Engine Overheat Update, please help

Original:
两周前看过coolant液位还是够的,前天仪表显示发动机过热,而且闻到了糊味,立即停车,等车凉了,看到coolant 明显少了,可没见到有漏液的地方.加满coolant后,也没有漏液,跑了几次都没有过热,但是跑到10迈左右,发动机到radiator的管子只有一个是热的,另一个是凉的.又idle了一会儿,两个管子才都热了.是不是thermostat不够灵敏了?还是raditor需要flush?请各位大侠给指导一下,多谢.车是civic, 1993, 175k.

update:
感谢大侠的指导。这两天的检查结果：coolant 明显少了，水泵处有漏液，但象是coolant 和一点点油的混合物。车尾没有白烟，机油没有milky,hose上没有液体。一个月前，我发现水泵处有漏液，送去check and pressure test,说没有问题。之后几天水泵处又没有漏液，我以为它好了，就没再管它了。结果就有过热的情况。是不是水泵坏了pressure test查不出来？head gasket 会有问题吗？多谢指导。

所有跟帖： 

• 水泵, change it together with your timing belt. -色大胆小- ♂ (0 bytes) () 02/21/2008 postreply 07:55:56

• 要马上修. Change Timing belt and pump together $300 -carjack- ♂ (0 bytes) () 02/21/2008 postreply 10:26:13

• 多谢指导.head gasket 不会有问题吧? -kath1236- ♀ (0 bytes) () 02/21/2008 postreply 10:41:47

• Are you sure you have seen oil in the coolant? -biglow- ♂ (0 bytes) () 02/21/2008 postreply 11:35:10

• Wrong click again -biglow- ♂ (292 bytes) () 02/21/2008 postreply 11:38:28

• yes, I saw oil in leaked coolant on the ground -kath1236- ♀ (0 bytes) () 02/22/2008 postreply 06:49:07

• 回复：yes, I saw oil in leaked coolant on the ground -biglow- ♂ (355 bytes) () 02/22/2008 postreply 08:32:46

• 衷心感谢你的答复.就按你说的做. -kath1236- ♀ (0 bytes) () 02/22/2008 postreply 10:55:15

• replace thermostat first,if no change, the culprit should be -fixanycars- ♀ (295 bytes) () 02/21/2008 postreply 11:43:52

• 谢谢以上各位专家.我决定换thermostat,waterpump and timingbelt -kath1236- ♀ (0 bytes) () 02/22/2008 postreply 06:55:55