Does your top radiator hose look like this?

[takza]

http://tercel4wd.com/upload/view/full/258_mhumd


Notice how it is bulged near the area where it was clamped on both ends. The tear in the hose at the lower left was done by hand...and by putting a finger in the small hole that had "developed" here...fabric and rubber are "rotten"...or deteriorated so far that they have no strength. A new hose...which I just put on doesn't BULGE.

This hose has over 51K miles and 8 years use. I think it is mostly HEAT that causes failures...so the top rad hose is the one to worry most about? Guess I didn't realize it had been on there so long.

I was lucky...since the cut or split or whatever was right at the top...it just lost a small amount of rad fluid...resulting in no pressure in the system...then just some vapor loss.

I had a hose like this go on another car and since I was moving....before I noticed the steaming...the head gasket was gone. But this hose really blew.

[bleakhorizon]

most of the time swelling and deteriation of hoses comes from oil contamination... otherwise the hose is made to stand the heat, and will ususally only crack and get hard over time.....

[takza]

This is a top rad hose...no oil was ever on it. I've seen two of these go bad on different cars....they do not get hard. The rubber just losses any strength and tears real easy...the cord is weak and just pulls apart. It is the heat...since the top hose will be heat soaked more due to heat rising and also being near an uninsulated hood. Swelling and age are about the only indicators. Both hoses were probably US made aftermarket...not Japanese OEM.

[offroadohio]

Coolant hoses are only recommeneded for use up to 75,000 miles. They are supposed to be replaced after that. Like anything rubber they wear out. Heat, age, and coolant break down are the cuases

[Petros]

My factory hoses lasted about twice that, about 150k miles. The aftermarket ones appear to last 75 k.

[offroadohio]

Ive had oem hoses on 200k but that doesnt mean they should still be getting used.

[Petros]

This last summer I just changed out the last of the factory hoses, the heater hoses. My car has 260K miles, the rad hoses were replaced a long time ago, but if the hoses look good, no swelling, and no cracks, I keep using them until they leak. More like I have to remove one for some other servcie reason (like replacing the engine, or flushing out the heater) and if I crack it, than it gets replaced. That is what was so amazing about the heater hoses, they were still good and flexible up until this year. The stress on the smaller hoses is less, even so, they must be using much better quality hoses in the factory than we can buy in the auto parts stores. Perhaps what we can buy in the US is the same crap they put on the US made cars in Detroit. It does not suprise me they are all going bankrupt.

[takza]

I still use the OEM heater hoses at +250K miles. While back I cut the top one to install a flush tee...it seemed OK...but I didn't do a "destruct" test on it...since it wouldn't be much use after that. They make me nervous.

[hberdan]

Eight years and 51,000 miles is pretty good for a radiator hose! I don't see what all the concern is about. With all the cooling system problems these cars have, a radiator hose replacement is a no-worry thing. Gosh, I've gone thru a complete system replacement in almost all of my Tercels, some have had more than one replacement radiator put in, along with water pumps and thermostat housing, etc.
The last time I replaced a radiator, which unfortunately was not that long ago, mileage-wise, I replaced both hoses too. No big deal, if the hoses appear worn, I replace em. I wish I could say 50 or 75 or 100 K miles between replacement, but I don't even track mileage for stuff like that. I check the hoses regularly for bulging and cracking, embrittlement, etc., and replace as needed.
I don't want to be a 100 miles from home on a ski trip or whatever and lose the engine because I'm too cheap to replace a hose (or a belt) here and there. It's all about preventive maintenance.