Got another P0087 today. So I'll check the fuel filter. Guy that owned it chaned it out and I bet he somehow didn't do it correctly

Inspect the o-rings closely that are associated with a filter change.

__________________
Jim

I replaced a supply hose to the filter because the original had a tear in it from non original hose clamps. I used a piece of hose and clamps from autozone. I'll replace the hose with the correct Mercedes molded hose and non reusable clamps.

Once buttoned up I noticed a bubble coming from the center plastic knob thing. Is it possible to just replace the o-rings since it's such a new filter?

Pretty sure this is what caused the P0087 code

I would think yes if they are properly sized.

__________________
Jim

Guess I'll see what harbor freight has as far as fuel resistant o rings

Why not your Honda dealer for parts?

__________________
'06 E320 CDI
'17 Corvette Stingray Vert

They might have o-rings but harbor freight is closer and I can buy the same assortment napa will sell.

Turning your nose to my honda sealing washers, which are nothing more than Bosch parts...

My cdi gets 35 mpg on highway/ city so far.

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

Au** Z*** has a pack of metric Orings for about $8.00. I use them for the oil filter stem on 617's & 616's when I change the oil. The kit has about 12 sizes, and about 20 of each size.

__________________

All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

The "center plastic knob thing" is the water sensor. It does take several o-rings that normally come with the filter kit. I would pull it and change out the o-rings.

The water sensor is removed by taking out the 2 Torx screws and rotating it to clear the tabs and then pull up.

The device at the top of the sensor is a vent, there is one of those in the box with the filter kit too. It just pulls off.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

^ I suspect those o-rings for the water sensor. That's what had the little bubble.


Also I need to invest in a quality set of e-torx, torx, and get more craftsman pro torx screw drivers

HF o-rings may not be the exact fit. If you do not have a new fuel filter/ o-rings, I would suggest just taking out the o-rings and inspect under a magnifier glass for damage. If they are smooth with no nicks, put them in boiling water for 5 minutes to un-crush and re-use. Also clean the o-ring seats and lube with diesel first. Maybe whoever installed that fuel filter did not do a good enough job keeping things clean and that's why it's leaking?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Stay away from the HF "star" bits and sockets. This is a patented fastener, and the Chinese knock-offs sold at HF are not the actual Torx pattern, so they do not fit properly.

I would get a good set of both genders (e-sockets and bits) from a reputable manufacturer like Lisle or Snap-on.

The guy who pulled his OM642 oil coooler a few months back learned that the hard way.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Mark

__________________
'06 E320 CDI
'17 Corvette Stingray Vert

I'll probably order a good set of torx and e torx sockets soon, I have SK and craftsman pro torx screwdrivers.


I just replaced my fuel filter o rings, had a rather visible leak so I replaced the 3 o rings for the fuel filter and after watching it idle for a few minutes IP close up showed no visible leaks so no more P0087 code...I used the harbor freight o rings.. Seeing as all of the o rings offered by autozone, advanced, and napa were all made in china I figured for $6 for a massive set, why not. If they crap out I'll order Mercedes Benz branded o rings

However after a test drive I instantly got a P0088 code, rail pressure too high. It's either the high pressure pump over compensating for a bum injector or the high pressure regulator going out. I'll dig around some more