92 Lexus es300 - Steam and fluid coming out from coolant reservoir tank cap hose?

Today, I parked my car, and noticed a hissing sound with steam coming out from under the hood. I popped the hood, and saw that there was steam and drops of liquid coming out of the open-ended hose that attaches to the coolant reservoir cap. The cap has two hoses that come out from it: one is open ended and the other goes to the radiator. I did not notice the engine overheating when I was driving.

What do you guys think is going on here?


Thank you for the great responses. I just checked the coolant levels in the reservoir tank, and it's almost empty.

My questions now are: Could the steam issue be caused by low coolant levels?

Also, what kind of coolant, and with what proportion of water should I add to reservoir tank?

Thank you

4 Answers

  • Anonymous
    9 years ago
    Favorite Answer

    low fluid will for sure do that and eventually cause serious problems if not fixed immediatly as for adding coolant you can either buy the pre mixed 50/50 antifreeze or just buy straight coolant and mix if 50/50 as stated

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  • 3 years ago

    no longer something it there to enable the coolant out if it get too complete. There must be a hose coming from the radiator to the reservoir ( in on the bottom i imagine) and the hose contained in the proper of the reservoir is in simple terms an over bypass hose. Tim

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  • mark m
    Lv 5
    9 years ago

    Probably due to age, these rubber hoses deteriorate. You probably have a crack or a pinhole leak in one of these 2 little rubber hoses and will need to replace them. I would suggest replacing them BOTH. And by all means, use OEM replacement parts and not the cheap "Made in China" variety sold at Pep Boys.

    Penny-wise, pound-foolish, you know...

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  • 9 years ago

    It sounds like the cap needs a replacement as it is a pressure cap.

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