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Discussion Starter #1 (Edited)
4.7 '99 wj + radiator failure +overheated+driven(retarded i know but it was 2 miles from home) +overheated + battery died (related/unrealated??) replaced radiator& battery = tries to turns over but won't start

-throws no codes
-changed out spark plugs
-oil changed no chocolate milk.
-there was oil in the airbox/ tb(blown intake gasket?)

just trying to eliminate things,
i hear crank/cam position sensor can have similar symptoms but what are the chances of going bad after an overheat?? anything else i should check before i start pricing heads and long blocks?
 

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Discussion Starter #3
what makes it worse is my buddy had aaa with somethin like 300 tow miles... So based on the results of the compression test how do i distingish between
1) blown head gasket
2)warped heads
3) cracked block


Sorry if im askin dumb questions . I do appreciate the help
 

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Diesel Mechanic
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leakdown test would help diaging cracked/warped heads. blown head gasket could be determined by pressurizing the cooling system. cracked block would more then likely be noticable.

you more then likely ruined some of the internals by overheating it. in the long run may just be easier to find a good running junkyard motor to be honest.
 

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So based on the results of the compression test how do i distingish between
1) blown head gasket
2)warped heads
3) cracked block


Sorry if im askin dumb questions . I do appreciate the help

If you really wanna dig into it once you find the low cylinder/cylinders you can do a leakage test and see where the compression is going to but it really is kind of useless being that the heads are coming off anyway. Once the heads are off you will have the checked for flatness and also pressure checked tio make sure that the valves are ok. If you have any cylinder damage you will see it on the cylinder walls.

How many miles on the motor
 

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Discussion Starter #6
the motor has about 123k on it. based on the work involved to get the heads off , probability that something may be damaged and the fact i have a lot more free time than know how, would you guys agree with dakota99? am i just better off buying a salvage long block instead of attempting to tear down the engine?
 

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I am going through the same thing as you. Water pump failure, overheat, ets.

I decided to pull the heads. I have a different thread for it.
http://www.dakota-durango.com/forum/showthread.php?t=106917

It is hard to diagnose warping without having the heads off. A leakdown test will not really distinguish between a blown gasket and a warped head. (because the gasket will probably be blown in addition to any warp.)
I just checked mine for flatness and I will need a replacement head. I have 0.007 across the head at the two bolts between cylinders 1 and 3..
 

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DrPepper
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If it's not cracked...

why wouldn't you just have it milled flat? The block is probably not bent, a head milling and freshen the valves and your back in business. :huh:
 

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why wouldn't you just have it milled flat? The block is probably not bent, a head milling and freshen the valves and your back in business. :huh:
On mine the block looks fine. I will take the head to the machine shop for a look on Monday. Dodge OEM Spec for flatness on the Cylinder head is 0.0508 mm (0.002") I have between 0.007 and 0.008 of warp (see pic in the other thread) It will come down to value for money at this point whether to try to save it or just put a reman on there.
http://www.dakota-durango.com/forum/showthread.php?t=107095


As for the original poster:
Does the engine turn freely?
Did the oil get cooked when it overheated?
Because the block is cast Iron, it is probably fine.

Do a compression test... if only to determine if both banks are bad or just 1 bank. Even with that knowledge, you can have an idea how much you will spend in parts if you decide to fix it.
Granted, in my case this is the first 4.7 I have been in, but the amount of work to pull both heads is only a small amount more than pulling just one head.
Most of the junk on top and the exhaust manifolds would have to be removed to do a swap anyway. It really depends on if you have the time/tools.

Now, if you found a lower mileage engine for under $1000, consider the swap :)

..... my 0.02... :)
Regards,
Kevin
 
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