Q: This is Luis from Mesa, AZ. I have a 2000 Maxima. Temp gauge rises when coolant level is normal, but when level drops, gauge reads

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When radiator is topped off, and reservoir is to max level, temp gauge rises over time, unless heater is on full blast. However there seems to be a leak, and when coolant level drops after about 3 days or so, temp gauge drops to normal again. So I'm wondering if a damaged coolant temperature sensor needs replacement. And regarding leak, when engine is cold or just hasn't been running after about an hour, white smoke comes from exhaust for about 10 seconds then disappears. Havent pressure testet radiator yet for leaks, but can this be a sign of possible internal leak? Engine oil shows no signs of coolant, and engine runs in great condition (168K miles). OBD does NOT give me any p0300 codes for misfires at all, though I made the mistake of running engine with aftermarket ignition coils for about 5 months, which triggered p1320 code before replacing with OEM coils. Thanks for your help.

My car has 168000 miles.
My car has an automatic transmission.

Hello Luis, thank you for writing in. If the vehicle is leaking coolant, and you are seeing white smoke or steam from the exhaust, then your engine is consuming the coolant. This happens when your head gasket allows coolant to flow into the combustion chambers. It is also why you are likely only loosing coolant when you drive. At this point, do not worry about the other symptoms. Most of them may rule themselves out when the head gasket is repaired. If there has been any further damaged to the cooling system, we can sort them out after the leak is taken care of. Keep in mind the coolant overflow tank needs room in it in case the cooling system heats up and the coolant expands, it needs a place to drain into so you do not loose that coolant. For more help replacing the head gasket, contact our service department to schedule an appointment.

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Hello, thank you for writing in. The vehicle is likely experiencing a coolant leak from a blown head gasket. When the coolant is showing itself in the exhaust in the form of white smoke or steam, we know that it is passing into the combustion chamber. Do not worry about the other symptoms you are having or not having right now, as most of them will be sorted out when the leak is fixed. Do not worry about pressure testing the system until that leak is fixed. If the vehicle is still showing signs of overheating or a pressure issue, you will then want to perform some separate tests. For more help resolving the cooling system issue, contact our service department to schedule an appointment.

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