#7 Injector Leak

[Kenneth]

I have been experiencing a fuel leak from the #7 injector for about the last 2 or 3 months. The leak is not dripping, but I can smell diesel after I have driven the truck and there is also a very clean spot on the exhaust manifold below the injector. I have removed the fuel line nut and made sure the line was clean and was seated properly. I have also changed the fuel return line from the #5-7 injectors with the line from the #3-5 injector and the leak still seems to be at the #7 injector and did not change with the return line.

I just got off the phone with Bill from Heath Diesel and he suggested that I loosen the fuel line nut and tighten it several times to seat it properly, as well as use a carb or brake cleaner to clean and dry the area to see if I can see a fuel leak.

What I was wondering is if anyone can suggest any other ways to determine the source of the leak. Is it common to have a leaky injector? Bill said that it is very uncommon and that the likely culprit is the fuel line flange being warped and distorted from over tightening. Any ideas would be very much appreciated. Thanks.

BTW I replaced the injectors last May with stock output ones from Heath Diesel.

[rustyk]

You might try sprinkling talcum power underneath the suspect connector; it'll absorb the fuel and discolor if it's leaking.

[diesel65]

Check the rubber cap on the spare nipple of the #7 injector.

[chickenhunterbob]

I had a return line nipple itself (the metal part) come loose, where it seats in the injector body, don't know how, was about 10 months after I had changed them.

Come to think of it, was on hole #7 also.

At any rate wash it off, and watch where the fuel first appears.

[Kenneth]

Thanks for all the help guys. I am going to try loosening and tightening the fuel line a couple times as well as clean the area tomorrow. I drove my truck tonight and I think the leak is getting worse cause I can smell diesel pretty bad when I shut it off.

[Robyn]

As has been mentioned, the rubber cap on the back side of the injector is probably the culprit. The bypass hoses can alos leak. There is no pressure to speak of but if the rubber cap gives up they can leak enough to make a mess as well as smell things up pretty good. These little caps can be had from Ma General as well as our wonderful suppliers that advertise here.
I have in a pinch used a short chunk of the regular bypass hose and the top 3/4" of a 16 penny nail stuffed into the hose to stop up the leak on a rear injector.
The little caps are nice but not totally needed to make a repair that will work.

best

Robyn

[Kenneth]

Well today I went to look at the leak again, and right after I shut the truck off, I heard a hissing. I immediately pulled the return line from the #5-7 injectors, and the hissing stopped. I felt around the area of the injector, and there is a little bit of greasy diesel built up by the fuel line, but I got a fingertip soaked with diesel right underneath the return line on the #7 injector. So my guess is, like others have mentioned, the return line not sealing up to the nipple or a bad nipple.

Correct me if I am wrong, but if the nipple was bad wouldn't the hissing I heard still be hissing after I pulled the return line off?

I purchased the injectors from Heath Diesel and the set came with the "special" type of rubber so it doesn't need the retainer clamps on them. The plug on the #7 injector did come with the clamp, but the lines did not. So, could this leak be just as dumb as adding a clamp to the return line, or possibly a new return line as well?

I know I ramble a lot, but sometimes it helps for me to write out my thoughts. Thanks again for all the help.

[Kenneth]

Okay, so I have an update.

Turns out the fuel like I said before is actually leaking from the #7 return line. I went to the GM dealer and they said he would have to order one and it would cost #5. The parts guy gave me one more suggestion before I left, he said to try zip tieing the return line. Well, I tried and now the return line drips fuel. So, I called up Heath Diesel again, and he was more than happy to help me out. We discussed the history of the problem and what I ran into today, and what does he do? He is sending out a new injector with a new return line and a couple of clamps (to ease my mind) today!!

I can sincerely say that Heath Diesel has excellent service and help. I am happy with my purchase of their injectors and would do it again in a heart beat. Thank you again for all your help.

[Kenneth]

Well, I got the new injector and fuel return line from Heath Diesel on Monday and installed it today. I ran it a little on thte highway and around town and there are no leaks! The injector is dry and there's not anything wet around it.

Thanks again for all your guys' help. Sometimes I think I just use this forum for a sounding board. But all the input is much appreciated.

[chickenhunterbob]

Good news, leaks of any sort are an annoyance I just can't stand.

[Robyn]

Worst part of a diesel leak is that the nasty stuff stinks Not to mention it can burn if enough gets on the hot stuff.

Seen a Ford 6.9 going down the highway one night ahead of me and I could smell diesel real stong. All of a sudden there was flames coming out from under the thing. The fellow got it off the road and I pulled in behind and ran over with a fire bottle and we got it out.

It was a little return line that had ruptured and was spraying on the exhaust manifold.
We cut it off with a pocket knife and stuck it back on and he was off on to home with it.

Glad all is well

Robyn

[jerry598]

I think I'm having a similar problem. After nearly 2 months of non-use because of winter weather and high fuel prices, I was just walking past my truck and noticed an almost steady stream of diesel fuel dripping on the ground. Not a complete steady stream, but 4-5 drops per second. The truck had not been started in nearly 2 months! Looking at the rear 2 injectors on the driver's side, there seemed to be fuel oozing out around the return line clamps. I just replaced these injectors and return lines last fall. Got the return lines from my local Carquest dealer, they were specifically packaged and labeled for diesel fuel return lines. I put a pan under the leak right away and it collected about a pint of diesel before the leak stopped. Don't know how much ran out on the ground before I spotted the leak (its parked on a gravel driveway). Anyway, I'm about ready to tear into it and see if the return lines are truly the problem. Thanks for the advise on the talcum powder, I'll use that.

95 6.5 Turbo Diesel, 127k,
New injectors, dual stats, upgraded exhaust.