Filter Housing dissected

BLake · **Posted:** Fri Mar 09, 2007 5:27 pm

I'm still getting air in the fuel so I did a little investigating. The filter housing is a new one but there was fuel collecting on top of the filter. The gasket between the housing and intermediate section appeared wet. I took the filter housing out and dissected it.

The whole assembly is very easy to remove. Unplug the sensors on the front, remove 2 13mm nuts from firewall bracket, lift out and up, unplug sensor on bottom. 2 minutes total time. Do this at filter change time and save yourself a lot trouble.

The filter was a bear to remove. No way it would have come off in the car. The sandwich plate rotated when I tried to remove the filter. The feed pipe in the center comes out with an 8mm allen. It was glued or locktited in. Someone mentioned that they re-torqued this plug until it squealed. That was the tocktite talking. The threads in the housing were very poorly taped. Deep threads on one side, barely formed threads on the other. I spent two hour chasing down an M16x1.5 tap to fix the threads. Permatex Indian Head sealant is the only thing I could find that was listed as diesel compatible so that is what I used to put it back together. The pipe will probably come out when I change the filter, I need to find something that will lock it in place. It will take a day or so to see it this did any good.

Things I learned, in no particular order:
The sandwich plate is PLASTIC. This is were the fuel temp and heater plug in. Heat+plastic not good, I see more problems with this in the future. It is useless to apply a bunch of torque to the center pipe. I just flexes and doesn't tighten anything.

The gasket seating surfaces on the housing are as cast and painted. In other words, rough with a poor seating/sealing surface. In a suction feed system, this should have been machined to ensure positive sealing.

There seems to be a check valve on the feed side. This should keep the feed line full of fuel. This info will be useful for future leak checking. I need to fabricate some hoses with the proper ends so I can put a vacuum on the filter to test it. Plug for the feed side, 3/8" clear hose with a barbed fitting(correct size for vac, hose) on the supply side. Apply vacuum, see it it holds/watch for air bubbles.

The pipe in the center would be very easy to machine for use with another type of filter. M16x1.5 on the housing side+shoulder+whatever thread on the filter side. Removing this little pipe will be more work than just remove and replace. You have to chase the thread to remove the old sealant. A pocket knife won't scrape it off.

Now that I think about it, the center pipe only holds the center section in place. When you tighten the filter, it tightens the center section. I would not try to tighten the center pipe to get it to seal better. All you will do is crack the plastic and it won't help a thing.

Conclusion:
This whole setup is of poor quality and materials. If it gives me any more problems, I'm going to replace it with a Racor 200 series filter housing. It has a bowl to check for water, a heater option, a primer pump and looks about the same size. With some 90 degree fittings, should bolt right in. 2 micron filters available all day long.

Don't tighten the center section, no good will come of it.

Sorry no pictures, my hands were coated in fuel and I didn't want to mess up the camera.

DarbyWalters · **Posted:** Fri Mar 09, 2007 6:22 pm

That is just DEPRESSING :evil:

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Thanks for the info. Another project coming up. Have you picked any particular Racor model that will accept the CAT 2 filters yet? Might be easier just to go ahead and change it out wholesale instead of futzing around with it.

BLake · **Posted:** Fri Mar 09, 2007 6:59 pm

Anything wrong with Racor 2 micron filters that I don't know about? I live in a big boating area, these filters are available everywhere.

BlackLibertyCRD · **Posted:** Fri Mar 09, 2007 11:16 pm

I been thru it and even tried using sealant on the upper seam. It not nearly as bad as it was but still have a little air problem time to time. Let me know how the Racor 2 micron filters work out.

oldnavy · **Posted:** Fri Mar 09, 2007 11:44 pm

And just about the time I thought things were looking up. :roll:

retmil46 · **Posted:** Sat Mar 10, 2007 12:53 am

In other words, you have to monkey torque the filter on with a strap wrench to get the filter head to seal itself? :shock:

Just bloody wonderful. :evil:

I've been looking thru the FSM, researching any potential problems with replacing the factory filter head with a Racor or something similar.

One potential problem I've come across is the fuel temp sensor. According to the FSM, the ECM uses the fuel temp sensor to adjust pressure in the high pressure rail, and also fueling to the engine. Don't know what effect this would have if the ECM didn't have the temp sensor input.

If it wasn't for that, I'd already be shopping for a Racor or Davco unit to put in this beast.

BLake · **Posted:** Sat Mar 10, 2007 9:59 am

Monkey torque all you want but keep in mind you are squashing a flimsy piece of plastic. The sandwich plate is very lightly constructed.

I didn't think about the temp sensor and ECU. I could pull the sensor out and duct tape it to the fuel line :lol:

The filter top and O rings were wet with fuel this morning so it did no good. Maybe there is a crack in the housing. I don't see any fuel near the sensors. It's going to be a few days before I can make the hoses for a vacuum test rig but I'll report back when I know something.

oldnavy · **Posted:** Sat Mar 10, 2007 10:02 am

retmil46 wrote:

In other words, you have to monkey torque the filter on with a strap wrench to get the filter head to seal itself? :shock:

Just bloody wonderful. :evil:

I've been looking thru the FSM, researching any potential problems with replacing the factory filter head with a Racor or something similar.

One potential problem I've come across is the fuel temp sensor. According to the FSM, the ECM uses the fuel temp sensor to adjust pressure in the high pressure rail, and also fueling to the engine. Don't know what effect this would have if the ECM didn't have the temp sensor input.

If it wasn't for that, I'd already be shopping for a Racor or Davco unit to put in this beast.

I was looking at that last night and wondering if we have a real problem if sensor is disconnected or fails. I would think it would set to a default minium pressure and possible causing a "limp in mode" to be set. If that is correct we have a major probem replacing the unit completely with no easy work around w/o reprogramming the ECU.

I am beginning to really regret selling my MB 240D, but then I would have had some seal problems with the ULSD switch so I guess nothing os perfect. Now I am thinking again about getting rid of the Jeep. I am getting tired of having to do all these mods to work around poor engineering from D/C with outlook of even less help in the future on the diesel.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

One potential problem I've come across is the fuel temp sensor. According to the FSM, the ECM uses the fuel temp sensor to adjust pressure in the high pressure rail, and also fueling to the engine. Don't know what effect this would have if the ECM didn't have the temp sensor input.

The fuel heater in the CRD is also listed as thermostatically controlled - no doubt this same temperature sensor is used to control how much to heat the fuel in cooler temps. This sensor is probably a must have mod to any replacement fuel filter.

retmil46 · **Posted:** Sat Mar 10, 2007 11:49 am

oldnavy wrote:

I was looking at that last night and wondering if we have a real problem if sensor is disconnected or fails. I would think it would set to a default minium pressure and possible causing a "limp in mode" to be set. If that is correct we have a major probem replacing the unit completely with no easy work around w/o reprogramming the ECU.

I am beginning to really regret selling my MB 240D, but then I would have had some seal problems with the ULSD switch so I guess nothing os perfect. Now I am thinking again about getting rid of the Jeep. I am getting tired of having to do all these mods to work around poor engineering from D/C with outlook of even less help in the future on the diesel.

At one time, I was being asinine and threatened to coat the entire filter head in JB Weld to seal the bloody thing up. Beginning to wish I'd kept my mouth shut.

Probably could find a way around this - if you could get the electrical/electronic specs on the sensor and heater, there's the possibility of finding the same type sensor and heater packaged such that they could be installed in the threaded option ports on a Racor or similar unit, from one of the electronic supply companies such as Digikey or Mouser.

But as you said, once again we're talking about more reverse engineering just to keep the beast running reliably, and the list is getting rather long.

oldnavy · **Posted:** Sat Mar 10, 2007 12:42 pm

retmil46 wrote:

oldnavy wrote:

I was looking at that last night and wondering if we have a real problem if sensor is disconnected or fails. I would think it would set to a default minium pressure and possible causing a "limp in mode" to be set. If that is correct we have a major probem replacing the unit completely with no easy work around w/o reprogramming the ECU.

I am beginning to really regret selling my MB 240D, but then I would have had some seal problems with the ULSD switch so I guess nothing os perfect. Now I am thinking again about getting rid of the Jeep. I am getting tired of having to do all these mods to work around poor engineering from D/C with outlook of even less help in the future on the diesel.

At one time, I was being asinine and threatened to coat the entire filter head in JB Weld to seal the bloody thing up. Beginning to wish I'd kept my mouth shut.

Probably could find a way around this - if you could get the electrical/electronic specs on the sensor and heater, there's the possibility of finding the same type sensor and heater packaged such that they could be installed in the threaded option ports on a Racor or similar unit, from one of the electronic supply companies such as Digikey or Mouser.

But as you said, once again we're talking about more reverse engineering just to keep the beast running reliably, and the list is getting rather long.

My guess is the only work around is to just have a new filter head machined and use the OEM sensor housing, unless one of those can be remanufactured in aluminum and the sensors switched over from the plastic sensor.

I am just hoping that some were poorley made and that is the only problem, and not all of the filter assembly's may have the same problem.

retmil46 · **Posted:** Sat Mar 10, 2007 12:54 pm

I'm going to order a new filter head, just to be on the safe side.

One thought that has occurred to me - might the leakage past that rubber gasket be due to shrinkage from ULSD, same thing that happened years ago when they made the switch to LSD? If that's the case, then perhaps just a new rubber gasket may cure the problem.

Seems like this problem has only reared it's head since they started bringing ULSD on line, with older CRD's that got ran on LSD for a while. But given the history of this beast, I'm not betting on the easy fix.

Kellog13 · **Joined:** Sat Jan 27, 2007 9:21 pm **Posts:** 74

Nice write up Blake. Pretty much sums up the whole vehicle.

oldnavy · **Posted:** Sat Mar 10, 2007 5:32 pm

retmil46 wrote:

I'm going to order a new filter head, just to be on the safe side.

One thought that has occurred to me - might the leakage past that rubber gasket be due to shrinkage from ULSD, same thing that happened years ago when they made the switch to LSD? If that's the case, then perhaps just a new rubber gasket may cure the problem.

Seems like this problem has only reared it's head since they started bringing ULSD on line, with older CRD's that got ran on LSD for a while. But given the history of this beast, I'm not betting on the easy fix.

I have been running ULSD for about 3 months now and have had no leakage, so I kind of doubt that is the problem.

retmil46 · **Posted:** Sat Mar 10, 2007 8:43 pm

Think I may have found a simple fix on this beast. Don't have time to go into it right now, have to eat and make another run to the parts store, but it's so oddball even I can scarcely believe it just might work.

oldnavy · **Posted:** Sat Mar 10, 2007 8:48 pm

retmil46 wrote:

Think I may have found a simple fix on this beast. Don't have time to go into it right now, have to eat and make another run to the parts store, but it's so oddball even I can scarcely believe it just might work.

Oh crap we are in for it now!!!

Dive! Dive! :wink:

retmil46 · **Posted:** Sun Mar 11, 2007 1:00 pm

oldnavy wrote:

retmil46 wrote:

Think I may have found a simple fix on this beast. Don't have time to go into it right now, have to eat and make another run to the parts store, but it's so oddball even I can scarcely believe it just might work.

Oh crap we are in for it now!!!

Dive! Dive! :wink:

Sounds like something a skimmer would say. :wink:

I've found a ready-made gasket to replace the one between the two sections of the head, same diameter and thickness but taller, so you can get more compression on the gasket and a better seal.

It's the outer gasket from the Mopar fuel filter that I just removed from the beast. :shock:

When I pulled the filter head apart yesterday and removed the gasket from between the two sections, I noticed that it looked exactly like the outer gasket on a fuel or oil filter. I still had the old Mopar filter laying around, and in one of those brief flashes of intuition got the idea to see if the outer gasket from the fuel filter would fit.

It did. The gasket from the fuel filter is 1/16" or more taller than the filter head gasket, such that you can get close to 1 1/2 turns of compression on the gasket before the center pipe and lower section of the filter head bottom out against the top section of the head.

My filter head looks to be better built than Blake's. After cleaning out the threads, just running the center pipe into the upper section of the head, it went 6 turns before the center pipe bottomed out on the end of the threads in the hole. When adding on the lower heater section, the center pipe went 3 1/2 turns before the lower section was up hard against the upper section.

With the original head gasket in place, it wouldn't start to grab and compress until the last 1/2 turn of travel on the center pipe. But with the gasket from the fuel filter, it's making contact and starting to compress a good 1 1/2 turns before the end of travel. If you look at any fuel or oil filter, they always direct you to tighten the filter at least 3/4 to 1 turn after the gasket makes contact to get a good seal.

Could it be that bloody simple - that all we need is a taller gasket, and to change it out regularly along with the fuel filter - to keep this beast from leaking? Guess I'll find out.

For those that don't have a spare Mopar filter laying around, I did a little cross-checking with some of the filters I picked up to experiment with. The gasket from the Wix equivalent to the Cat filter, P/N 33528, is an exact match to the one on the Mopar filter - same diameter, thickness, and height. Might seem like a waste, buying a $15 fuel filter just to get the gasket off of it, but's that's a sight better than spending $150 for a new filter head.

On another note, I pulled the bleed screw out of the filter head. It looks to be nothing more than a standard brake bleed screw, most likely 10 MM. I'm going to pick up some generics at the parts store and see if these will fit. If so, we'll have a ready replacement for the original if it gets worn and starts weeping.

oldnavy · **Posted:** Sun Mar 11, 2007 2:20 pm

retmil46 wrote:

oldnavy wrote:

retmil46 wrote:

Think I may have found a simple fix on this beast. Don't have time to go into it right now, have to eat and make another run to the parts store, but it's so oddball even I can scarcely believe it just might work.

Oh crap we are in for it now!!!

Dive! Dive! :wink:

Sounds like something a skimmer would say. :wink:

I've found a ready-made gasket to replace the one between the two sections of the head, same diameter and thickness but taller, so you can get more compression on the gasket and a better seal.

It's the outer gasket from the Mopar fuel filter that I just removed from the beast. :shock:

When I pulled the filter head apart yesterday and removed the gasket from between the two sections, I noticed that it looked exactly like the outer gasket on a fuel or oil filter. I still had the old Mopar filter laying around, and in one of those brief flashes of intuition got the idea to see if the outer gasket from the fuel filter would fit.

It did. The gasket from the fuel filter is 1/16" or more taller than the filter head gasket, such that you can get close to 1 1/2 turns of compression on the gasket before the center pipe and lower section of the filter head bottom out against the top section of the head.

My filter head looks to be better built than Blake's. After cleaning out the threads, just running the center pipe into the upper section of the head, it went 6 turns before the center pipe bottomed out on the end of the threads in the hole. When adding on the lower heater section, the center pipe went 3 1/2 turns before the lower section was up hard against the upper section.

With the original head gasket in place, it wouldn't start to grab and compress until the last 1/2 turn of travel on the center pipe. But with the gasket from the fuel filter, it's making contact and starting to compress a good 1 1/2 turns before the end of travel. If you look at any fuel or oil filter, they always direct you to tighten the filter at least 3/4 to 1 turn after the gasket makes contact to get a good seal.

Could it be that bloody simple - that all we need is a taller gasket, and to change it out regularly along with the fuel filter - to keep this beast from leaking? Guess I'll find out.

For those that don't have a spare Mopar filter laying around, I did a little cross-checking with some of the filters I picked up to experiment with. The gasket from the Wix equivalent to the Cat filter, P/N 33528, is an exact match to the one on the Mopar filter - same diameter, thickness, and height. Might seem like a waste, buying a $15 fuel filter just to get the gasket off of it, but's that's a sight better than spending $150 for a new filter head.

On another note, I pulled the bleed screw out of the filter head. It looks to be nothing more than a standard brake bleed screw, most likely 10 MM. I'm going to pick up some generics at the parts store and see if these will fit. If so, we'll have a ready replacement for the original if it gets worn and starts weeping.

Measure that gasket then go to McMaster-Car or local tractor supply and locate one for replacement.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

And, I'm guessing that this fixed the leak you had once you installed the NH filter? Sounds like it did, since you didn't say otherwise. With all of this experimentation, we need to start our own parts catalog. :-)

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