painlus said:
how often should these hoses be replaced? Sooner or later thatn the manual? 
Replacement of the cooling system hoses is not specified for any particular mileage or time interval in the maintenance schedule in the owner's manual and service manual. An inspection
only is specified for every 30K miles or 24 months, whichever comes first.
While a hose in really poor condition may be found to be so by sight or feel, I am not confident that an inspection every 30K/24 is sufficient to catch them before they fail. Like the timing belt, the cooling system hoses are made of rubber, and over time they can dry out and crack. I consider it a wise and prudent investment to replace the cooling system hoses every 90K miles or 6 years, whichever comes first, just like the manual specifies for the timing belt (or 105K/7 years in the case of the '97+). Furthermore, if you replace the hoses at the same time as the timing belt, it will make it easy to keep track of when you have had this done, and when to do so in the future. Assuming, of course, that you replace the timing belt and water pump at the same time. (There are some efficiencies in doing the cooling system hoses at the same time as the water pump, also, since the coolant must be flushed in either case.)
Incidentally, while the damage caused by the failure of a cooling system hose may be less than that of a timing belt failure (assuming you don't continue driving with an overheated engine), the probability of this happening is apparently higher, since the reports of hoses failing have been more numerous. And either one can leave you stranded, usually at an inconvenient time and place.
Of course, those who prefer to risk becoming stranded rather than paying for preventive maintenance on their cars are welcome to ignore this advice.
Anyone in SoFla have the pair of main hoses handy? hehehe
