Steam coming from radiator cap?

I have a 1990 Honda Accord. My radiator was leaking coolant so I replaced that today and actually replaced the radiator cap about a week and a half ago. However there is still steam coming from my radiator cap... I replaced the thermostat about 6 months or so ago. My engine is not running hot. Any ideas what could be the problem?

6 Answers

  • 1 decade ago
    Best Answer

    If the radiator cap is aftermarket, replace it with a genuine Honda cap. Aftermarket radiator caps are really shoddy. This is my top suspect.

    If the steam still comes from the cap when a Honda cap is put on, the neck of the radiator is probably cracked. It isn't very common in Hondas but it isn't exactly rare, either... but I don't think I've heard of it in a new radiator. Finally, if the hose to the reservoir is bad (plugged or cracked) that would account for it. When all those pieces - radiator neck, cap and hose - are good there won't be steam from there even if the engine were to overheat.

    Source(s): 35 years maintaining my own cars, including 8 years with my daughter's 1993 Accord
  • Mumsey
    Lv 5
    1 decade ago

    Are you sure you got the proper cap for the rad? Whatever you do do NOT remove the cap when the engine is steaming it will blow coolant 15 ft in the air. It could be that the seal around the cap is wore out.

  • 1 decade ago

    The damage may have already been done. It sounds like you have a blown head gasket. You will need to have a shop do a "block seal test" to confirm the problem. If the head gasket is blown and needs to be replaced it will cost about $600. Or you could just drive it til the whole engine blows and trade it in.

  • JOHN B
    Lv 6
    1 decade ago

    Caps are rated to pounds of pressure. It may be rated wrong. should be in owner's manual. To insure good seal turn to stop then push down on cap and twist some more.

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  • 1 decade ago

    Sounds like you may have a bad radiator cap, or may not have it tightened securely. Hope this helps.

    Source(s): 35 years fixing my own stuff
  • 1 decade ago

    make sure you got the right temperature thermostat and the right pound radiator cap.

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