A lot of air in my fuel system.

Klem531 · **Posted:** Sat Oct 26, 2013 10:46 am

Hey fella's, my 06 CRD has been getting quite a bit of air in the system for some reason and I'm struggling a little bit to pin point the problem. It has 108k miles on it, Gen 2 fuel filter head, I did the timing belt / Water pump about 4 months ago at which time I replaced all the filters. Now with in the last 2 months I need to bleed the air out every couple weeks or so and its quite a significant amount. I've been pouring over the forum trying to find some ideas but everything so far checks out ok. I'm open to ideas/ suggestions...Thanks for any help.

thermorex · **Posted:** Sat Oct 26, 2013 11:04 am

Could be the fuel tank hose couplings or quick disconnects (the ones that go in the fuel line). Most folks take them out and use a regular hose with clamps. Installing an additional fuel pump (in tank or outside-inline) can also be very helpful.

Klem531 · **Posted:** Sat Oct 26, 2013 11:09 am

Ahhhhhhh.... I did not think to check that... Thanks

papaindigo · **Posted:** Sat Oct 26, 2013 2:41 pm

As I recall there are 2 quick disconnects back toward the tank. One is apparently accessible with the tank in place but the other requires dropping the tank. When dropping the tank you don't want much fuel in it due to the obvious weight issue. I don't have ready access to a post that provides a how to but as I recall you need to disconnect the fuel lines, probably an electrical connection to the fuel gauge sending unit, and the filler tube. Once done the rear tank straps can be undone and the tank lowered.

IMHO don't go cheap on fuel line, been there done that have the cracked line in the trash to prove it. Best get some marine grade diesel rated fuel; it will last forever and only costs a few bucks extra as you don't need much. Also don't cut the fuel line so you need fence stretchers to make it fit; a bit longer than minimum is desirable.

Those fittings are the usual source of air, other than the fuel filter head but... There are some possible sources in even the 2n gen filter head (inner gasket left on new filter install, leak at bleeder, leak at primer seal, filter not tightened enough) so you might want to stick a bit of clear vinyl tubing between the filter head and the inflow line to see if bubbles of air are coming in from there or "in front" of there before tackling the quick disconnect replacement.

Klem531 · **Posted:** Sat Oct 26, 2013 3:08 pm

Excellent information! Thanks a million... Come to think of it, now you've got me wondering about
The old gasket... Think I'll start there first. How about the water sensor in the bottom of the filter? Has that been known To be an issue? If memory serves, I had some trouble with that when I changed out my filter last time....

papaindigo · **Posted:** Sat Oct 26, 2013 3:29 pm

The original "inner" gasket that fits around the threaded center post that the filter screws onto can easily be left on when a new filter is installed in which case air will be a problem.

It's not impossible for a leak to occur at the WIF sensor but I'd think fuel out not air in. Easy enough to check as you will be able to see it when you pop the filter off the check that inner gasket.

jkbkwarner · **Posted:** Mon Oct 28, 2013 9:36 am

papaindigo wrote:

IMHO don't go cheap on fuel line, been there done that have the cracked line in the trash to prove it. Best get some marine grade diesel rated fuel; it will last forever and only costs a few bucks extra as you don't need much. Also don't cut the fuel line so you need fence stretchers to make it fit; a bit longer than minimum is desirable.

I second the quality of the fuel line. I was bitten by my negligence. The fuel line collapsed while I was driving and starved the engine. But I definitely recommend replacing the quick clips with hose clamps, once that was done problem was gone.

Klem531 · **Posted:** Sat Nov 02, 2013 7:29 pm

Well I finally found a few spare minutes in my crazy busy life to pull the filter. I was hoping to find that I left the old gasket on but no such luck.... Everything looked perfect! One thing I did notice was that the new filter I put on a couple of months back, came off a little easier than I would have liked it to. Also I typically use Napa filters and this one is a Mann... I seriously doubt that it had anything to do with it but just a thought. Needless to say, when I put it back on, I gave it another 2/3 of a turn.... We'll see what happens. Again, thanks for all the input!

Klem531 · **Posted:** Sun Dec 29, 2013 3:08 pm

Ok fella's I've dropped the tank and replaced the quick connects with fuel line and clamps...Still sucking air. Today I removed the filter head and disassembled it. I was a little surprised to find that the lower half that the filter seals against is plastic!!! I suspected that maybe the plastic housing wasn't sealing against the upper aluminum housing so I added some sealant to the rubber gasket and re-tightened the nipple that holds the two halves together....Still sucking air. I made sure that the copper gaskets on the in and out lines are clean and not damaged and that the sealing surfaces on the the filter head are clean and flat. Everything is tight! The bleeder valve looks pristine inside and out and appears to be seating fine in the bottom of the hole. I'm not really sure where to look next...Grrrr :banghead:

I noticed that on the factory fuel line that comes from the tank, there's a crimp where it changes from the steel line to the rubber that attaches to the fuel head. Anyone had a problem at that junction??? I feel as though I'm missing the obvious here. Thanks for any help or direction on this matter. Tony

amslube · **Posted:** Sun Dec 29, 2013 5:31 pm

I have a friend that had an air issue with a '96 Ram Cummins. That turned out to be a fuel line that had rusted through. I haven't heard of any rusted fuel lines on the Liberty CRD but it may be possible in the salt belt and the age of the vehicles now.

Klem531 · **Posted:** Sun Dec 29, 2013 5:33 pm

I considered that also.... My fuel lines are like new.

Klem531 · **Posted:** Sun Dec 29, 2013 5:43 pm

I just finished testing the filter head with my mighty vac vacuum pump that I use for bleeding brakes. I closed off the inlet side of the fuel head and attached the pump to the outlet. I put 15 in of vacuum on it and it held for quite some time. It did leak down about 2-3 in in a half hour but then again all the connections on the vac pump are just a plastic hose pushed on over a hose barb so I'm not surprised there was some leak down.... I'm leaning towards getting rid of the factory crimp from the steel line to rubber hose at the fuel head... Don't really know what else to try at this point...Ugh!

Hexus · **Posted:** Sun Dec 29, 2013 5:52 pm

Install a lift pump at the fuel tank and stop worrying about it.

Klem531 · **Posted:** Sun Dec 29, 2013 6:00 pm

I get the whole lift pump thing and it's looking like that's where this repair is headed. I just have a problem when it's worked fine for more than 100k MI and now all of a sudden it's sucking air... I don't like it when I can't figure out a seemingly simple problem.

CATCRD · **Posted:** Sun Dec 29, 2013 11:11 pm

Klem531 wrote:

I get the whole lift pump thing and it's looking like that's where this repair is headed. I just have a problem when it's worked fine for more than 100k MI and now all of a sudden it's sucking air... I don't like it when I can't figure out a seemingly simple problem.

Have you just tried a new filter yet? I know yours is only 4 months old, but it could still be clogged. I would try a new one before you go digging into fuel lines and lift pumps. If it's been running fine without any lift pump, it shouldn't just need one overnight. There must be a cause.

Klem531 · **Posted:** Sun Dec 29, 2013 11:25 pm

I picked up a new filter the other day just haven't put it on yet... I was really expectin that "AHHH HAAA" moment when I dug into to it this morning.. Lol. I'm. A little bit in denial that it could be the filter but I guess stranger things have happene.

steve@offroading.net · **Posted:** Wed Jan 15, 2014 11:42 am

Any updates on this? Having the same issues.

What type clamps did you use to replace the quick connects? Did you run new hose from the tank to the start of the solid pipes & use standard hose clips?

TIA

Klem531 · **Posted:** Wed Jan 15, 2014 12:03 pm

I never did find the source of the leak... I raised the white flag and and took Hexus 's advice and installed a lift pump outside of the tank and haven't had an issue. In fact I just made a 750 mile round trip to Northern Michigan last weekend pulling a 12ft Trailer and a 1000lbs of snowblower without so much as a hiccup. I sorta went cheap on the pump and bought a Mr Gasket diesel rated pump from Autozone. It works great it's just a little bit on the noisy side. To answer your question, yes I dropped the tank and removed both quick connects on the supply line. I used just plain old screw type hose clamps and doubled them up on the steel fuel line. There's not enough room to get 2 on the nipple that comes off the top of the tank. I happened to have heavy walled fuel line on hand so I used what I had. I called every parts store in a 50 mile radius and no one had diesel rated fuel line so we'll see. It really wasn't a big deal to drop the hitch and tank so my school of thought was if the lines don't hold up, I'll see if any of the area Marina's have any. Hope this helps. :-)

steve@offroading.net · **Posted:** Wed Jan 15, 2014 12:10 pm

Spot on thanks

Just been looking at fuel pumps too, think I will swap the hoses & install a pump at the same time & have done with the issue

Klem531 · **Posted:** Wed Jan 15, 2014 12:17 pm

A word of advice.... The hardest part was finding the dam wire under the back seat carpet for the fuel pump power. I found a step by step write up with pictures and you can get to the wire without removing the back seat. It's very difficult though. If I had to do it over again I would suck it up and remove the back seat.

A lot of air in my fuel system.

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