My 1996 dakota ran hot blew the top off the radiator. i replaced it now when it starts it will not idle and runs rough

There is a tap or valve on the heater or hose that controls the hot water to the heater radiator, make sure this is working and not closed or broken.

I had a similar experience. Finally the car started overheating. Turned out the thermostat went bad and the radiator blew a leak. Had those replaced. Runs great.

Could be a blown head gasket. You might also need to "burp" the system. When the vehicle is completely cooled down, try taking the radiator cap off, topping off fluid, and start the engine. That should help get air out. If it starts bubbling and shooting coolant out, something is wrong. You could also try running without the thermostat or just go ahead and replace it. They aren't usually expensive.

this could be a number of problems , firstly with engine running remove radiator cap see if large bubbles of air appear, blown head gasket. second depending how long engine is running before temp rises to overheating, thermostat. third, O2 sensor could be damaged this will cause rough running and slight increase in engine temp.(unlikely if idles well) fourthly damaged valves (inlet/exhaust)

I would check to make sure the radiator is full and the overflow tank is filled to the proper level. It doesn't have to be very low for these cars to stop blowing heat.

on your discription,i would say someone has not replaced a vacum pipe under the bonnet,or placed the wrong vacum pipe on the wrong pipe if you know what i mean,the vacum pipes run around the engine small pipes if you pull one of you will hear a sucking noise or if you spit on your finger you should feel it ****.when you say it blew brake line what do you mean ,please tell me excatly what happened because this realy baffles me,please come back to me on this problem .adrian,,,,

could be idle stop sensor.mine does the same,..it should be under the manifold cover,..check w/ dealership autozone may be able to run scan. There are three sensors the above,.and the oxygen sensor and the maf sensor.It should stop Idle hunting when in drive,.due to the other two override it when signals dont match.. Have it scanned. I am in same boat,.Mine ran hot but didnt steam til december 1st I blew the head to heater hose 80 bucks to repair but then I still ran hot and steamed,.today I replaced the radiator,Fins were completely shot..lost tranie fluid due to a transmission coolant fitting breaking,.put it together ran to autozone and it's over heating again. So I have to think replace temperature switch,thermostate(Again) .Check to see if it looks like there is a fine spray of fluid after you shut it of. Maybe a small leak in top hose. When it goes,.you'll end up like me w/o heat due to plugged heater core. But the Idle stop sensor is usually the culprit to idle hunting. It may just be lose rather than faulty.Prices I have seen ran from 95 to 295 bucks. Good luck!! Erin

Sounds like maybe they left something unhooked or accidentally knocked something off. Personally I'd go back & explain, as they know what areas they worked on , and may be able to find it faster.

head gaskets

First place I'd look is at the thermostat. However, if the hose did not rupture in a normal manner and blew apart, I'd also suspect that you may have a blown head gasket. In that case, compression is entering the cooling system which is not designed to handle such high pressures, therefore causing the hose to explode). This will also result in rough running you observed.