Edmunds Answers



  • zaken1 12/16/11 9:59 pm PST

    While the engine is cold and is stopped; turn the heater temperature control to high, and then fill the underhood coolant reservoir to the normal level line with a 50-50 mixture of coolant and distilled water. Then remove the radiator cap. Start the engine and see if the coolant level is at the top of the radiator filler neck when the motor idles. Have a gallon bottle of 50-50 mixture of coolant and distilled water handy; so you can refill it to the top if necessary. Fill the radiator and reinstall and securely tighten the radiator cap while the engine is still running; but do this before the engine has run for about 2 minutes; as the coolant will expand and overflow if it runs longer than that. If the radiator was more than a quart low; this may have been the cause of your problem.

    If the radiator was less than a quart low; or refilling did not help the problem; the thermostat should be changed. Use a Premium grade thermostat from Gates or Stant.

  • zaken1 12/20/11 10:13 pm PST

    If you try to reply by opening a new question; I won't get to see what you wrote; so please follow the instructions about clicking the "answer this question" button under your original question to post feedback. Thank You.

  • dnitti 12/20/11 11:08 pm PST

    i tried replacing the thermostat and it still keeps overheating. my next thought would be a
    Coolant Temperature Sensor is going out. anythoughts on that?

  • zaken1 12/21/11 1:06 am PST

    A bad coolant temperature sensor would not cause the hot and cold air from the heater that you have been experiencing. That could only come from something in the radiator, hoses, or water pump. But a radiator cap that was the wrong type, or did not hold as much pressure as it is supposed to (15psi) could cause this.

    It sounds to me like the cooling system may still have an air pocket trapped in it; which is causing this problem. See if there are any air bleed valves near the thermostat housing. After filling the system; you should do something to bleed the trapped air out of the engine. If there is one or more air bleed valves; which look like the ones in this link: (http://www.rockauto.com/catalog/moreinf
    ) you can open them (when the motor is not running) and trapped air will come out of the valve while you pour coolant into the reservoir. When a steady stream of coolant comes out of the valve; shut the valve. The system should then be free of air. If there are no bleed valves visible; it may be necessary to open a pathway for air to come out of the system; by removing one of the thermostat housing mounting bolts (if one of those bolts goes through into a coolant passage) or if none of the bolts go through; it may be necessary to loosen the bolts and lift the thermostat housing up enough to allow the air to come out as you pour coolant into the bottle. This may damage the gasket, so be prepared to install a new gasket if needed.
    Did you recheck the level in the coolant reservoir several different times after changing the thermostat, or did you only check it when first filling it? That level can drop fast if there is an air pocket in the system which comes out. And did you start the motor and fill the radiator while the motor was cold and idling? Did you use coolant that was mixed with equal amounts of water? Also; is the radiator staying full; or does the coolant level go down every few days or weeks?
    Please let me know about each of those questions.

  • dnitti 12/21/11 11:46 pm PST

    ok what i did now was i bled the lines again. it works but when i shut off the car for a while then come back and start the car it would over heat then i bleed it agin and more air would come out then the temp goes back to normal. im thinking that somewhere air is getting back into the lines somehow but i cant figure out where though

  • zaken1 12/22/11 1:05 am PST

    If you have to add a quart or more of coolant when bleeding the system each time, and you don't see any coolant leaking under the car; then there probably is a leaking head gasket; which sucks coolant into a cylinder and pumps exhaust gas into the cooling system. Take the cap off the coolant reservoir, and see if you can smell exhaust gas at the reservoir opening. If you can; that would mean there is a head gasket leak.

    The way to repair a leaking head gasket is to remove the cylinder heads and have them inspected for cracks or warping by a machine shop. If the heads are not severely damaged; they can be remachined. Damaged heads would have to be replaced. This work often costs $1,000 or more.
    If you are not losing extreme amounts of coolant; it often is possible to seal a head gasket leak chemically, without taking the engine apart. There are several products sold for this purpose; but only one of them works well enough for me to recommend. It is called Irontite Ceramic Seal. Some serious parts stores carry it; but if you can't find it locally; it can be ordered from the manufacturer: http://www.irontite.com/. I would not use Irontite All Weather Seal for this. The Ceramic Seal will not work in anti freeze; so the cooling system must be thoroughly flushed out and filled with plain water before using the Ceramic Seal. Follow the directions on the bottle completely. The sealer should be drained out and replaced with 50% anti freeze-water mixture after driving the car for 2 or 3 days. I have saved several engines from expensive repairs with this product. But if there is anti freeze left in the system; it will not work; so it is critically important to flush the system well, and make sure the heater is set to hot when flushing the system.

  • kansasnut 11/01/12 8:39 pm PST

    screw the bleeder valves...this is how you fill these radiators...air does and will get trapped in the heads and upper radiator hose...and the water pump at idle cannot overcome the air pockets....remove the radiator cap..top off radiator,,,.start engine....let it heat up with cap off....continue to top off...some will occasionally spill out.,,when the thermostat opens up(and if there is air in the system) you will see it drop down in the radiator....top it off again....you are not done yet.....have someone else rfev eng 2-3000rpms....it will go down again....(this is the action off stronger water pump pressue pushing air pockets into the radiator....) top it off again....while it is reved up and topped off...put the cap on....let it run a few minutes....shut the engine off...let it cool completely down and remove the cap....and for the first time (at least it was for me) the water was at the top of the filler neck...and I had no more low coolent level warnings..

  • kansasnut 11/01/12 8:50 pm PST

    also, to be safe make sure heater is on in above procedure.
    side note.....if after all this and you still are over heating...and your heater does not work,,,mostly means blown head gasket...a blown head gasket causes many differenet systems because it depens how the gasket is blown...the pistin could blow into oil pasages or water passages..if it blows into water passgaes like it did on me...this pressurizes water passgaes in the head...and once again the water pump in this case cannot overcome this pressure and the heat is trapped and the temperature rises out of control....mine wS GOING FROM COLD START TO OVERHEAT IN 3 MINUTES...

Other Questions Needing Answers


Top Heating / Cooling Heater Experts View More

Rank Leader Points
1. karjunkie 1150
2. MrShift@Edmunds 865
3. zaken1 355
4. docj 215
5. tony78 175
6. 0patience 150
7. alaskanj 120