Hello Zhu...I bought a flush for the cooling system and I'm letting it sit until Sunday, per the instructions. I noticed that after she cooled down and I open up the cap she has some pressure built up in the system and ends up spitting some water out, and the water is cool too... Anyhow, will leave the product in the system and dride it normally per the instrucctions and then run a hose through the whole system to see if theclog comes out. She does have that rusty looking water from having sat for a while too... I hope that does the trick b/c she runs fine to and from work w/o any temperature issues... Thanks for the replies and if anything else comes to mind please let me know buddy... Thanks:-)