4.7L Overheating

[Hupomeno]

Water pump changed, new thermostat, blew out heater core lines, fanclutch good, not head gasket leak. Truck ran perfectly normal temperature and plenty of heat in cabin for two weeks after changing thermostat and flushing heater core then it started overheating again! Temperature goes to hot and heater blows cold idling or below 2000 rpm. When I get on it over 2000 rpm or at 70-80 mph heater blows hot and engine temp normal. Do I still have restrictions somewhere in system, radiator blockage? I read that 4.7L are known for this. And yes we bled air out of radiator and there are no coolant leaks at all. Did head gasket check, oil normal color, did radiator check, no smoke, plenty of power. Stumped, what can it be??? Please help...

 

[misfit77]

In all my previous cars, the heater core is fed from the high pressure side of the water pump. Not from the radiator.
I haven't a clue if Ram followed the convention.

I don't suggest it but I had a mustang that was clogged at the heater core. I ended up back flushing using the sprayer from a car wash.

Sent from my moto g(6) using Tapatalk

 

[Tach_tech]

What test did you do for the head gasket? Cracked valve seats are fairly common on the 4.7 and they can cause really weird intermittent overheating conditions. Does the system build up pressure really fast?

 

[bubba5xx]

???

 

[Hupomeno]

What test did you do for the head gasket? Cracked valve seats are fairly common on the 4.7 and they can cause really weird intermittent overheating conditions. Does the system build up pressure really fast?

 

[Hupomeno]

Yep, building up a lot of pressure, we did dye test and it blew bubbles and dye turned yellow in just a few minutes. Definitely head gasket issue. Not sure what I'm going to do now, he said head gasket repair for this 4.7L will be $2500 or more because of all the labor to get to heads. I just googled it and it said $700-900. Is he exaggerating or does it really cost that much?

 

[MADDOG]

He's blowing smoke...no way it should cost that much.

 

[Hupomeno]

He thinks labor will be 20-25 hrs, should be more like 15-20. I'm thinking maybe $1000-1500, going to call several local shops tomorrow for estimates.

 

[Tach_tech]

Labour is not 20-25hrs lol. I’m not at my computer to check, but it’s probably around 15. That might be his “ I don’t wanna do this job” price. Good chance those heads are cracked too, so that’ll add to the cost as well.

 

[Hupomeno]

He's busy with his regular job and really doesn't want to do it right now. And he did say to make sure to get heads checked and that would be more $$$ as well, especially if warped.

 

[huntergreen]

He's busy with his regular job and really doesn't want to do it right now. And he did say to make sure to get heads checked and that would be more $$$ as well, especially if warped.

Just curious, how many !Iles on your engine ?

 

[Hupomeno]

123185

 

[Arth]

123185

Wow that sucks. Did this all stem from overheating one time? I've got the 3.7 in my Jeep and I was told never let it over heat or I'll risk having issues just like this.

 

[Hupomeno]

Water pump failure a year ago must have been root cause, overheating on highway. Also fanclutch bad...

 

[Arth]

Water pump failure a year ago must have been root cause, overheating on highway. Also fanclutch bad...

Yeah that's what I figured. Over heat one time and you're done.