We bled coolent at Thermostat and heard air leaking out to the point were it would not take any more coolant. Should we leave the radiator cap off for the 30 minutes ? The right fan is working, I believe the left fan is for AC.

Most likely air in the system. If the system is not properly bled, air will be trapped in the lowest point of the coolant system and can get trapped in the heater core. You need to run the engine with the radiator cap off till all the air is pushed out of the cooling system.

Turn the heat control to max and remove radiator cap - add coolant as much as possible. Make sure overflow container is filled to correct level - then Start car and run - after the thermostat opens water level may go down some - keep adding coolant till it is totally full. Turn engine off and put radiator cap back on tight.

add coolant let it run til the thermostat opens to see where the level is at if you need to add more or not

hello my8,
First confirm that the engine is actually overheating - steam, no heat to the interior etc. Sometimes a temperature sensor will fail and give a misleading 'overheat' reading on gauge. For that matter sometimes the gauge can fail and give the same misleading reading. Check that the cooling fan comes on when the engine temperature starts to rise above 'normal'. If not check (in order) fan fuse, fan relay, fan sensor, fan. Real overheating is caused by a lack of coolant AND/OR lack of coolant flow. Modern cooling systems are 'closed'. In other words there should be little or no loss of coolant. If the level is significantly low you have a leak....either external or internal. With the coolant topped up to the correct level and the radiator cap on, run the engine and look for visible leaks...hoses, valves, radiator etc. Internal leaks, eg. head gasket will usually be accompanied by white exhaust smoke (steam), hard starting, rough running and bubbles in the expansion tank. Sometimes, though NOT always, you will fiand the engine oil has a milky look and/or engine oil will be mixed in with the coolant.

Lack of coolant flow can be caused by anything in the system that causes an obstruction......in order of common occurance......thermostat stuck closed, radiator blockage, heater core blockage, water pump failure. One last point. because of design considerations many vehicles have the radiator mounted at a different level than the uppermost coolant passages in the engine thus trapping air in the coolant passages. In short the system must be bled of air in order to properly fill with coolant. Such systems will incorporate bleed screws usually in either the top/side of the radiator, the top hose, the thermostat housing and sometimes in all of these points. To bleed out the air do NOT run the engine as you fill the radiator. Instead, open all bleed screws. As you fill the radiator coolant will run out of one or more bleed points. Close this bleed point(s). Continue to fill until coolant escapes from the next bleed point then close that one. Proceed until coolant has escaped from ALL bleed points then continue to fill to the correct level. The expansion tank will have minimum and maximum level markings. Fill only to the minimum level mark with the engine cold.

hope helpful,
greetings

Hi,
If you are not seeing any leaks, most likely air in the coolant system, improper/weak coolant mixture, bad radiator cap, bad thermostat. Sounds more like the air and/or weak coolant to me.
Mike

Assuming that none of the Electrical/Electronic controls were disturbed when changing the Thermostat it seems to me that you have an "Air Lock" within the heater. One must purge all the air out of the cooling system as close to the highest point as possible after the system has been partially or fully drained. Most of the time one will find small BRASS Bleeder Valves located somewhere near the highest point. Open each one while the system is pressurized and let Air escape until some Coolant escapes. Sometimes it may be necessary to loosen a Heater Hose and bleed the air at that point. Remember that the system MUST BE PRESSURIZED to accomplish the Bleeding of Air. Many auto parts stores sell hand pumps with a pressure gauge for this purpose and leak testing. These pumps typically replace the Radiator Pressure Cap temporarily. The system does not have to be at normal operating temperature to bleed the air out. Once the Air has been bled you will have to refill the radiator to normal full and make sure that the Coolant Recovery Tank level is also brought up to recommended level. A quick check is to remove the Radiator Pressure Cap, Start the Engine, Rev the engine suddenly (A short Jab) and see if the coolant level falls rapidly in the radiator. If it does it is definitely an AIR LOCK situation.

Fastest Robe

If it is leaking out of the radiator cap, then that means you need a new radiator cap. Your cooling system in your car is a sealed system. Sounds like your radiator cap is not sealing properly and when the cooling system is not longer sealed then the temperatures cause the coolant to boil whereas coolant not subject to the atmosphere does not boil. Start there.

Good Luck

Assuming proper fluid level your thermostat sounds like it may be stuck closed (or nearly closed)
If the radiator has little or no heat to it when your engine gets warm this is probably the case.

I hope this helps,
Tom

there is a coolant cap on the overflow bottle check it for seal
i'd just replace it
also if you put the new thermostat in backward the overheating would be significant

Sounds like you might have an air pocket in the cooling system. This can develop, usually after a service, where the cooling system has to be opened to replace a water pump, thermostat, or other reason. When refilled, the air displaced by coolant has to go somewhere. In many cases, youll find that air is trapped in the highest place it can go...above the level of the radiator cap or overflow bottle. This can be a portion of the upper rad. hose, a heater hose, or a coolant line running thru various parts of the intake/throttle body area. What I do after topping up the system, is let the engine warm to normal op. temp./ W radiator cap still off. When upper hose becomes hot, you know thermostat is open. Now, if a bleeding device is not present, back off a hose clamp at the highest point in the system. Take a pair of pliers and twist the hose just enough to break the seal. You should see steam or drops escaping from your "breach". Once the steam stops and becomes all coolant, you have likely bled all air from the system. Top up radiator and coolant bottle to proper mark and close the system. (tighten your hose clamp) Check for leaks. Keep an eye on your system for a day or two, to insure no leaks are present.

Road

Caution! As with any task that involves opening the cooling system...Coolant and water can become very hot. Hot water and steam can be very dangerous. If you dont feel qualified to perform this task, let a mechanic do it!

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