QuestionRoland,
Please help me understand why my 99 Concorde is not blowing heat and continues to overheat. I put coolant into the vehicle and it still overheats! Yestarday it began to overheat and I let it sit for about 8 hours after adding antifreeze. It overheated again approx. 15mins after starting. This morning i added more antifreeze but it overheated again the only difference is the coolant wasnt smoking, i saw smoke near a built in front of the engine. Any help you can offer will be highly appreciated, i've been burned before and i really need some help, thanks
michelle
AnswerHi Michelle,
There are two main possibilities (and maybe some less likely reasons) for what you are experiencing. One is that the thermostat is stuck shut and preventing the flow of coolant from the engine to the radiator and impairing the flow to the heater core. The other is that there is an internal leak in the engine proper, usually at one of the two cylinder head gaskets which pressurizes the system with exhaust gases and impedes the cooling of the engine and the flow of coolant. If the latter were the case you would also notice excessive white smoke from the exhaust pipe which had the odor of coolant and/or a milky-foamy condition of the oil on the dipstick and/or early after starting the bubbling of gases from the overflow bottle and/or rumbling in the radiator. The former possibility is easy to check and repair, the latter is of course a more significant engine repair job.
So see which if any of the symptoms might be present when you again start the engine and await the rise of the temperature gauge. Also notice whether the cooling fans some on as the temp gauge moves to the high end of its scale. Also let me know which engine you have in the car.
I will add an answer that I gave earlier to a fellow with a similar problem for further info.
Roland
"O.K. that means one of two things: a thermostat stuck shut or a head gasket leak. I hope for the former to be the case.
I would begin by checking the radiator filler to make sure that you have sufficient coolant in the system. If not fill it with 50/50 misture of antifreeze and water, or if you don't have antifreeze use plain water. Also fill the overflow bottle to the lines about midway on the side.
Then look at the dipstick for the oil and see if it looks cloudy or milky rather than clear. If it is cloudy or milky that is a sign of a head gasket leak.
Start the engine and observe whether you ar getting white smoke from the tail pipe in greater amounts than is usual and allow some of it to condense on you hand and see if it smells like coolant. If it does, that is also a sign of a head gasket leak.
If the oil looks o.k. and the exhaust is normal, then the thermostat stuck shut is worth investigating. I am not familiar with the 2.7L engine if that is the one that you have (look on the sticker under the hood or what might be engraved on the engine as to its size). You will see a round manifold with a large upper radiator cooling hose coming into it from the side. That manifold contains the thermostat which you can get at by unbolting the manifold. But you should drain the radiator to remove all the coolant and collect it in a pan for reuse or recycle before opening the manifold. Once you open the manifold you will find the thermostat. Note how it is positioned in the housing before you remove it so you can replace it correctly. Put it in a pan of water on the stove and watch to see if the valve opens as the water approaches boiling. It will be a slight change in shape so look carefully. It it doesn't change then the thermostat is stuck closed and needs to be replaced. After replacement (use a new gasket or o-ring on the manifold) refill the system and see if that solves the overheat problem.
If you have the signs of a head gasket leak then that means a repair in a shop. Is the engine still under warranty? If so that would be good to avail yourself of at a dealership.
Such a leak is expensive to repair (cylinder head has to be removed).
So do those observations and write back with the results."
