I have been having some issues with my 93 7.3 non turbo not wanting to run some times. I think I have all of the issues fixed except for one, when my truck is running you can see fuel and air bubbles leaking out around 2 of the glow plugs. What would have caused this and how do I fix it?? I don't know if I should drive it our not until I get it fixed, don't want to damage my engine. Thanks

 

I have seen this issue with spark plugs and fuel injectors that were not properly sealed. Most of what I have seen appeared to be due to improper tightening. These times the item just required tightening after the sealing surfaces were checked for debris and abnormalities. We always replaced the sealing ring/washer/gasket in these cases.

Obviously, you are losing compression. From here, I do not think it is enough loss of compression to cause any running issues.

I would remove the glow plugs and inspect them. There is minimal clearances in the GP head openings that excessive movement or vibration could end up damaging a GP and your engine in the end.

Good luck. Keep us posted.

 

My old truck had return line caps leaking fuel, which would pool around the GPs. I also had one GP that wasn't sealing well, which caused bubbling...

 

The gps are pipe thread IE tapered thread sounds like they are just loose. I would try tightening them and yes the return caps are probably leaking.

 

The glow plugs are actually straight thread, the end of the body is angled so it turns into a compression fitting. just fyi

 

I had the same thing happen. Fix your return lines and tighten the GP's. I use anti-seize on the threads I think it acts kind of like pipe dope I haven't had it leak when I've used it.

Does any one know the proper torque for the GPs?

 

12ft-lbs for glow plugs, also the anti-seize is a good idea, also good to put on the threads of the injectors

 

Thanks for the help but I did some research and figured out what the bubbling around my GP's was and they were all tight. But I did read that if the threads and the seat were not cleaned properly before install of GP's that they wouldn't seal if there was just the tiniest amount of dirt on the seat where it seals. I also loosend all of them and retorqued them to 12lbs. to make sure they were right, but they still leaked. And when I loosend them I couldn't turn them by hand so that tells me that there is lots of crap and prob carbon where its not suppose to be so I'm gonna get a new set of ZD9's to put in it and clean each GP hole thuroghly and carefuly. I have a couple bad GP's any ways, my relay started clicking a couple weeks ago. I watched a good video from Mercedes on how to properly ream them so gonna do that also cause the logging co. that had this truck before me didn't treat her very good. The fuel was left from where my return caps were leaking, I bought a return line kit on ebay for $24 and it was junk and started leaking again 2 days after I put it on so I bought a kit from the dealer and put it on and NO LEAKS NOW!! So don't buy the kit on ebay for $24 it is junk!!!!!! I hope it doesn't have AUTOLITES in it I have read they are horrible to take out once they have burnt up. How can I tell if they are autolites when i remove them? Will it be marked on the GP? I also noticed while I was poking around in there that I had 8 loose valve cover bolts and quite an oil leak, I hope tighting them fixed the leak. Most importantly will it kill the motor if I drive it with the GP's leaking? It will be a couple days before I can change the GP's. I also figured out why it kept dieing on me, evidently the cone of failure had been replaced a couple times in the front tank and they didn't remove all the rubber peaces from the tank, I pulled the fuel lines loose and the supply line on the sending unit was packed full of rubber peaces. I put a new cone of failure in the rear tank and blew all the lines out good and it is running now, just gonna use the rear tank until I get the front one cleaned.

 

You wont kill the motor driving it a few days with leaking glow plugs, worst case is the leaking cylinder wont make enough pressure to fire, but for a few days, just run it.

As for Autolite gps, there not always swollen and unable to be removed, they have been known to swell but its not like everyone of them will swell.
This one I pulled from my truck the other weekend after we had a -30 cold snap, not even the slightest hint of swelling, though there is a bit of corrosion on the end but the previous owner could of been giving it some crack



They label them at the bottom of the body for all the plugs I've seen, also the insulator were the wire connects is different colors depending on brand from what I've seen.

 

It had 3 autolite's and 5 bura's in it and it stoped clicking after I changed them so I guess I'm good to go for now!! Thanks