Identify this injector

And..... there went the head gasket. Jody said I should be getting almost 40lbs of boost, I checked for leaks, tightened a few minor leaks at the boots, up pipes were clean, and went to relog. Hit 30psi and heard the gasket go. Guess I should have been watching the damn back pressure.


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You sure???? Maybe you blew a boot or an intake. The HG on a 7.3 is pretty hard to blow.

What symptoms do you have?

Billy T.
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Giant white cloud, reached 230f oil temp as I nursed it into the driveway and coolant sprayed all over the underside of the hood.


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Sounds like you may have blown the radiator.

I would pressure test the system before tearing the motor apart.

I'll pressure test everything but the white cloud was coming out of the tailpipe all the way back to my house.


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Or an injector might have not been installed correct or cracked an injector cup on install. I would diagnosis the issue before tearing apart the motor.

Billy T.
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Pull the intake and check play on the turbo shaft....

Just rebuilt turbo with a new wheel


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The coolant is black. Injector cup?




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Or oil cooler. Oil pressure is higher than coolant pressure.

Billy T.
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Pull the injectors and add shop air to the degas bottle to around 15 psi or so (have a helper wrap a rag around a blow gun and press tight to the bottle opening) and watch in each injector bore. If you don't see any coolant or hear any hissing then it's not the sleeves.

But I can't believe a head gasket would blow at 30 psi. I had my stock head bolts/gaskets hold several runs over 50 psi.

Ran a compression test. All but one cylinder was between 300-320 with a cheapy harbor freight gauge. Oil pan level is way up and degas bottle is empty. Pulled the injector from the cylinder with zero compression and it looked like the cup was full of coolant. Could have just been the oil/coolant mix from pulling the injector since I didnt drain the rails. Cracked cup pour coolant into the pan?


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Shop air in the degas comes pouring out the injector open that had no compression


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Pulled the cup. No cracks and was in the head quite firmly.


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Cracked block, cracked head or blown head gasket. Cracked head ive never saw before on a 7.3 but ive heard they can crack inside. Cracked cylinder wall.

I just dealt with the cracked cup problem and fuel in the coolant no oil in the coolant.

that looks like a Cat part number

While I wait on Riffraff to get my studs here, curiosity got the better of me. I disassembled one of the injectors to take some measurements. The piston is 29.7 or so, plunger is 7mm, and the nozzle is marked with 7-16 F6. I'm not sure what the nozzle markings are but I'm pretty sure the short piston and larger plunger makes a 238? hybrid.


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