HPOP a warning (Fuel pump bolts)

lindenengineering

Well-known member
The HPOP that triangular looking casting hanging off the front of the driver's side cylinder head!
HPOP in fact a term used in the trade for the high pressure pump feeding the fuel system .

Its held onto the head by three (3) 7x1mm bolts that are sticky!
So to be used only once! Unless you daub them in blue loctite as a "get me by!!
Failure to check on this pump's security can, and in some situations will cause detachment and camshaft drive gear damage which drives the HPOP pump itself.
Seen two this week!!

This is a royal wallet flush repair so check yours every so often.
Dennis
 

220629

Well-known member
The HPOP that triangular looking casting hanging off the front of the driver's side cylinder head!
HPOP in fact a term used in the trade for the high pressure pump feeding the fuel system .

....
Dennis
Dennis,
Thanks as always for the information. :thumbup:

Does this apply to both the V6 and I4? Any particular model years seem prone?

:cheers: vic
 

lindenengineering

Well-known member
All on CD14 engines in older 906 Sprinters and a Jeep.

The Sprinter pumps simply came loose and shed their bolts, breaking some off in the head.
The latest I/we fixed yesterday was a simple drill out busted bolts and refit with new bolts.
At 289,000 miles no explanation and the other was at 127,000 miles. Just fell off!
If there was a common denominator then both engine produced a distinct cold start rattle as the timing chain took up.
The other one was simple DIY error.
The Jeep owner had DIY'd the pump, but had simply installed the original bolts--It too fell of taking the cam gear teeth with it!
That was not a cheap job !
Consequently a new shop policy!!
All pump disturbances MUST have new bolts installed.
Dealer didn't have them in stock but I did buy 30 off for future stocking arriving 24 hours later.
Dennis
 

Joshuaam

New member
Hello Dennis!

I had this exact issue happen to the engine you swapped out for me back in July of 2017... The Bolts fell out, in May last year with only 5k on the engine, we spoke a bit about this issue and unfortunately, you weren't able to cover it.

The pump fell almost all the way off, and in the process tooth a few teeth off of the gear attached to the cam that drives the pump. Do I need to worry about metal in the cylinders, or bearings? So far an engine oil check didn't detect any metal particulates.

Might you be able to let me know what this would entail, cost, labor etc? Can I just swap out the Gear at the end of the cam and swap the pump out, with proper bolts, and do an engine flush? Or am I looking at an entire rebuild on this engine?

Thanks.

Joshua
 
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SD26

2012 NCV3 3500
All pump disturbances MUST have new bolts installed.
Dealer didn't have them in stock but I did buy 30 off for future stocking arriving 24 hours later.
Dennis
Dennis, what's the torque spec on those bolts? Should one consider replacement at a certain mileage? 200k?
 

nutty

New member
"check yours every so often", should I just try to torque them to 18 NM and if they turn replace them (torque them down with blue loctite as a patch until I get my hands on a set of new)?
 
Is it possible for anyone to post a photo of the pump & 3 bolts so we know what we're looking for? Does anyone have an opinion whether this is an issue on a 2018 engine? Thanks!
 

lindenengineering

Well-known member
Its not an issue!
This Bosch HPOP pump is used on numerous applications with the same 3 fixing bolt patterns , its not unique to MB !~
The issue is that people think its a 6mm bolt, and./or an American factional size bolt and do not realize its one time use sticky 7mm x 1 bolt ONLY available from MB for MB applications.

I posted the info to draw attention of this fact for the DIY'rs and the YouTube Grads to this forum.
Dennis
 

Andrew_T

Active member
Quick question for @lindenengineering .
Denis, looking at my pump which is the original from 2008 based on the sticker on it , it doesn’t have the torx bolts I’m used to seeing all over the engine.
Im seeing 3 internal hex bolts holding the pump to the block.
Are these original you think or someone might have replaced them ?
I can post a picture of them later today if that helps .
 
Maybe someday someone will post a photo showing what is being described here, so we can all avoid the related problems. Until then, some of us will simply wonder about which 3 bolts we're looking for.... Appreciate the heads up! Just looking for clarification, since 4/20/19....
 

ptheland

2013 144" low top Passgr
Maybe someday someone will post a photo showing what is being described here, so we can all avoid the related problems. Until then, some of us will simply wonder about which 3 bolts we're looking for.... Appreciate the heads up! Just looking for clarification, since 4/20/19....
Here you go. As Dennis said at the top of the thread, it's on the front of the US driver's side (I'll call it the port side) cylinder head.

The first photo is for general orientation. In the second, I moved in closer and am pointing at it. Mine happens to be cleaner and a bit shiny because I had to have mine replaced recently to pass a CA smog check. The three bolts (they look to be torx, but didn't check carefully) are easily visible once you've identified the correct part.
 

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Kajtek1

2015 3500 X long limo RV
Side note - I have feeling that HPOP come from older Powerstroke engines, who had High Pressure OIL Pump, who was giving high pressure motor oil to the injectors and it was oil who compressed fuel for the injection.
My guess is that the description migrated to common rail system like lot of of other names.
Typical other example is how Whirpools are commonly called Jacuzzi.
 

bigb

2011 Winnebago Via 25Q on 2010 3500 Tucson, AZ
According to Stephens Service there were two service bulletins in 2018 about the bolts coming loose. He also says there is an updated stronger bolt but when I googled the part number he quoted .001.990.03.03 nothing comes up but that's not the first time a MB part number does not work on Google, what's up with that unless Tom is giving out incorrect PNs.
 

bigb

2011 Winnebago Via 25Q on 2010 3500 Tucson, AZ
Would it be OK to swap them out one at a time without having to reseal?
 

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