Overheating and heater bloing cold air

Some vehicles hve to bejacked up when bleed may have air in system still.Renaults few these vehicles can be hard to get air out sonetimes.I suggest you talk to your mechanic

engine running too hot.check coolant level, should be 50/50 antifreeze and water.replace thermostat and radiator pressure cap.check antifreeze level in the radiator,coolant level should be just below radiator cap, add coolant to overflow jug,should alway be at the full cold mark.empty coolant overflow jug will allow air be drawed in the coolant system causing overheating.if overheating happens when coming to a long stop.could have faulty engine coolant temperature sensor or bad coolant fan fuse or relay.

Raise the car front end as high as possible with a floor jack, fill the coolant tank to the top, run the engine until it reaches just short of overheating, shut it down and run water over the radiator, this will burp the air out. Repeat as needed. Don't let the coolant recovery tank run dry during procedure.

coolant leaking into engine probably blown head gaskets. More damage will occur the more you drive it. Unfortunate and expensive repair on a northstar.

Sounds that you are low on coolant so low that the coolant sensor is no longer immersed in it If the coolant sensor is prevented from working, due to low levels of coolant, then the engine radiator cooling fan will not be started and overheating will result. The gurgling you hear is due to air in the system. When the engine is cold remove the coolant reservoir cap. Set the interior heater to max temperature. Top up the reservoir to the maximum limit with water/antifreeze mix (2:1 is usual). Start the the engine. Be prepared to add more coolant mix as air is cleared from the system. When the top hose from the engine to the radiator gets warm give it plenty of squeezing to help shift any air pockets. The fan should also start at about this time. Make sure that the interior heater is blowing hot air. When the gurgling has stopped and no more coolant needs to be added to stay at the max level then replace the reservoir cap and secure it firmly. Allow the engine to reach running temperature. Check all hoses, junctions, gaskets water pump seal etc for any signs of leaks as it would be good to detect any cause for the previous loss of coolant.

I'm thinking your cooling system has air in it. If you have recently drained and refilled the radiator, then that is probably what's wrong. I'll be brief, and tell you how to get rid of the air. Put the heater control on hot, fan off. Remove radiator cap. Start engine, let it warm up. Watch the coolant level in the radiator, when the thermostat opens the coolant level will drop. Add antifreeze to bring it back up to full. It will drop again. Add more antifreeze. Continue to do this until the coolant level no longer drops and the coolant is flowing good. Put the radiator cap back on. and see if the heater is working better.

With a COLD engine, open up the radiator cap to see if you have enough coolant. If you are low, it may still be good enough to cool the motor, but will only be able to circulate coolant through the heater circuit with high revs. Do you have a temperature gauge or just a light? If the motor is overheating, you must be just about out of coolant as well.
If you share the cold with me in Canada, you MAY have a frozen radiator/heater if the coolant antifreeze wasn't strong enough for the winter. In that case you if you get in and drive the car it WILL likely overheat since the liquid coolant is solid or slush and can't move through the radiator to cool.
OR... maybe a cable for the heat/cool control is disconnected or you have lost vacuum control for fancier models... did you ever hear a "shhhh' when you moved the heater controls.?
Let's hope it's just low antifreeze... if you add some, make sure you maintain about a 50/50 mixture of antifreeze/water.
Hope this helps...
/denis from Canada

Start simple, check the coolant level, if it's too low, hot coolant won't reach the heater core, resulting in no heat. If the level drops further, the engine overheats. So check the level 1st, if it's ok, what does the engine temp gauge indicate? Is it running cold, normal, hot?

Did you make sure you filled the radiator up and got the overflow tank up to the correct level? Sometimes when you flush and drain the system and fill it back up air pockets can get trapped in the system. Start the jeep up with the radiator cap off and wait for the coolant to start flowing and when the air pockets make their way through they will escape and you can add more antifreeze.

Also, did you make sure you installed the thermostat so it is facing the right direction?

Good Luck

Many items need assessment. First what is THE COOLANT LEVEL enine running from cold start. IF LOW . Is there a coolant leak and where ? Lets say all of the previous check OK. ARE THE COOLING FANS OPERATING ? . They are , GREAT. Is it possible the cooling system ( i.e. radiator ) is clogged internally, or blocked exterior cooling fins of the radiator restricting cooling air. Hope this helps.