading hardware that is used for spark plugs, so depending on your application it may work.
2. Pics to clairify how this pump fits on the head, or someone with detailed knowledge of the om642 to chime in on what kind of physical damage a loose pump can cause to the head. Erosion of metal? Cracked head?
3: Not only no, but hell no. $8500 is about what your car is worth on a good day. Why throw that kind of money at it - nothing wrong with the motor (yet), right?
Last edited by Max Blast; May 22, 2021 at 05:15 PM.
yes, depending on the damage to the engine there might be few solutions. I don't know where exactly is this fuel pump located on your engine but shop should suggest some options before jumping to engine replacement. As Max said, helicoil is a very good option especially in non-stress position where continues tension is not needed.
Another option would be to use a tap and die set to thread one size bigger threads, if space allows. Again, this option might be limited depending upon the location of pump on the engine.
Another possible route to explore would be using high temp adhesive or aluminum welding IDK.
Is it only attached to head? can head only be replaced?
Absolutely no need to spend more than what is this truck is worth. Buy another for the same price and keep it as parts or trade it in.
Good luck
The pump is right there on the front of the engine. Although I've never taken mine off, it looks about as straight forward as straight forward gets. Looking at my pump, it sure looks like there are 3 bolts to me... did I miss one?
I question a shop that can't figure out how to clean/chase or cut new threads or doesn't know what a helicoil is. I imagine the damage is to the mating surface between the pump and head or possibly where the neck of the pump fits into the head. We'd really have to see where the damage is and to what extent it is. If it's the mating surface, that is probably an easy fix. If it's the hole in the head, where the neck of the pump fits in, that seals with an o-ring - if the interior of that hole is buggered up, that could be more difficult... but not necessarily impossible (depending on the severity).
Max, c'mon, man I know you really have a thing against the diesel... but blaming a whole engine line for some bolts that loosened up when we know absolutely nothing about the history of? This has absolutely nothing to do with a gas vs diesel thing. It's simply a "bolt in a hole" thing. You're really stretching on this one! Besides, with a 150K on the clock, wouldn't it be expected that some things can loosen up? Part of "maintenance" is checking on these kinds of things - whether it's something someone does themself or hires someone to do. It's a used vehicle - things need to a looksie once in a while.
The pump is right there on the front of the engine. Although I've never taken mine off, it looks about as straight forward as straight forward gets. Looking at my pump, it sure looks like there are 3 bolts to me... did I miss one?
I question a shop that can't figure out how to clean/chase or cut new threads or doesn't know what a helicoil is. I imagine the damage is to the mating surface between the pump and head or possibly where the neck of the pump fits into the head. We'd really have to see where the damage is and to what extent it is. If it's the mating surface, that is probably an easy fix. If it's the hole in the head, where the neck of the pump fits in, that seals with an o-ring - if the interior of that hole is buggered up, that could be more difficult... but not necessarily impossible (depending on the severity).
Max, c'mon, man I know you really have a thing against the diesel... but blaming a whole engine line for some bolts that loosened up when we know absolutely nothing about the history of? This has absolutely nothing to do with a gas vs diesel thing. It's simply a "bolt in a hole" thing. You're really stretching on this one! Besides, with a 150K on the clock, wouldn't it be expected that some things can loosen up? Part of "maintenance" is checking on these kinds of things - whether it's something someone does themself or hires someone to do. It's a used vehicle - things need to a looksie once in a while.
You’re right to a certain degree - I do despise this motor and the cost cutting decisions or just plain bad engineering that went into it - but this seems a rather simple mechanical problem. I did look up a replacement pump and it looks like it has three mounting bolts and inserts into the head, possibly cam driven? I can’t with the information provided see that this is terminal for an otherwise functioning engine.
Either the OP is getting took or we don’t have an accurate problem statement. Hopefully we can see the actual, chime in and help OP.
It is cam driven, i've seen pumps fail and destroy cams/jump timing on the engine when they lock up. Probably why the bolts were shaking loose in this case, but without seeing it, I have no idea. Never seen one loosen up on it's own.
MaxBlast, tell me what information I need to provide and I will try. Please keep in mind that I am a "layperson" who does basic stuff. I changed my disc brakes last month; that's the kind of stuff I do. I have never worked on my engine or drivetrain. Nothing mysterious going on here. It started with smelling fuel and ended with being told it's not repairable. Shocking...at least to me. Now, I'm just trying to make heads or tails of my situation. I appreciate you and the group looking at this. Many thanks.
Seems like an obvious place to use helicoils if the flanges with the bolt holes are still intact. Supposed to be stronger than the original threads. I've never had one fail.
Seems like an obvious place to use helicoils if the flanges with the bolt holes are still intact. Supposed to be stronger than the original threads. I've never had one fail.
Agreed, properly done helicoils work perfectly and are stronger than original threads if the depth remains the same due to a larger diameter thread into the original material (more contact/surface area).
I would remove the pump and repair the thread before I worried about a replacement engine.
So what Dennis and ItalianJoe have posted - look at the video and remove your pump. See for yourself and document your shop’s concern with the fitment, and post some pics of the damage here.
It looks very straightforward and hopefully the damage will reveal itself to be repairable in situ.
Thanks all. I watched the YT video and that seemed straightforward. Will give it go and post back once I do. Do I have to worry about any fuel leakage while doing this?
BTW, I thought I sent a post with pics of the pump and engine (they were provided by the shop). I don't see the post (probably user error) and I'm assuming the group never saw them. My apologies for not providing visuals. I'm still going to remove the pump, but here are the pics taken by the shop. When I remove the pump, I should see the exact same things as in these pics.
Thanks all. I watched the YT video and that seemed straightforward. Will give it go and post back once I do. Do I have to worry about any fuel leakage while doing this?
Maybe a tiny bit - a rag or two will be all you need. But, the good thing about diesel is that it's not dangerous - it's not "highly" combustible like gasoline would be. I would just keep a rag around the nut as you loosen things in case it's still under some pressure.
BTW, I thought I sent a post with pics of the pump and engine (they were provided by the shop). I don't see the post (probably user error) and I'm assuming the group never saw them. My apologies for not providing visuals. I'm still going to remove the pump, but here are the pics taken by the shop. When I remove the pump, I should see the exact same things as in these pics.
it is hard to tell with these pictures provided but it appears the center hole is fine and all that’s needed here is to retread two bolt holes. If you can get a better vantage by cleaning it up a bit that would help, but I am not seeing any defensible reason for that shop to leap to the conclusion that you need a new engine to fix something as straightforward and common as this.
Last edited by Max Blast; May 29, 2021 at 09:17 AM.
I agree with Max. Again, without seeing it in person, it appears there's plenty of meat available to tap new threads. I'd go looking for more of a "mom-n-pop" local garage - they should be able to help you with this - especially if they've been around a long time and/or have mechanics that are on the "older" side
The more important thing to look at is that sealing surface that was mentioned above. That's the part that's going to keep it from leaking. I don't have enough experience in this area to say whether some special gasket maker type stuff (or something like JB Weld) would work to help seal things... IF the area is damaged - it may not be. I can tell you this, though... I would definitely give it shot before repalcing the head or the engine!!! Maybe a larger (thicker) o-ring would work? Also need to check out the gear-drive mating setup.
Last edited by DennisG01; May 29, 2021 at 10:08 AM.
Looks like the engine is toast. I'm guessing it was leaking or loose, someone overtightened, the bolts stripped, and the mating surface was destroyed by vibrations. Even if you could tap and run larger screws, I think it would still leak due to the mating surfaces being worn. Maybe you could use a crap load of sealant or JB weld and it would hold but I doubt it. First damage like this I've seen.
Looks like the engine is toast. I'm guessing it was leaking or loose, someone overtightened, the bolts stripped, and the mating surface was destroyed by vibrations. Even if you could tap and run larger screws, I think it would still leak due to the mating surfaces being worn. Maybe you could use a crap load of sealant or JB weld and it would hold but I doubt it. First damage like this I've seen.
I would not go to that conclusion just yet. Even if the mating surface is boogered up there are things you can try to seal it up - like I said way early on, jb weld that **** and leave it. It’ll probably last the remaining lifetime of this vehicle, which is a couple of years. And even then it’s only the one head that needs to come off, unless what we’re looking at here is that this pump has self-machined out an oval hole in the head and all that aluminum has been shot through the engine. But OP claims no symptoms other than a leak, so perhaps not.
Seems to me that the shop OP used went to the extreme solution without really proving out the stops in between.
but again, I’m not seeing anything that isn’t repairable by someone with decent mechanical skills.
Last edited by Max Blast; May 30, 2021 at 10:58 AM.
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I know you really have a thing against the diesel... but blaming a whole engine line for some bolts that loosened up when we know absolutely nothing about the history of? This has absolutely nothing to do with a gas vs diesel thing. It's simply a "bolt in a hole" thing. You're really stretching on this one! Besides, with a 150K on the clock, wouldn't it be expected that some things can loosen up? Part of "maintenance" is checking on these kinds of things - whether it's something someone does themself or hires someone to do. It's a used vehicle - things need to a looksie once in a while.
