Car overheats after I fix coolant leak wth?!

[d2fanatic007]

About a week ago, I noticed my car (2000 Chevy Cavalier) was overheating so I checked and saw coolant all over the place and saw that the upper radiator hose was touching the bolt that holds my battery. It burned a whole through the hose and shot coolant out, so I replaced the hose.

Then about 3 days ago and today, I used the heat cause it was cold and my car overheated, I was like :wth:. Turned off the heat and it was fine. The thing that gets me is that it only overheats when I use the heat :confused:. Why is it overheating only when I put the heat on, shouldn't the temp lower? If I don't use the heat the temp stays at normal 195. Suggestions?

[d2fanatic007]

Anyone have an idea? I'm gonna try the thermostat and see if that fixes this overheat problem.

[Easto]

Chance are there is some obstruction or a bad hose leading to the heater element that heats your car (passenger area). When you're not using it the water runs unobstructed. When you turn it on it channels it to the heater which is defective or broken (or the hoses leading to the heater).

[Bastid]

check the fluid agian? when the heater is on?

[d2fanatic007]

yea, no hoses are clogged or leaking. Had the thermostat changed 3 times and a temp sensor replaced. Now it hovers real close to the 260 mark, but not completely pinned like before. Have flushed coolant twice and bleed system.

The heat works really well, A/C is cold and the defroster works. Doesn't matter what I use: Heat, A/C, Defroster, the gauge still goes a little wacky and sometimes the temp reads fine. The fan goes on like normal and works but still shows the gauge going past the 3rd solid line which is 3 notches from the red area.

I looked into the oil to see if coolant was leaking into it, to know if there was a problem with the head gasket but nothing, no smells or any smoke when it reads 260 and I kept driving for 10 mins and then pulled over to check under the hood and nothing engine was warm not hot. Is there a recall or something that I missed or is this car just being a b*tch?!

[Dan]

maybe it's electrical? maybe the water temp sensor is going bad?
http://cgi.ebay.com/ebaymotors/Delphi-WATER-TEMPERATURE-SENSOR-chevrolet-CAVALIER-01_W0QQitemZ230303061205QQcmdZViewItemQQimsxZ20081024?IMSfp=TL081024105001r26029