Not a very specific question. Could you give more details.
I have a 1997 Chevy Malibu with 176k on it. Never had a new engine or anything, runs like a champ. It has been making a knocking noise when its cold.(until car is warm) for a long time now. It still makes a little one while at idle, not loud or can even really be heard though.
Yes they can get in through the bottom of your car and even your engine, but wouldn't do so in cold weather!(:
Your heater core may be clogged. Have the heater core flushed and refill the system with fresh coolant.
Cold engine, extremely cold weather, malfunctioning temp sensor, malfunctioning thermostat.
Yes it should.
Chicago's cold temperatures can be attributed to its geography, specifically its location near the Great Lakes. The cold air masses coming from the north and the moderating effect of the lakes contribute to the cold temperatures even when the sun is out. Additionally, factors like wind chill and cloud cover can make it feel even colder in the city.
thermostate stuck open need new thermostate
The thermostat is probably stuck open, even when the engine is cold.
i heard about it from a friend, went and bought a bottle as i was feeling a cold coming on. the next day i felt way better, and even better still the day after that. i highly recommend it.
If if starts bubbling even if the engine is cold, most likely blown head gasket. If only when engine warm, stuck thermostat.
Normally your dipstick has a hot and cold mark on it. If not check it hot, always check it with the engine running on an even surface.
Not a good idea, you may and probably will crack and warp vital parts. Let it cool down on its own before even adding cold coolant into the system.