Durmax LLY Losing prime

[MO_Trout_Bum]

Just wanted to get some thoughts on a sporadic problem. After an uneventful 3 hour drive back from camping, we dropped off the camper at the storage lot (truck was idling about 10 minutes); put the truck in gear and it immediately died. Would turn over but not start. All that occurred to me was, it lost prime. So I loosened the bleeder and pumped a few times (no air came out). Left it sit another minute or two and primed again, and diesel came shooting out of the bleeder. Tightened it up, and the truck started right up. Drove home and put the truck in the garage until I had time to work on it. Replaced the fuel filter as a precaution (I had just replaced < 2000 miles ago in the Fall), primed it and it started right up. Noticed some sediment in the drain pan, but not sure that is unusual. Anyway, finished the job, primed as normal and truck started right up. Truck sat in garage another week, and I took it today to the storage lot to do some camper maintenance for a couple of hours. Started truck up, put it in gear and it died. Very same scenario with the bleeder as previously... truck start up and I took it to get some fresh diesel (about 15 gallons); drove it down the interstate 5 miles or so and back, ran some errands, and no problems since. Just wondering if we got some bad diesel on the trip, or sediment in the tank from truck sitting in garage for most of the winter, or ????

Any thoughts or similar experiences?

[_40Fan]

We had one of customers back in last week that had a previous issue of loosing prime, but we couldn't find the issue then. This time we were able to keep it all day long. Every time I would walk by it, I would pump the primer button and do a check for leaks. At the end of the day, it finally started leaking around the heater connector on top of the filter housing. Napa sells a rebuild kit that comes with all of the O-rings needed as well as a brass bleeder screw.

[MO_Trout_Bum]

Just following up with a quick progress report. Replaced the filter housing as planned (2 hour job) last week. Took a three hour trip over the fourth, towing heavy in hot weather, and lots of stopping and starting over six days of camping and fly fishing. So far so good!

Btw, for anyone else doing the same fix, do yourself a favor and pick up a couple of replacement hose clamps (screw type) at an auto parts store, as there is very little room to work on it to begin with and the factory pinch clamps were hard to work with.

Thanks again to all!

[GoPackGo]

After what happened to my OEM plastic version, I am of the opinion that everyone should replace the plastic bleeder screw as a preventive measure.

Plastics vs metal ??????

[caberto]

I've had this same issue sporadically - mostly when towing but very seldom. I finally looked it up and read recommendations. First and cheapest fix was to replace the plastic bleed screw. Mine was pretty beat up so I ordered a metal one and put it on; the issue has not repeated since, but it hasn't been very long either, so I don't really know if it fixed it yet.

Next will be replacing the entire filter head and WIF sensor as you did if the issue persists. Thanks for the link!

[MO_Trout_Bum]

Michelle.S wrote:
Was just having nearly the same issue with my '11, turns out it was actually leaking thru the Water in Fuel sensor in the bottom of the filter, was draining the fuel from the filter.

Thanks for passing this on! And, thanks again to everyone for your guidance. So, here is what I decided to do based on everyone's feedback and my own research. Brand new GM part #12642623 which replaces the entire filter head and WIF sensor, and includes a new Delco filter which I intend to use as a spare. All for $108 through Amazon Prime. It was either this or invest $30 in a re-build kit and maybe $30 for the WIF. Price from GM dealer was $161 + tax.

https://www.amazon.com/General-Motors-Fuel-Filter-12642623/dp/B00CMUCHHK/ref=sr_1_1?s=automotive&ie=UTF8&qid=1467129746&sr=1-1&keywords=12642623

I may end up replacing the tank level sensor as well, if this doesn't do the trick. However trying the easiest fixes first....

[Michelle_S]

Was just having nearly the same issue with my '11, turns out it was actually leaking thru the Water in Fuel sensor in the bottom of the filter, was draining the fuel from the filter.

[Grit_dog]

GoPackGo wrote:
I had an '02 and it had a PLASTIC bleeder valve. They break/crack and allow air to get into the system. Mine actually broke in half as I was removing it to replace with a steel valve. If you have a plastic bleeder valve, replace it with an after market steel version. As I recall, there was also a small o-ring on the bleeder valve - maybe that's gone bad. If not that, then a filter O-ring may be the culprit.

Was going to suggest this. My Dmax had the same issue. Or it could be the primer diaphragm or the wif sensor on the bottom of the filter.

[GoPackGo]

I had an '02 and it had a PLASTIC bleeder valve. They break/crack and allow air to get into the system. Mine actually broke in half as I was removing it to replace with a steel valve. If you have a plastic bleeder valve, replace it with an after market steel version. As I recall, there was also a small o-ring on the bleeder valve - maybe that's gone bad. If not that, then a filter O-ring may be the culprit.

[_40Fan]

He is referring to the in tank unit.

[MO_Trout_Bum]

6.6 Oilburner wrote:
Look for anywhere in the fuel system that could be drawing in air. Everyone throws a rebuild kit in the filter housing as a first step because its cheap and easy, it seldom fixes the problem. I've changed more sending units than rebuilt fuel filter housings.

Thanks to everyone for your thoughtful responses. Looks like most are thinking fuel filter housing so far.

6.6 thanks for the additional guidance. Are you referring to the tank level sensor or is there another sensor/sending unit under the hood?

[6_6_Oilburner]

Look for anywhere in the fuel system that could be drawing in air. Everyone throws a rebuild kit in the filter housing as a first step because its cheap and easy, it seldom fixes the problem. I've changed more sending units than rebuilt fuel filter housings.

[Cameo_Phil]

You probably need to rebuild the fuel filter housing. "O" rings and seals get old and leak air into the housing. Rebuild kits are available to do this job.

[_40Fan]

We have had a handful of these coming in the shop the last two weeks. Temp recently started hovering in the high 90's. Two of them needed housings, but the other three or four we just reprimed and away they went.

[JoeGood988]

Same thing happened last Monday...started then died....no fuel coming through....priming only worked short time...Took it to Chevy dealer and fuel filter housing was bad....something with the primer ball and something else in the filter assembly...anyway...works fine now