HPFP lifter failed, engine replacement really necessary?
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613codyrex
- Posts: 6
- Joined: Sat Jan 08, 2022 6:30 pm
- Car: 2011 Infiniti M56 S
HPFP lifter failed, engine replacement really necessary?
High pressure fuel pump lifter bucket failed (large hole in the bottom of the bucket) on my 2011 m56s, and a nissan dealer said that the entire engine had to be replaced since metal from the bucket would damage the engine which would make sense. However, after looking at videos and diagrams of the engine, it seems like the cam lobe for the HPFP and the HPFP are above/inside the timing chain "chamber" and i am not seeing how metal from the lifter bucket could make its way into the engine, rather it seems like it would fall to the bottom of the timing chamber and at most i would have to have the cam lobe replaced, HPFP and the timing chain if it had been damaged, of course i really don't know. This is one of the videos i looked at: https://www.youtube.com/watch?v=q44TEn4ioZo&t=256s, where you can see the Cam lobe for the HPFP on the right side of the engine inside the timing chamber, and in the very last picture of this infiniti service bulletin for a different issue (https://static.nhtsa.gov/odi/tsbs/2013/ ... 7-2549.pdf) you can see the lobe on the left side of the pic and it seems like it wouldn't be possible for the metal to go inside of the engine. Any help is greatly appreciated, thanks in advance!
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VStar650CL
- Technical Expert
- Posts: 11930
- Joined: Thu Nov 12, 2020 1:25 pm
- Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S
Re: HPFP lifter failed, engine replacement really necessary?
Cut open the oil filter. If it's full of metal, especially chunky stuff, then the debris migrated through the oil system and it's going to be everywhere. If you don't find much then chances are the engine is salvageable, but drop the pan to make sure. If you do repair it, the oil galleries and passages will need to be blown out very thoroughly.
Re: HPFP lifter failed, engine replacement really necessary?
Engine replacement might not be necessary, but that greatly depends on the degree of damage (how much damage, and over what period of time).
Unfortunately this is something that can only be determined by a proper teardown. Ideally, by the time your car stalls and you find the bucket to be blown out, it means that this has been going on for a while, and pieces of metal might have been circulating in the engine.
How does something leave the timing cover area and make it into the general lubrication system?
The same way the oil that is used to lubricate everything in that compartment does. There are passageways to allow fresh oil into the timing case, and spent oil out to go and get filtered.
So yes, if you are looking for large chunks of metal, they might be sitting at the bottom of the timing cover (ultimately, everything ends up in the oil pan), but if anything was suspended in the oil, it has probably travelled a few thousand miles within that engine.
Remember, this issue starts as friction wear, which means small pieces of the bucket are introduced to the lubrication system. As the wear increases, the degree of damage becomes exponential and might eventually take off a few large chunks. Large chunks don't really scare me since they rarely make it past the strainer in the oil pickup tube. It's the other stuff that has been circulating for months that concerns me, because that is the stuff that is sent to your solenoids and bearings - rod bearings, main bearings, camshaft and VVEL tray etc.
So what can you do?
The most basic resolution is to replace the bucket and keep driving.
- it's cheap and carries no extra risk beyond what has already happened, so you could try it.
- historically, this does not seem to last, as the new bucket usually develops a hole soon after installation.
The reason for the new buckets failing is that the same friction that eats away at the bucket usually damages the surface of the cam lobe.
- this might or might not be visible to the naked eye.
- maybe a better move would be to replace the HPFP driver as well?
That, unfortunately has no guarantee either, because you don't really know what your other bearings and bearing surfaces look like.
- you might have another 1,000 miles or 10,000 miles before the engine starts knocking.
- it's a matter of weighing your risks versus sinking more costs into it.
Dealerships aren't in the business of tearing down engines to answer the deep questions, so I understand why they would recommend replacing the engine. It's easier to insure or warranty your involvement if the history isn't already sketchy.
Unfortunately this is something that can only be determined by a proper teardown. Ideally, by the time your car stalls and you find the bucket to be blown out, it means that this has been going on for a while, and pieces of metal might have been circulating in the engine.
How does something leave the timing cover area and make it into the general lubrication system?
The same way the oil that is used to lubricate everything in that compartment does. There are passageways to allow fresh oil into the timing case, and spent oil out to go and get filtered.
So yes, if you are looking for large chunks of metal, they might be sitting at the bottom of the timing cover (ultimately, everything ends up in the oil pan), but if anything was suspended in the oil, it has probably travelled a few thousand miles within that engine.
Remember, this issue starts as friction wear, which means small pieces of the bucket are introduced to the lubrication system. As the wear increases, the degree of damage becomes exponential and might eventually take off a few large chunks. Large chunks don't really scare me since they rarely make it past the strainer in the oil pickup tube. It's the other stuff that has been circulating for months that concerns me, because that is the stuff that is sent to your solenoids and bearings - rod bearings, main bearings, camshaft and VVEL tray etc.
So what can you do?
The most basic resolution is to replace the bucket and keep driving.
- it's cheap and carries no extra risk beyond what has already happened, so you could try it.
- historically, this does not seem to last, as the new bucket usually develops a hole soon after installation.
The reason for the new buckets failing is that the same friction that eats away at the bucket usually damages the surface of the cam lobe.
- this might or might not be visible to the naked eye.
- maybe a better move would be to replace the HPFP driver as well?
That, unfortunately has no guarantee either, because you don't really know what your other bearings and bearing surfaces look like.
- you might have another 1,000 miles or 10,000 miles before the engine starts knocking.
- it's a matter of weighing your risks versus sinking more costs into it.
Dealerships aren't in the business of tearing down engines to answer the deep questions, so I understand why they would recommend replacing the engine. It's easier to insure or warranty your involvement if the history isn't already sketchy.