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  Topic Review (Newest First)
04-15-2015 10:43 PM
Catch-All Braggi nailed it. With the 99-2003.5 F-250 or F-350 7.3L engine, it's almost always the Fuel/ Drain Valve.

Plan A - Buy & install a new valve assembly from Ford dealer (approx $65) or from NAPA (approx $46) or from DieselORings.com
Plan B - Buy the three o-rings from DieselOrings for $6 + shipping. If you are in a hurry, you can buy two assorted size Viton (brown color) o-ring kits from Advance Auto for $7.99 per kit. Between the two kits, you will get the two o-rings of one size and one o-ring of smaller size that you need. Dieselorings.com has three grades of o-ring kits available - BEST Fluorosilicone (blue), BETTER brown Viton, GOOD Viton


DieselOrings has a comprehensive parts list that covers most of the common repair and maintenance problems you will encounter with the 7.3L engine.

My 2000 F-250 Lariat crewcab was leaking diesel intermittently for the last couple years. Even though I'd used Superchips to chip the truck several years ago, I began noticing the smell of raw diesel right after I'd changed out the fuel/ water separator filter. As part of the process, you have to cycle the fuel drain valve open to drain all the fuel (and any water) out of the fuel bowl. I think that's when the o-rings developed a slow leak.

I did a lot of research on the internets. Sites like this and YouTube helped me diagnose and narrow down the problem.

https://www.youtube.com/watch?v=-KXJWcg5_5I (from DieselTechRon)
this clip is particularly good because he deals with all THREE o-rings. There are two o-rings (see BEFORE pic) that are the same size. There is a smaller, thinner o-ring that is concealed inside the stem. When I dis-assembled the valve I found that the smaller, inner o-ring had been replaced with a cheap, non-fuel resistant rubber o-ring! That's where the leak was.

-one T20 Torx bit $2.49 (get the short one)
-the three o-rings (Advance Auto) $16.00
-36inches high-temp fuel hose 3/8" I.D. (for attaching underneath to bottom end of fuel drain tube)
-one set of three Finger Drivers from Toolworks #TW690 (for tight spaces) available at Advance Auto for $2.99

-without chipping the engine, the 7.3L engine F-250 should be giving you 20 mpg on the highway at 2000 rpm (approx 67-70mph depending on tire size & rear differential gear ratio).
-with the engine chipped for "towing" or economy mode with even a basic chipping module (I used Superchips), you should be getting approx 26-27 mpg highway at 70 mph/ 2000rpm.

I'm not even a Shadetree Mechanic but everything I've read on the internets says that the two main things that can adversely affect economy are a fuel/drain valve leak and a clogged EBPV Exhaust Back-Pressure Valve & Tube.

Last Summer the Fuel/Water Drain Valve was in a temporary non-leaking mode and I did an EBPV Valve Sensor replacement. I also used brake cleaner and a length of thick, ribbed weedwhacker line to ream out and clean out the EBPV tube that runs from the sensor to the exhaust. On a 186 mile trip from Louisiana to Gulf Shores Alabammy I used exactly 7 gallons fuel at 70mph the whole way. I topped off the 30 gl tank before I got on the highway and topped it off again with 7.0 gls in Gulf Shores after stop & go traffice down Rte 59 in summer traffic. That's 26.6 mpg fuel economy without having to deal with that politically-correct Exhaust Fluid BS being shoved down our throats by the Environmental Industry.

Here's the best video clip I saw for dealing with the EBPV issue:
https://www.youtube.com/watch?v=XLZI2wMpn5I (Trey Spooner)
Total Parts:
-Exhaust Back Pressure Valve sensor
-weedwhacker line
-can of Brake Cleaner

I hope all this helps!
12-08-2014 12:17 AM
Braggi Wow, thanks for this thread. I have a 2002 F350 and it's leaking at the fuel drain valve. Replaced the little piece of fuel line hoping that would stop it but no luck. So I did some searching and found this lovely little PDF with instructions to remove and replace the o-rings in the drain valve. Nice clear pics and good instructions. Also, the same company sells o-ring kits. Haven't checked the price yet but here's the PDF link: http://www.dieselorings.com/docs/FuelDrain.pdf
05-31-2013 03:53 AM
Originally Posted by klhansen View Post
No, in fact, you can't even buy the o-rings separate from Ford AFAIK. They just sell the whole valve.

Any place that sells o-rings can fix you up. Viton is the preferred material, but Buna-N has been working for me for quite a while (over 1-1/2 yrs). For Viton o-rings, try www.mcmaster.com or www.oringsusa.com
Yes,viton material is excellent,for some application Buna-N is enough.
05-07-2012 11:31 AM
SuperbeastVan Thanks for the reply!

I finally got a chance to see the leak as it was actually happening, now to just figure out where at the fuel bowl it's leaking. This thread is very helpful. Thanks guys!
05-04-2012 05:35 PM
1997 FORDF350PS I had a similar , hard to find leak,the drivers fuel return hose had rubbed on the hpop for many years and wore a small hole in the line, hard to see even running. I had to use a crows to loosen it, and make a 90 degree 9/16 open end to turn it off. You'll have that.
05-02-2012 12:07 PM
SuperbeastVan Hey everyone!

Sorry for bringing up an old thread, but I'm having a very erratic fuel leak that might be related to this and would like some help if possible.

I have a 2000 E350 with a 7.3 and every once in a while I will get a leak. Sometimes a small puddle after running it, some times, just a little spot on the ground and sometimes a gusher. I've found that with the gusher it is filling the valley under the turbo, but I cannot get the damned thing to leak when I have the dog box off. I cannot see any signs of a leak anywhere. Just wondering if anyone that has done this repair to the o-rings had the same type of symptoms? I need to fix this soon as fuel is too expensive to let run on the ground.

Thanks in advance for any help!
07-13-2011 04:34 PM
bugman What did he say was wrong with them? At one time you could buy the drain assembly from Ford and replace the whole assembly but I am not sure if it is still available. The only problem that I have heard with the fuel bowl or filter housing is pitting on the bottom of it to where it will start to leak in which case some have cleaned it real well and then placed JB Weld on it to seal it for while. If you do need to replace it I would suggest to get a hold of Mike R at Tousley Ford Parts Depot at 1-800-328-9552. They are a sponsor on the site here and sell parts at cost + 10% and should be able to help you. As far as replacing the housing or fuel drain if you can turn a wrench you should be able to replace it with no problems.
07-13-2011 04:10 PM
Fuel Leak Also. Please Help

I have a 97 F-250. Mechanic says fuel bowl and drain valve are bad. Quoted $700 to fix and replace both. Is this a really complicated fix or something a mechanically inclined person do? Any help would be greatly appreciated.
06-28-2011 06:15 PM
Knunch My 95 f350 7.3 required the fuel filter housing to be replaced. The canister was rotted through at the bottom. The guy who sold it to me had cobbled iT up with some kind of epoxy I think... and it went bad after a few months. Was over $300 to replace. I guess It pays to blow the water out thru the valve once in a while. There's at least a couple hose connects under the bottom that I thought must be leaking.....turns out pinhole leaks in the most expensive component,
06-19-2011 07:52 PM
PIPEPRO304 For what it's worth, my fuel leak was from the left fuel return hose, which had rubbed on the hpop for 14 yrs. and got a wear spot. I wrapped it(leak area)with some hi perf tape made for leaks, then put the id tag over the tape, and used a small hose clamp over the
tag, just to hold until I could get a new hose. I have the new hose, however, it will take a
crowfoot 12pt to loosen the 9/16 swivel fitting from the head, which I don't have, yet. I had a tuff time finding that leak.......
03-19-2011 12:51 PM
bozo 442
Originally Posted by jtownes14 View Post
Hey. I have a 1996 Ford F350 7.3 Power-Stroke. I have diesel puddled on top of my engine and disel dripping down on the trans and starter. Is this what you are referring to? HELP...

I have the same problem I replaced the o ring and the hoses it still leaks Helpppp. Bozo 442
09-22-2010 01:00 PM
jtgroover Thanks for the info
07-07-2010 08:53 AM
dlingner Trying to replace my fuel filter on a truck I bought this weekend. "Water in Fuel" light is on. My drain valve does not seem to want to open. Is there a trick to it? I am afraid to force it and break something...

My valve is black/grey and located in front passenger side of bowl.

Yesterday I went to replace the fuel filter, old one quite dirty, couldn't open valve so I sopped all fuel up in bowl with very clean rags. It will left about a 1/4 inch of liquid in the bottom. (Stuff in the way preventing getting rags all the way down there.) I put in new fuel filter. Now light goes off and on (mostly on) so I must have gotten some water out. Assuming I can get valve open, can I now just open it and let rest of water out?



95 F350 Powerstroke Crew Cab Dually Manual 5 Speed.
06-20-2010 11:11 AM
Originally Posted by musstag View Post
My 95 Ps 7.3 is leaking bad!! It began stalling now and then. Then I noticed stains on the driveway, thought tranny was leaking, it was diesel fuel. Its deep enuff in the block valley to splash with you fingers.... A mech has removed all but the filer housing and can't find the leak yet... what do you think, could this post be about what is wrong ???
I found the culprit/leak called the Fuel Restriction Sensor. Search this website. One post said prior to 97, it's located on the bottom of the fuel bowl. My 97 is on the top. On my way now to H Cheapo for the plug
05-13-2010 12:06 PM
gr8diver I got a 96 F250 4X4 7.3 with same leak....pooling by the turbo...it started when the filter was changed...I called a shop I use and the 2 fixes he gave was replacing/reseating the filter about $100 and lift pump about $750....
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