Warm Up


New Member
Oct 7, 2003
Houston, TX
How long does it take the 4.6L Mustang to warm up to full operating temp on say a 70 deg day? It is taking mine about 10 minutes with some stop and go driving. When it's cold outside (say freezing), it takes at least 5 min. before I can get any warm air from the heater.

Is this normal, or is my thermostat mabye sticking?
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Your engine is operating normally. There are 2-3 gallons (I don't recall the exact volume) of coolant that have to be heated up from ambient to >100 F before you start feeling some warm air from the vents in the winter. If you have not done it, flush your coolant system out and replace the t-stat (o-ring goes on top of the t-stat), and add a bottle or two of Water Wetter. A clean system transfers heat better.