I have a 97 4runner that runs fine until I turn on the AC, then it overheats. I'm not sure where to start. Does anyone have any ideas?
- posted
19 years ago
4runner overheating
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- posted
19 years ago
Radiator.
If the temp is fine with the A/C off, it's probably not the water pump or t-stat.
Does go into the Red when it overheats or just below the Red?
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- posted
19 years ago
The a/c puts a hell of an additional heat load on the cooling system. So, your system could be on the verge of having problems and that extra load pushes it over the edge.
Are you flushing the system every couple of years? If not, your tubes could be blinding. I would start there with a good flush and fill if that hasn't been done in a long time. The heat transfer coefficient of your radiator and the rest of the system drops like crazy when scale and/or rust starts to build up - so, it pays to keep that stuff out of there. As I have said before, always use distilled water to fill your radiator - it doesn't conduct electricity worth a damn and that's a good thing in a automotive cooling system.
Other than that, you are looking at either the thermostat or the water pump, I would think.
Luther