hey ya'll
 

I'm Patrick everyone knows me as paterrack and I've been on here for a little while now and just figuring it out some! Maybe someone can help me out cause I'm stumped with my 2000 Dakota with a 4.7 in it! It keeps over heating on me an I've recently had the motor rebuilt this past month, an it started shortly after that I haven't even gotten 500 miles on this $1600.00 piece of rebuilt power and i've done replace the radiator waterpump thermostat bled the air out the lines several times flushed the entire coolant system an it's still running hot on me, it will run out just fine for around 20 + miles then get hot turn they're heater on to kick it back down an it blows cool air then a couple minutes later it'll be hot an running at normal temp then if I stop for a short period of time it starts again what do I do??

Welcome to DF

I will move you post to the 2nd Gen Datokta section.

Idk off the top of me head but i had a neon once that kept reading as overheating but all it was was a bad ground that had to be fixed i think thats a rare issue but if anything else comes to mind i will let you know

Try the easy things first.

This is right out of the 2000 manual on bleeding the 4.7. It's a piece of cake and works:

REFILLING 4.7L ENGINE
CAUTION: Failure to follow the procedure outlined below, can result in engine overheating conditions and severe damage to engine.
(1) Tighten the radiator draincock and the cylinder block drain plug(s) (if removed).
(2) Fill system using a 50/50 mixture of ethylene glycol antifreeze and low mineral content water.
(3) Fill coolant reservoir to FULL mark.
(4) Install radiator cap and reservoir cap.
(5) Start engine and run at 3000 RPM for 10 seconds.
(6) Shut engine off.
(7) Remove radiator cap.
(8) Fill radiator to full level.
(9) Install the radiator cap.

You have air in the system if it's not flowing water through the heater core. It could also be a bad head gasket.

What thermostat did you put in? Did it have the bleed hole?

Try this first.

Take it back
 

If I just spent $1,600 for a rebuilt engine I would take it back and have them look at it just to cover my ass for the warrantee. I should think a complete rebuilt engine should cover the cooling system they should have checked that at install and suggested any needed changes or replacements.

Cover your butt get it to them

Or was it done by a friend?

I built custom VW bug almost racing engines back in the 70's and early 80's out of my home garage and always made damn sure it was running perfect in every way before I gave it to my customers/friends. When anything came up I looked at it for free I built it and it was my reputation so anything strange like overheating I fixed. Granted the VW was air cooled/oil cooled.

One way to check is take a laser temp guage and shoot the water neck it should be what your t-stat temp is.then shoot a couple spots along each cyl bank and look for the hot zone. a rebuilt engine will run a bit hotter due to the fricton from not being worn in. take back to the shop and have them look at it. could be something as simple as a bad ground or sensor.
Time to break out the tools and have a looké

If the heater is intermittently blowing hot air then it's more than instrumentation.

Houston, we have a problem.

my shot at it
 

I think you said it has a new water pump on it if so then I would say it’s either the radiator is not doing its job or your fan is not doing its job so either you need more water flow through the rad/cooling ability or more air flow through the rad.

I say this because you say if you use the heater to help cool it and that works but at a stop it starts over heating again. It just needs one or the other fixed as stated above

Im thinking its air flow if it starts overheating at a stop.