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Hello everyone. I just purchased my second 7.3 OBS, a 1995. When I first checked it out, she ran pretty well. Started a little hard, but the engine sounded good. My other truck is a '97 and runs near perfectly, so I felt that I knew what a healthy 7.3 sounded like. The vehicle wasn't tagged, and had sat up for several years. It's a long story but the reasons for that all checked out (older gentlemen had it, had health and financial troubles) . I'm only the 3rd owner, its got 160,000 miles on it. On the day I picked it up, the former owner said it was running a little rough, and he thought maybe an injector was going bad. I started it up, and indeed it was running rough, blowing white smoke, and had almost the sound of a miss. You could hear a hissing sound with every revolution. Nothing like the day I test drove it. But, I still wanted it! So, I had it put on a flatbed, and once home I got to looking into it and noticed oil on the drivers side valve cover, coming out of the crank case ventilator. That was alarming but the hissing noise I was hearing really had me concerned, so I had the truck running and was giving it some throttle, just to see if the sound changed or went away with higher RPM and all of a sudden the noise changed to a clanging. It sounded horrible. I put my hand on the valve cover and could feel the vibration. I shut the truck off and decided I would pull the cover off and just see if I could see anything amiss. I did not see anything abnormal initially, but I've also never had one off. I did notice a glow plug wire was not attached to the cap on top of the plug, but, I just wasn't sure what I was looking at right then. I tried starting the truck up with the cover off to get a look that way, and something shot right out! Lo and behold the glow plug where the wire I had seen broke had come right out. Only the element came out though. The shaft part was still inside the head. I removed it easily, as it was already loose. I compared what came out to a picture of a new Motorcraft plug and realized the last section, or tip of the glow plug, was missing. So, my question is: Has anyone seen a glow plug fail right at the tip like that? Air from the cylinder was coming through it, I believe, and causing that hissing noise and subsequent banging noise. You could even see under the valve cover where the element appears to of been banging up against it. Now I'm trying to decide what to do about the part I think is still stuck in there. If I shine a light down in the glow plug hole, it's not smooth the entire way, there is a ridge a little ways down which I think is the top of that stuck tip? It's an autolite plug..go figure. I read somewhere they are notorious for this? I have a borescope on the way, and thought about taking the injector out, trying to get that piece to go down further to where I could use a magnet maybe to fish it out? Probably farfetched, and the head will likely need removed...but thought it was worth a try. Any insight or thoughts are appreciated. Thanks..
Last edited by Powerstroke28RYR; Dec 13, 2020 at 09:14 PM.
Reason: spelling
Hello everyone. I just purchased my second 7.3 OBS, a 1995. When I first checked it out, she ran pretty well. Started a little hard, but the engine sounded good. My other truck is a '97 and runs near perfectly, so I felt that I knew what a healthy 7.3 sounded like. The vehicle wasn't tagged, and had sat up for several years. It's a long story but the reasons for that all checked out (older gentlemen had it, had health and financial troubles) . I'm only the 3rd owner, its got 160,000 miles on it. On the day I picked it up, the former owner said it was running a little rough, and he thought maybe an injector was going bad. I started it up, and indeed it was running rough, blowing white smoke, and had almost the sound of a miss. You could hear a hissing sound with every revolution. Nothing like the day I test drove it. But, I still wanted it! So, I had it put on a flatbed, and once home I got to looking into it and noticed oil on the drivers side valve cover, coming out of the crank case ventilator. That was alarming but the hissing noise I was hearing really had me concerned, so I had the truck running and was giving it some throttle, just to see if the sound changed or went away with higher RPM and all of a sudden the noise changed to a clanging. It sounded horrible. I put my hand on the valve cover and could feel the vibration. I shut the truck off and decided I would pull the cover off and just see if I could see anything amiss. I did not see anything abnormal initially, but I've also never had one off. I did notice a glow plug wire was not attached to the cap on top of the plug, but, I just wasn't sure what I was looking at right then. I tried starting the truck up with the cover off to get a look that way, and something shot right out! Lo and behold the glow plug where the wire I had seen broke had come right out. Only the element came out though. The shaft part was still inside the head. I removed it easily, as it was already loose. I compared what came out to a picture of a new Motorcraft plug and realized the last section, or tip of the glow plug, was missing. So, my question is: Has anyone seen a glow plug fail right at the tip like that? Air from the cylinder was coming through it, I believe, and causing that hissing noise and subsequent banging noise. You could even see under the valve cover where the element appears to of been banging up against it. Now I'm trying to decide what to do about the part I think is still stuck in there. If I shine a light down in the glow plug hole, it's not smooth the entire way, there is a ridge a little ways down which I think is the top of that stuck tip? It's an autolite plug..go figure. I read somewhere they are notorious for this? I have a borescope on the way, and thought about taking the injector out, trying to get that piece to go down further to where I could use a magnet maybe to fish it out? Probably farfetched, and the head will likely need removed...but thought it was worth a try. Any insight or thoughts are appreciated. Thanks..
well, I’m not totally sure if the lip I’m seeing is the top of the tip, where it’s swollen but the bottom part is gone so I can see through it, or if that lip is where the glow plug seats and the tip has actually burned off entirely.
well, I’m not totally sure if the lip I’m seeing is the top of the tip, where it’s swollen but the bottom part is gone so I can see through it, or if that lip is where the glow plug seats and the tip has actually burned off entirely.
Do you have another glow plugs to try? It will tell you right away if it's still in the head. Hopefully you don't have a damaged cylinder from the tip bouncing around inside the cylinder.
Do you have another glow plugs to try? It will tell you right away if it's still in the head. Hopefully you don't have a damaged cylinder from the tip bouncing around inside the cylinder.
I have some on order. Should be here by weeks end. I’m hopeful there’s no damage either! Someone said it’s not uncommon for a aftermarket plug to burn off... so perhaps it just fell apart?
I had the exact experience with my E99, found everything but the tip, about 20,000 miles later it still puffs white smoke for about 1 mile on the first start of the day.
I never even put a scope down it as when it happened I was in a spot where I couldn't safely get off the road so I drove it home about 15 miles. opened the hood and could see the dimples in the valve cover. removed it picked up the pieces of the old glow plug, installed new glow plug, been using it since.
I had the exact experience with my E99, found everything but the tip, about 20,000 miles later it still puffs white smoke for about 1 mile on the first start of the day.
I never even put a scope down it as when it happened I was in a spot where I couldn't safely get off the road so I drove it home about 15 miles. opened the hood and could see the dimples in the valve cover. removed it picked up the pieces of the old glow plug, installed new glow plug, been using it since.
Ha! Glad to know I’m not the only one that’s happened to. I was able to get all 4 out on the drivers side. One of them was a huge pain, as it was stuck really bad. Waiting on new ones (Motorcraft) to come in the mail.
I just wanted to close this thread by thanking everyone who responded and to give an update and maybe info to help the next person.
. I changed the drivers side glow plugs successfully, and replaced the valve cover/wiring harness. FYI: the glow plug that came apart, cylinder #4, and the plug at cylinder #8, both came out easy. They were basically loose and could be taken out without force. Cylinder #2 plug was swollen, and I had to turn it back and forth and I used Aerokroil creeping oil to try to help break up the carbon. Not sure if it helped or not but I ended up finally getting it to come out by continuing to unscrew it with a socket wrench. Cylinder #7 plug was the sketchy one. When I started to loosen it, it made this creaking sound like it was going to break if I forced it. I sprayed it up and waited a day. Same thing, no change. So, I found a YouTube video of a guy using vise grips and a metal coat hanger to create a makeshift slide hammer. Repeated clamping onto the plug as tight as I could multiple times and using that trick to slowly force the swollen plug upward did the trick. It would come off after a couple strokes of the hammer, but it appeared I was making progress so I kept trying. I also alternated using a impact wrench to screw and unscrew on it a little thinking that might help loosen it. To anyone looking to do this, you have to make sure you’ve cleared the threads first of course. It was a little hard to tell if it had cleared but I figured it had just judging it against a new plug. Anyway.. it can be done... and maybe I got lucky but you have to be patient. Link below to the makeshift slide hammer.
