这个老白也还算熟悉," E9 Y# C; S' f' H \2 s8 b. Y
1. low coolant level 2 M& A% x3 j1 u& w2. thermostat is stuck open1 O4 Z+ X' U, S) B: m% w
3. fan motor does not run well/ x3 L1 u6 Z( N8 C/ O1 c$ _& M
4. heater contorl valve blocked3 F. R& `) F9 V2 r, T* {- t$ n" P
etc