ok first and foremost, i know that blowing white smoke usually means im leaking coolant into the combustion chamber. now my questions are as follows.

1) what is the most common cause of this (gaskets im assuming)

2) can i use ANY 2nd Gen 3.9L motor if the motor or heads are gone (getting another if this is case and using it as a donor)

and this all started cause the inline (upper rad hose) filler neck broke and i temp fixed it to limp it home.

im honestly praying its just gaskets.. i really am

 

is it white smoke just when you start it or is it the whole time you drive?

 

are you over heating or losing any fluids since I assume you've properly fixed the rad?

 

Wes, yes to both questions. But I don't think you've destroyed your engine.

You need to replace all the upper engine gaskets. This can be done with the engine still in the truck. Head gaskets, plenum gaskets, valley pan gasket, replace them all. If you've done engine work, this is something you can do yourself. If you haven't, you can buy some tools (a couple of torque wrenches, some sockets, and a Haynes manual) and learn to do it yourself.

How many miles? You might consider having the valves ground while the heads are off. & Replace that damned radiator neck!

Then replace the oil & filter, get the engine warm, and replace the oil and filter again (oil and whatever leftover coolant will emulsify, you want to drain it out completely.) Alternatively, pull the oil pan off and clean it with detergent or degreaser and put it back on.

Then take it out and run it about 25 miles. Get everything nice and warm. This will complete the 'drying out' of the engine. If the engine is okay, you'll know it. If it isn't, you'll limp home and start looking for another engine.

 

Klokworx, i dont dare run the motor more than 2 minutes.. it just dumps white smoke..

Blacktrim, i am in the process of fixing the rad hoses (rad itself is fine) as well as diagnosing the issue.

Brian, i have done gaskets once before, i rebult the truck over the winter. this is a new issue. and im PARYING i didnt crack the heads. the dakota has 236k ALL ORIGINAL

so i am contenplating a Hot Spare for my motor. but honestly what are the odds that i cracked the head?

it only ran badly for 5 miles (limped it to the parts store to attempt to fix) i stopped twice to let it cool down.

 

Well the good news is that the engine still used cast iron heads. If you had aluminum heads, you'd probably be toast--warped heads.

It doesn't sound like you got it hot enough to do any permanent damage--tho I'd probably throw a set of new rings in. And now we're getting to pull the engine time.

It's easy to predict what damage may have been done. You may have damaged a bearing, busted a piston ring or two, but probably you didn't crack a head.

At 236,000 miles, I wouldn't put any money into this engine. This engine has done its duty, time for some renewing. I'm in a less immediate, but similar situation. 230,000+ on an engine, and worry about reliability. I'm going through a used motor in my carport with the idea of replacing the old engine with a lower mileage one.

At this point, I think you need to consider your alternatives. A crate motor--get a good remanufactured engine and be done with it. Or, a good used engine--always kind of a crap shoot but saves loads of money. Or, rebuild your current motor--pistons & rings, bearings, a cam, & heads reconditioned. Or, sell the truck as a fixer upper for practically nothing and move on.

And a lot of it depends on the condition of the rest of the truck. Lot's of frame rust? Might be time to consider something else.

 

Brian, the truck was torn completely down and rebuilt from ground up over winter, frame blasted and power coated... aswell as most of the suspension componets. the motor was taken out and cleaned up as well as re-gasketed.. what i FAILED to do in the motor work was to go thru 3 heat cycles and re-check torque. so i really belive that was the cause. the heads do seem pitted a little (common with 3.9L heads) but not bad enough to cause a massive leak,

when i say the head bolts werent torque checked, i mean it, and when i went to remove the head bolts, 12/16 were loose and i didnt need to use a bar to loosen em.. on 4 the torque was right...

thats what makes me think the heads werent torqued right, but all 6 pistons were flooded, and bolts on both heads were loose. so i am really leaning towards the torque wasnt right and the overly hot coolant was able to find its way to where it did

 

You're saying that you had coolant in all the cylinders? That's a fairly catastrophic failure. I've never had a failure like that, and not re-torquing doesn't account for that kind of leakage--they don't duty cycle and re-torque new engines from the factory. Re-manufactured engines don't require re-torquing, either.

Come to think of it, I've never re-torqued a head and have never had that kind of failure. I can't even imagine what happened. It happened on both sides of the engine, man. Both head gaskets don't fail at once. It almost sounds like you had a water jacket failure in the plenum and the engine sucked in coolant through the intakes.

I can understand not wanting to dive in to a new engine project, I guess I'd be inclined to roll the dice myself if I were in you position.

A set of gaskets is fairly cheap. And probably a set of new head bolts. You could haul the heads to a machine shop for inspection, too. It doesn't sound like you overheated it, but my fear would be that the rapid cooling might have damaged your rings.

I guess I'd vacuum all the moisture out with a shop vac, change the oil, button her up, and cross my fingers. Worst that can happen is that you'll be out the time and the cost of the gaskets. And then you will know and can start planning your next move, whatever you decide to do.

 

I have to agree with Brian, I have blown head gaskets, warped heads, wrapped vehicles around trees, and rolled them along with seeing them in an accident as a fire fighter, I've never heard of coolant in both sides of the block or all cyls for that matter. you my friend are ****ed i'm sorry to say

 

I would have to agree with all the other comments here. I have done some bad things to engines over the years and never had what you describe happen.
Water in the engine, whether it's coolant, river water etc. is usually the end of an engine.
Cracked heads, valves, blocks, pistons, and I could go on. Not to mention what it does to the bearings.
IF it runs and sounds ok I would guess that it wouldn't last long before you are going to have to go back inside it.
You said the engine had just been rebuilt? Pull the engine and tear it back down and check EVERYTHING. Maybe it's salvageable, maybe it's not. But at least find out what the heck happened before it goes bad on the side of the road.
I'm hoping it isn't that bad for you, but it aint sounding good.
Good Luck and keep us posted