High Pressure Oil Rail Plug Wont Come Out

I have a pretty bad leak coming from the high pressure oil rail plug on the back of the head near the turbo. Its the plug that has a 1/2 inch hole in it. I have been trying for about a week to get this dam thing out and it seems to not want to budge. I have tried heat, penetrating oil 3/4 times a day to try and help it out, impacts and nothing is even considering budging the damp thing.

Is there a special trick to get this thing off with out totaling it and having to remover the head / motor?


Trying to get her finished up today, last thing it needs till its back on the road.

Thanks for the help!

Breaker bar with a pipe on the handle to extend it farther, assuming you can get it in there.

Back of the head, you are turning it in the proper direction to loosen it, correct. Easy to get mixed up when looking at it from the wrong direction.

At that point id be afraid to strip it shes already pretty tender. I have already used a 3ft bar to try and get it and its not moving at all. This aint my first rodeo but this think is kicking my arse. Can I literally weld it or is there a high temp sealer I can put on to till I have time to pull the motor? This truck has been the biggest pain I have ever worked on.

I id assume Im turning it the right way im turning it down toward the turbo

If you are working on the passenger side head, that would be correct.

Sorry, not trying to be a smart a$$. Just seen it happen way to many times on these forums. I would not trust any compound to do the trick, all that will do is make it harder to fix later. Lots of pressure in the line.

No offence taken, I have and im sure we all have tried turning something the wrong way. I just tried a larger bar with blocks to support the ratchet and ratchet straps to hold it in to it wouldnt strip and reefed on it for all its worth and still not moving and the hole is about toast. I swear some one welded this thing in.

So thats that. Not sure what will take it out now I dont have a good hole to use. Might be time to buy a 6.7l

I think once I get done haying Im going to try to weld a large nut on it and cut a hole in the fire wall so I can get right at it and crank on it.

Wait, so you rounded out a 1/2" square hole?

gwunter said:

Wait, so you rounded out a 1/2" square hole?

Click to expand...

I was literally just getting that same plug out, except my motor is on a stand. I almost stripped mine out as well, because the ratchet does not go all the way into the plug. That was also the tightest one for me, I ended up using a five pound Sledge on the breaker bar to get mine to come loose, seems like striking it is better than just torque.

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I swear pulling the motor is easier than doing just about anything in frame on this engine.

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gwunter said:

Wait, so you rounded out a 1/2" square hole?

Click to expand...

Yeah the square 1/2 hole is now a round 1/2" hole. I think I would have had the motor out and back in if I had just started that way. Ill see what I can do with the welder.

Just know that when you put that much heat on it, you will wreck the oring

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Air hammer it carefully out, use a long chisel bit and get it turning, then you should be able to spin it out.

Its like a final drive plug on a dozer or excavator if you will. If only there were room to smack them with a hammer a few good times, they would break right loose, but theres no way to do that on a rear plug in frame.

I also think before i deal with welding it (I do have a new seal and end cap) I might try to cut a small hole in the firewall to get a pry bar in and hit it with a hammer. I assume its the threadlocker that is stopping it from moving and not the torque, a swift hit or 2 might break it free?

Thanks every one for the replies, this has but a fun task haha!

The heat will take care of thread locker

Thats the weird thing though the heat did nothing, and I had it pretty damn hot, Idk if it wasnt hot enough but like I have to walk away for a few hours after the heat because she was so toasty

Did you try to remove the plug while it was hot?

Yeah I tried getting the plug out right after I stopped with the heat, the had to stop working on it after it wouldnt move cause it was so hot

Something isn't right. Should be that hard to remove.