Antifreeze and normal operating temperature

Maintenance/Repairs
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41

I set the driver info center to coolant temp and watched the digital readout this morning. I haven’t actually ever watched it before. Unfortunately for the sake of discussion (but fortunately for me!) there’s not any true “city” driving on my route. I drove about 15 miles, mostly interstate at 75 mph. The temp on the readout fluctuated between 188 and 194. Outside air was in the low 70’s, and we had periods of mist. So, my thinking is the 194 was the thermostat at it’s opening point, then the air and mist through the radiator cools the engine back down to 188 or so before the thermostat starts to close a bit and try to get the engine back to 195. The gauge stayed more or less a needle’s width left of center.

If mine fluctuates 6-7 degrees on a relatively flat highway with the cruise set, I don’t think it’s out of the ordinary for your temp to fluctuate 15 degrees (I believe that’s the range you described) city vs highway. I think it’s a function of the thermostat and the wind speed through the radiator (by fan and/or by speed of travel).

The GM electric fans are programmed to come on at set temps also (although they also come on when the ac is turned on). If I recall correctly, the high speed fan (second fan that comes on) isn’t even supposed to come on until around 210.

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42

Looks like you’ll have to chase that rabbit first lol.

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43

Lean condition can be caused by vacuum leaks or by an injector not flowing enough indicating possible injector flush need and/or a smoke test for vacuum leaks.

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44

It’s a 16+ y.o. car, so it’s possible there more than one issue brewing.
OTOH, I don’t think you have an overheating problem now.

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45

That what make such an old car frustrating, the nickel and diming along with playing detective. Just about any rhyme or reason is thrown out the window. For the miles though 206,600 that motor is still gets up and goes in a hurry with a lot of torque even with the quirks or character flaws it has which makes it harder to walk away.

46

I don’t know if this applies to your car, we had that code on a ford and it ended up being bad o rings in the plenum. $500 dealer fix. Our mechanic said go to the dealer, they have better diagnostic equipment.

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