when I stopped my truck after driving approx. 50 miles I detected a hissing sound coming from under the hood on the passenger side. I open the hood and it sounded like the liquid was boiling in the radiator. I also noticed the radiator coolant reservoir was overflowing with brown liquid. I checked the temperature guage but it was not indicating it was running hot. The radiator took some water but it didn’t appear totally empty. Any ideas as to what is wrong?
Well, the “brown liquid” deal makes me wonder when the system was serviced last.
I also wonder about the age of the coolant in that system, but I also have to ask–
Was that brown liquid oily?
yes, it did seem oily.
Year? Mileage? Engine size? Last time you had the cooling system serviced, if ever? How much water is ‘some water?’ This sounds, initially, like a badly neglected cooling system, possibly resulting in subtle but chronic overheating, resulting in head gasket damage. Hopefully I’m wrong on all counts, but that is what it sounds like to me.
Sorry to hear that. I looks like a new head gasket, if you are lucky.
You might change the radiator cap. If it is not holding pressure, the coolant will boil at a higher temperature. Also you might drain, flush, and refill the cooling system with new 50/50 mix of coolant. Get back to us if the problem persists.