3406 fuel in oil / injector removal

3406 fuel in oil / injector removal

Posted in the Caterpillar Forum


Woodridge, IL

#1 Mar 21, 2010
hey guys i have a 91 international with a 3406B (3zj1) with 998000 miles.
its putting fuel in the oil.though im not exactly sure how much.(new project) i dyed the fuel and looked in the over head. after a minute or two it starts puddleing ontop of the head. i cant exactly see where it starts. the #4&5 cyl. are misfireing. and the puddle starts there but not from the jumper lines.

it blows a bit of black smoke at idle. leads me to belieave that the injedtors are the culprit. i was going to pull them to inspect the seals and bleed screws. if theres no luck on that have them tested.
any thoughts on that?

also is there an easy way to remove an injector without all cats special tools.(i dont think theese just pull out)?

Turin, Italy

#2 Mar 23, 2010
No clue about your leak, but here is a tip on a removal tool: We have 3408 TADI marine engines in our yacht. I think the injectors may be mounted in the same way on the 3406. The thread on the top of the injector is M14x1.5 and we just made a brass pipe with this thread in one end and a M8 thread in the other. Screw it on the injector and put some heavy nut or similar on a long M8 bolt in the other end to use as a sliding hammer. Tap lightly on the side of the pipe while pulling the weight along the bolt. Worked great for me!

Good luck!

Turin, Italy

#3 Mar 23, 2010
Oh! and don't forget to remove the lock nut holding the injectors
before trying to pull them out :-)

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