I have a '96 Chevy Monte Carlo with the 3.4L V6 at 199,000 miles. Had it about 1 1/2 years and it runs pretty good for the most part. But I'm having trouble wit the heater. While I am driving, the gauge will fluctuate between 120 and 180 (sometimes higher) degrees but the air will blow almost exclusively cold air. When the gauge dips down near 120, it will blow warm air but the majority of the time the gauge sits at 180 and blows cold. I have the temp controls set on the warmest setting so I am at a loss as to what's wrong. Any help would be appreciated (it's getting WICKED COLD in the mornings around here!). Thanks,
SK

?? You mean engine temp gauge fluctuates between 120 and 180F?? Neither are correct operating temps and temp shouldn't fluctuate. I don't really trust that gauge reading so try another way to observe the actual temps. This behavior is more like that of an overheating engine but the temps mentioned don't indicate that. It this full of coolant and holding pressure in the system right now when it warms up?

T
Tom Greenleaf - MetroWest Boston - USA
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http://www.autoacsystems.com/tomgreenleaf/