这个老白也还算熟悉,+ I1 ^7 L: g1 w0 M0 T" K! V: ^
1. low coolant level5 P% ?. I& e, Z" k. @7 l5 W% Y
2. thermostat is stuck open ' b2 t Z: Z0 H r# g5 w3. fan motor does not run well ) t0 a# b' \- T u0 d' P4. heater contorl valve blocked- |6 t; |% }$ m4 C) y# l2 R
etc