Hissing noise under hood

Heading to an appointment I started going up a hill when I started to hear a very noticeable hissing sound from under the hood. When I got to the Dr.'s office I opened the hood expecting to find a hose that blew. Nothing was wet and I checked all the fluids ,they were all fine. I left the office to chance going home and after a few miles the hissing stopped. Two days later on my way to dialysis the check engeine light came onwhen I was just about there. After my treatment (late Saturday of course when no ones available) on the way home it started hissing again. the more I accelerated the louder it got and I started to smell something like burnt steam. Can you give me an idea as to what the proble might be and how much it might cost to repair? I’ve already replaced the engeine and I realy can’t afford a nother car right now. Thank You…

It certainly sounds like there is a leak somewhere in the cooling system–or possibly in the heater core.

This vehicle really needs to be examined by a competent mechanic a.s.a.p.
If you do continue to drive it with this problem, you may wind up needing another engine.

As to the cost, that is very difficult to say.
If you only need a new radiator cap, that will only cost a few bucks.
If you need a new hose, that might run to $20. or $30.
If you need a new radiator, expect a bill of…a couple hundred $$.
If you need a new heater core…you don’t want to know.

Please do not continue to drive this car except directly to your mechanic.

Good luck!

Thanks for your reply. Maybe I should have mentioned I’m still getting good heat but I didn’t try the AC, Do you think this matter? I did unscrew the radiator cap to check the fluid and it was full as well as the overflow.