Last year it started overheating when I run the air but didn't think nothing of it cause it didn't start till the end of summer over the winter I forgot about it. It is still doing it thought It has a new thermostat so I know thats not the problem. We put a water pump on it about 2 years ago so that should have nothing to do with it either. Any ideas of what could be going on and why it is doing this?
2006-07-25 06:58:29 · 4 answers · asked by shellshell 4 in Cars & Transportation ➔ Car Makes ➔ Dodge
the radiator has about a year or so ago been flushed and no he changes the coolant yearly(one of his things lol)
2006-07-25 07:14:24 · update #1
As some of your other respondents have noted, turning on the air conditioning adds to the heat load the engine is placing on your cooling system, as the engine must labor harder to run the comrpressor.
The first thing I would look to is whether or not your truck has an auxhiliary electric fan (two fans total) with the one designed to come on when you turn on the air conditioning to improve air flow through your radiator. If one of the two fans is never coming on, it is either a bad fan motor, or a bad switch or connectiion.
Next, look to the condition of your coolant and of the radiator. Antifreeze is not much of a heat condcutor really, and is mixed with water, which is a good heat conductor. The purpose of the antifreeze is to prevent rust/corrosion in the cooling system, but too high a proportion of antifreeze for your climate can reduce cooling capacity. I would also look to the condition of the coolant. If it is old, flush the system and replace with an antifreeze/water mixture in the correct proportions for your climate. Old antifreeze loses its corrosion inhibiting capacity and can result in the formation of a corrosive layer on the inside of the radiator which effectively acts as an insulator to slow heat exchange. As a consequence, since the truck already had more heat strain on it in the summer, and you add on the heat load from running the compressor for the air conditioning, you may simply be overheating because the system is marginal.
A couple of other points, just for the record. Yes you do have a second radiator of sorts up front but it does not function to supplement your cooling system. Rather it serves to cool off your air conditioning system's refrigerant. Some cars and trucks also have a supplemental oil cooler up front or a transmission oil cooler if you have a tow package.
Also, while it is possible for a bad thermostat to cause a car to overheat, it is not terribly common, and only results from a special set of circumstances. Most of the time when a thermostat fails, it is designed to fail in the open position. Accordingly, it simply allows coolant to circulate freely and does not fulfill its mission to maintain the engine's optimum operating temperature by opening and closing at appropriate times to keep the engine at a realtively constant temperature, say 180 degrees farenheit. If it failed in the closed position, the engine would overheat within minutes under all conditions, summer or winter, air on or not, as the coolant surrounding the engine could never be replaced with the coolant from the radiator, and so it would overheat very quickly. So the only way a bad thermostat can result in overheating is if the thermostat is stuck in the partially open position, restricting flow, and this is easy to check.
In the morning start the truck and keep your eye closely on the temperature guage. If it slowly climbs for several minutes until it gets to operating temperature, and then, slightly drops back, it will signal that the thermostat is working. THe slight dropping back would be indicative of the thermostat having opened properly to admit new coolant from the radiator. Of course this test will not work if you have been running the truck for awhile as the temperature guage is not very sensitive, and the coolant in teh radiator, while cooler than that in the engine, is not so much so that it will produce a noticable drop on the guage.
2006-07-25 08:47:42 · answer #1 · answered by anonymourati 5 · 1⤊ 0⤋
Water cooled engines overheat because the coolant flow is not keeping up with the heat demand. You put on a new water pump and I would be inclined to rule that out. It is possible to get a bad thermostat out of the box, but it sounds like your or your mechanic boyfriend knows something about the truck.
It's a '96, which means it's 10 years old. Has the radiator ever been back flushed or rodded out that you know of? Also, since you replaced the water pump two years ago, the coolant is probably two years old. Might be time to replace it.
2006-07-25 07:08:18 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The air conditioner compressor creates heat. Your cooling system has to cool this heat. There is a second "radiator" either infront of or behind the main coolant radiator used to cool the HVAC system. (Forgive me for not using the proper term, trying to keep it simple) That's why the radiator fan typically kicks on in most makes/models when you turn the air conditioner on. Just turn it off for a few minutes, allow your car to go back to normal temperature, then turn it back on. If the radiator fan isn't turning on when you turn the a/c on, is it turning on at all? If it is, then either your make and model isn't equipped as such, or there's a faulty relay, probably in the underhood fuse box, if so equipped. If the fan isn't coming on at all, you have bigger problems.
Copied over from the original question. If any further information is supplied, I'll answer to the best of my ability.
2006-07-25 07:19:40 · answer #3 · answered by sovereign_carrie 5 · 0⤊ 0⤋
Get your radiator flushed and the correct amount of coolant back in it.
2006-07-25 14:55:51 · answer #4 · answered by xeson1 2 · 0⤊ 0⤋