What is this plug on 7.3L?

[huntnphool]

I asked my lead diesel tech what he thought. He’s been a Ford diesel tech for 20 years and works on anything from the old 7.3’s to the new 6.7’s.  Obviously tough to diagnose stuff over the internet.

  Ford service advisor at one of the busiest dealerships in the state, with a expert 7.3 mechanic giving his best guess, and yet internet experts know more than both!

 Can’t wait to see how this turns out! My guess is the OP figures out that the engine is toast, Jackelope and the mechanic were correct, and the thread disappears without acknowledgement..  

[syoungs]

I asked my lead diesel tech what he thought. He’s been a Ford diesel tech for 20 years and works on anything from the old 7.3’s to the new 6.7’s.  Obviously tough to diagnose stuff over the internet.

  Ford service advisor at one of the busiest dealerships in the state, with a expert 7.3 mechanic giving his best guess, and yet internet experts know more than both!

 Can’t wait to see how this turns out! My guess is the OP figures out that the engine is toast, Jackelope and the mechanic were correct, and the thread disappears without acknowledgement..  

My guess is the aftermarket freeze plug I installed in that motor years ago has fatigued due to vibration, and either couldn't take the typical amount of blow by that a 7.3 has, or the turbo seals are shot and leaking boost down the oil galleys causing it to blow out. Ive been down the burned 7.3 piston route w few times, and the blow by is amazing. no way that the simple cap test would have passed imo.

Like jackelope said though, tough to diagnose over the internet.

[jackelope]

Definitely 200% not trying to tell you what’s wrong with it. Just saying I wouldn’t use epoxy or loctite or bust out the Miller to reinstall it. Get a new one and put it in the way it’s supposed to be installed. Monitor it.
Also it’s interesting to do the oil filler cap test with a ping pong ball rather than the oil filler cap. You can see a lot more.

[ridgefire]

I put a real small amount of blue threadlocker on the plug yesterday and took it forva drive last night and it did not pop out. I figured with the amount I put on it and it being a smooth surface it would easily pop out if there was any pressure in there. I will try a ping pong ball tonight. I am starting to think the plug was just old and time for replacement. I hope so anyways.

[deerlick]

I asked my lead diesel tech what he thought. He’s been a Ford diesel tech for 20 years and works on anything from the old 7.3’s to the new 6.7’s.  Obviously tough to diagnose stuff over the internet.

  Ford service advisor at one of the busiest dealerships in the state, with a expert 7.3 mechanic giving his best guess, and yet internet experts know more than both!

 Can’t wait to see how this turns out! My guess is the OP figures out that the engine is toast, Jackelope and the mechanic were correct, and the thread disappears without acknowledgement..  

clearly service advisors know everything, just ask mine, lol.

[syoungs]

I put a real small amount of blue threadlocker on the plug yesterday and took it forva drive last night and it did not pop out. I figured with the amount I put on it and it being a smooth surface it would easily pop out if there was any pressure in there. I will try a ping pong ball tonight. I am starting to think the plug was just old and time for replacement. I hope so anyways.

If your going to replace it with another plug, maybe contact ford or international to try and buy their version, instead of the stainless freeze plug I used. That stainless could have fatigued for some reason, or ford may actually use some sort of retaining compound when those plugs are installed from the factory.

[dyhardhuntr]

I asked my lead diesel tech what he thought. He’s been a Ford diesel tech for 20 years and works on anything from the old 7.3’s to the new 6.7’s.  Obviously tough to diagnose stuff over the internet.

  Ford service advisor at one of the busiest dealerships in the state, with a expert 7.3 mechanic giving his best guess, and yet internet experts know more than both!

 Can’t wait to see how this turns out! My guess is the OP figures out that the engine is toast, Jackelope and the mechanic were correct, and the thread disappears without acknowledgement..  

I’ve been a diesel tech for 20+ years and seen ALOT of things. I can tell you there will always be something out there a guy hasn’t seen. You just have to use the skills you have acquired throughout your career to diagnose. Anyone that has been in the field knows that diagnosing over the phone or internet is extremely tough. In my opinion the OP needs to find the root cause of why the plug came out. If the plug has been out from a previous repair and was reused that’s definitely an eyebrow raiser. The plug has already been compromised. Those plugs are made to be slightly bigger than the hole diameter. If someone had it out already the plug is at the same diameter as the hole. It’s not going to stay in place. If it had burned a piston you would be getting major blowby plus raw fuel out of the tail pipe and or fuel in the oil from Unburnt fuel plus a miss. Unless it’s a small hole. I agree with deerlick. Excessive crankcase psi will blow a seal long before a plug.


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[ridgefire]

I started the truck and put ping pong ball on the oil fill tube and it moved a little bit and may have been slightly hovering but it did not blow off on in the minute or two I had it on it. I hope that's a good sign.

[LDennis24]

There seems to be a back story of someone selling this rig to someone on here and someone did some work on something somewhere...

Stainless steel stretches and does become fatigued. I would buy original Motorcraft.

[ridgefire]

Yeah, I bought it a few years back off this sight.

[syoungs]

yep. I sold the truck after replacing the engine and transmission.

[LDennis24]

What brand of CPS sensor is in it? Any other aftermarket sensors installed before you sold it? What else did you have to do to the engine you installed before selling it?

[syoungs]

I'm pretty sure it went with a oem cps, but its been a few years so I'm not 100% sure. Other sensors were oem.
Engine got ne injector cups, injectors were resealed, new water pump, oil pump, rebuilt the oil cooler, rebuilt turbo... Basically if a part could be rebuilt or resealed, it was. Went together with new valve cover harnesses, new glow plugs etc...

[ridgefire]

It has a OEM CPS in it. I drove the truck from Monroe to Reiter Ponds today and the plug did not come out and the truck ran great. I bought a new plug today and now got to figure out how to get the old one out. I could not imagine the blue threadlock will hold to much.

[LDennis24]

Well good luck! Hopefully it's nothing but a loose plug. I was wondering if someone had changed a bunch of stuff and you changed it back syoungs. That's why I was curious about the sensors. Some guys just buy a bunch of garbage and throw it on the motor and think it's gonna travel thru time.