4.7 problems.... absolutely stumped. please help.

My neighbor has a 4.7 ram 1500 with some engine issues and me and my dad who are both mechanics are trying to do him a favor and help him out so he hopefully dosent have to take it to hendrick dodge to get it fixed. Only problem is were completely stumped... so the story goes like this.. he was driving when he noticed the temp gauge was pegged on hot, he pulled around to the back of the school he works at quickly and filled the radiator (which was empty) with water. It cools off and he heads home... a few miles down the road it does the exact same thing so he pulls off. he uses a rag to check the rad which still had water and so did the plastic tank. he waits for it to cool and continues home when suddenly the engine stops on him. he again pulls over and tries to start it back up but its locked... so its towed to our house and we start looking it over. no water pump leak, but small radiator leak. we turn the crank pulley with a breaker bar and its not seized so we jump start it.. it runs terribly its spits and sputters and absolutly will not idle unless you hold the rpms at about 2.5k, once you get it above 2.5 or so it revs great. so we starting thinking either head gasket or cracked head. possibly cracked block.. so we look and the oil is black not chocolatey.. no white smoke out of tail pipe (although he did put water in it so it would just be steam). we took all the plugs out and not a sign of water on any. so we assumed the running condition was caused by heat fouled plugs. we replace the plugs and same thing. runs a little better still very rough and will not idle. so here we are... stumped. what goes bad in these 4.7s that cause this kinda thing? please help i know therse gotta be one of you dodge techs out there that have heard of this or experienced this before

thanks,
ben

not sure if this helps? but i know there's a coolant bleeder where the radiator hose goes into the motor, my dads 4.7 overheated after we did the water pump and refilled the coolant and it was bc there was bubbles in the system after we opened the valve you could hear the air hiss out then we tightened it and refilled it and it was good to go. Like i said idk if that helps but it might good luck!

Thanks for the help! I'll remember that bleeder valve when I install the rad

Be aware though that these 4.7s DO NOT like to be overheated. Have heard of warped heads, etc...

Sounds like it needs heads to me

Sounds like having low water and then filling it up made a air block in the coolant system. Raising the front of the vehicle and letting it out would help.

Overheating may have led to the heads, gaskets, or block problems.

Welcome to RF.

Bigboytoys said:

Be aware though that these 4.7s DO NOT like to be overheated. Have heard of warped heads, etc...

Click to expand...

This ^^ and this:

HolyRamBatman said:

Sounds like having low water and then filling it up made a air block in the coolant system. Raising the front of the vehicle and letting it out would help.

Overheating may have led to the heads, gaskets, or block problems.

Welcome to RF.

Click to expand...

Sounds like when the rad was refilled, there was a trapped air pocket.

4.7's don't like overheating. I'd bet you an internet cookie one, or both, of the heads are warped.

Thanks for all the help. Were yet to pressurize the cylinders to check for head gasket/cracked heads. If they are warped will air still come up through the coolant system and bubble in the rad like the same for cracked heads or head gaskets?

I would believe so, as when the heads warp, they no longer seat flush on the top of the block, which will allow air to come in the the openings.

Head gaskets went, warped the heads, cracked the heads...

New motor...

Ask me how I know.

lots of head gasket issues with that motor. i agree with everything above.