Durmax fuel filter head rebuild

zmetzing 2017-12-17 05:46:40 UTC #1

Last weekend, my truck died within 10 seconds of starting as I was re-positioning it do some work on another vehicle. I was able to start it after re-priming it with the hand pump, which points to a loss of prime.

Installing a clear section of fuel hose between the filter head and the CP3 intake revealed many bubbles.

One $12 o-ring and aluminum bleeder screw kit later, no more bubbles. However, there is a significant restriction still to be identified (see the static vacuum bubble on the left hand side that the air bubbles pass through). The youtubes suggest a collapsed hose or clogged fuel pickup somewhere upstream, so more work is to come.

TLAR 2017-12-17 07:51:08 UTC #2

Have you eliminated the air entering the fuel feed/supply system?

TBJK 2017-12-17 15:09:36 UTC #3

I am not too sure on chevy’s but you may have a clogged pre-filter screen in the tank. Diesel can be bad about getting growth in the tank if you’re not careful. That maybe enough to give you cavitation.

Tres0422 2017-12-17 15:19:24 UTC #4

Tim beat me to it, but those “socks” around the pickup or in-tank pumps are usually a clogged mess…

zmetzing 2017-12-17 16:20:46 UTC #5

Yeah, not looking forward to dropping the tank. :-\

jast 2017-12-17 16:26:34 UTC #6

Could always pick up the bed…

TLAR 2017-12-17 16:38:20 UTC #7

If it is a Texas or southwest truck, raising the cargo bed is definitely the way to go.
I’ll help!
If the truck is from the rust belt then dropping the tank may be your only realistic option.

zmetzing 2017-12-17 17:12:57 UTC #8

I’ve found a couple of sites which recommend dropping the tank to ensure it is fully clean after the job. That seems like a good idea to me. Any reason (other than difficulty) not to do so?

I’ll likely replace the fuel sender, gaskets, etc. while I’m in there. I also have a in-line lift pump and fuel/water separator filter to install on the frame rail. This will likely be a weekend job after the new year, as the truck won’t see any action until then.

I would gladly accept the help!

TBJK 2017-12-17 17:59:46 UTC #9

I’ll give you a hand. I find it more enjoyable working on other vehicles than mine.

All 3 of mine have a laundry list of items to do.

zmetzing 2017-12-18 02:26:19 UTC #10

Bubbles have returned on the filter head output, and a clear line installed on the supply side of the filter head is full of fuel with no bubbles, so the leak persists within the filter head.

Since all new o-rings were installed, only a few things remain which might be the cause: water-in-fuel sensor leak, cracked fuel heater, or a crack in the filter head itself.

WIF plug ordered, which will hopefully shore things up.

JRay 2017-12-18 03:22:11 UTC #11

I had a prefilter clog on my old f350 once. That was a nightmare. I was on my way to my paramedic exam when it happened…

The key symptom I learned to IDing an algae problem clogging a prefilter was that if you let it "rest, fuel would slowly work its way back into the fuel system, but after a brief run, say out of your neighborhood, it would starve. Then you couldn’t get it restarted.

Adam_Oas 2017-12-18 20:01:21 UTC #12

Me too. If you get into something that’s above your own head or are missing parts - get deep enough that you should abandon hope - or whatever, you can always drive away in your own car…

chadsykora 2017-12-21 02:14:58 UTC #13

Not sure what year of Duramax you have, however, the fuel filter assembly is notorious for giving similar issues (as mine did)…before going much further, I would strongly recommend making sure you have installed the following kit:

For the money, it is a relatively inexpensive way to eliminate this as a very common issue…worked great for me as I was having issues - especially in warmer weather with it losing pressure. This fixed me 100%.

If pressing the primer button a few times will get you started again, I would say this is , at the very least, a “smoking gun” to look at.

zmetzing 2017-12-21 03:57:41 UTC #14

Yep, I’ve rebuilt the filter head with o-rings and the aluminum bleeder screw. I’m waiting for the WIF plug to be delivered, which might be the actual leak point.

zmetzing 2018-01-12 01:15:09 UTC #15

The WIF plug did not solve the issue, but a new filter head did. No more bubbles at all. The skinny factory fuel lines were replaced with Gates 5/8" fuel line and were secured with proper screw-type hose clamps.

Victory!