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New Guy here with 3406C

5K views 10 replies 5 participants last post by  ynot 
#1 ·
Hey guys. Glad to be on here, and ready to learn!! I bought a truck 7 months ago, along with a dump trailer to start my own business. I'd eventually like to buy a lowbed too, but I need to start re-saving money once I get started. Anyhow, the truck is a '93 Pete 379 long hood with 443K on the clock. It's got a 425 3406C under the hood, mated to an RTO15715 (love the tranny). The exhaust manifold leaks at two cylinders, and has what looks to be fuel or oil with soot coming out another. These issues have developed within the past 6 months. The truck is not registered yet. I planned on doing it this week, but my radiator started leaking from the top (rot) so that has to come first. This engine had the stupid cover on both sides of the block, so it's pretty scaly (where I think the exhaust leak came from). Where exactly should I start? What else should I look for, be aware of with this engine? It runs/idles fine with minimal blow-by and good oil pressure. The arrangement number is 6I347 if that helps. Educate me! (wish me luck too..)
 
#2 ·
Sounds to me like you have an engine that was not maitained very well. Cooling problems on a diesel very often indicate more serious issues on the inside. If the coolant has not been maintained with proper additives it could have damaged the cylinder liners, clogged up the oil cooler, etc. Maybe a good first step would be to pull the exhaust manifold to fix the exhaust leaks. To do that you should remove the temperature regulator housing. That will give you another look inside some of the coolant passage area to see how bad it is inside.

There is always going to be soot at an exhaust leak. However, if there is oil or fuel leaking out also, it indicates a possible injector problem or worse, rings or valve guides.

I don't want to sound negative but, given the problems you have found you might be spending some money on this one.
 
#3 ·
Hello DDT3406: Welcome to the forum. Yep, there are some(a few) guys in here that really know truck stuff.They will be able to help you with anything truck related (and maybe a few other things):D.
Do a search and you will be able to find posts that will answer most questions.
Best of luck with your truck...:happymugs
 
#4 ·
Drop in a new set of nozzles and run the overhead after fixing the exhaust leak. Test water pump pressure at the closest heater hose to the oil cooler inlet. Then buy 1) 4N641 gasket, 3) 109-0077 orings and 2) 109-0076 orings, yank the oil cooler and blow out both sides with a Hotsy. Clean it up and throw it back together, then post before and after pressure specs. We'll go from there ;) . Welcome aboard and Happy New Year
 
#6 ·
How much does Cat get for new nozzles? What exactly will new nozzles do; eliminate the oil I have coming out the exhaust gasket? I'm no mechanic unfortunately. The most I've really done to this engine was rebuild the fan clutch after a friend helped me pull it out. I did change the fuel/oil filters, and will be putting in fresh Cat coolant when I get a new radiator. I do know the reason for the exhaust leak is rust on the block flaking and pushing the manifold away from the block. Would I be better off getting a new exhaust manifold? I'm not having cooling issues if that helps. The radiator just weeps at the top after the truck is shut off (pressure in the rad./surge tank) due to excessive rust. I believe it's the original radiator.
 
#7 ·
First thing I would do is have or do a valve set, then if you have exhaust gasket leaks fix them , if the truck has sat around and idled quite a bit it will eventually slobber and look like leaks. if the nozzles are not cracking at the right pressure it will slobber.nozzles will cost about $200.00 each , if you change 1 change em all. If the truck had green antifreeze put green back in it or you will be doing liner o rings in the not to distant future.
what is the engine serial prefex?? 3ZJ ?? or what
 
#10 ·
The CAT longlife is chemically more aggressive and tends to eat old O-Rings
Tony (Ynot) posted the exact reason a few months back if you search his post you should find it
 
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