I just skirted a bullet as I came home from Walmart. After shutting off my car, a few minutes after, I hear water flowing onto my driveway. I opened my hood and see the upper radiator hose (with the clamp still on it) had come off the radiator. I can see that the end of the hose that connects to the upper radiator was somewhat swollen, which probably caused it to pull away. I'll be ordering both upper and lower hoses tomorrow when the dealer opens (Holiday today) and install the upper. Question.....Will I need to do any kind of bleeding of the system after the install of the upper hose? Thanks all.

PS....If this happened while driving on the highway, I certainly would have possible catastrophic engine damage. I definitely lucked out!!!!

 

Has the top of the radiator start to turn from black to a brownish color? Usually that means the plastic is degraded and then the neck where the hoses connect like to snap off.

 

NO, This is not the original radiator. It's a Denso replacement that I had Lexus install in July 2016. The neck looks fine. Do I need to bleed the system after installing the upper hose or do I just keep filling the reservoir once I top off the radiator?

 

It should bleed itself naturally but definitely keep an eye on it for a week or so. You should have to fill the reservoir a couple times.

 

Having experienced catastrophic coolant system failures before, I'm willing to bet that you would have been well aware that a hose popped off on the freeway from the explosion of coolant that would have resulted!

Good thing that it happened at home though. My IS350c did something similar to that once, but it did it at the top of a mountain pass on a Sunday drive with no cell phone service. That was a fun day.

 

I had this happen to me too, in the winter. I had to add water and drive carefully with pauses to my mechanic.
I've added another clamp on the hose to the existing one, after that.

 

I found it very peculiar that the hose was able to come off this way with a clamp securing that end. Was it due to clamp failure, excess pressure, hose failure at that end or a combination of all of these things? The hose has no cuts on that end, other than it being a little swollen at that end. I think I'll replace both spring clamps as well, but would be afraid to add an additional clamp or worm-gear clamp for fear of damaging the radiator bibb.

 

I'd definitely replace the spring clamps along with the hose. Additional clamps are not necessary. If you have excess pressure in the cooling system there are other issues.

 

The radiator cap might be bad - when was the last time it was changed?

 

I did change the cap a very long time ago. I finished ordering from Lexus both upper and lower hoses, 4 OEM squeeze clamps, thermostat with O ring, radiator cap and Toyota Red coolant. I'll change the upper hose with new clamps tomorrow and see how it goes. If all is good, I'll take it to my Indy to get the lower hose and thermostat changed. I'm sure that if the upper hose came off due to the old hose or clamps, it won't be long before the lower hose can fail as well. With our old cars with mileage stacking up, we need to be proactive to avoid a catastrophic event.

 

If I were you I would also inspect the small hose that goes from the radiator cap down to the bottom of the reservoir to make sure it is not clogged with crystals (dried antifreeze).
One possible theory of how this happened is that when you got home and shut off the engine the temperature of the coolant rose and the pressure inside the radiator correspondingly rose. The radiator cap is supposed to lift off its seat and allow pressure to be relieved via that hose to the overflow tank. If this pressure is not relieved bad things can happen - like you saw, The fact that it happened after you got home and not on the road tells me that you have too much pressure in the system - either from a bad cap or a clogged hose or both. This is just a theory - your hose might have just failed from age. But if I were you I would not drive the car until you have a new cap and inspected or replaced that small hose.

 

Thanks Tominpt for the valuable advice. I'm aware of the hose you are referring to, which is connected to the reservoir. That reservoir is not pressurized. Regardless,l will be changing the radiator cap tomorrow as well as the upper hose with new OEM clamps.. Hopefully this will resolve my current issue. I will follow up by see my Indy in changing the lower hose as well as the thermostat to cover all the bases. Thanks for the imput!

 

UPDATE....Changed my upper hose today with New OEM Lexus hose and the squeeze type metal clamps as well as a new radiator cap. Everything looks good after the warm up and a short drive. Temperature is normal. I'm planning on letting it cool off tonight and check again tomorrow for any air pockets and/or need for additional Toyota Red coolant. FYI.... looks like the upper and lower hose might very well be originals as they have that Red and yellow line at the end and it looks original. Wow 23 years with the same hoses! They didn't look bad either, just somewhat swollen at the end connecting to radiator. I'll be going to my Indy to get the lower one changed as well as the thermostat. Still thrilled that the hose failure occurred when pulling into my driveway!

 

i 2nd whoever said radiator cap. (just replace it as well) i bet something is causing excess pressure to build up in the system

 

I'm leaning towards the cause of the hose popping off was a combination of an extremely old upper hose (possibly the original..22 years or close to it) and original clamps. The upper hose was somewhat swollen towards the radiator. The cap was changed once before, but I changed it again yesterday anyway. The temp gauge is exactly where it was before. All else looks fine. The reservoir level does raise and lower during warm up and cool down cycles. PS... I have a new lower hose, clamps, and thermostat which I'm changing soon.