Have to Add Antifreeze to My Ford Bronco Radiator – Do I Have a Leak?

Reader Question Whats up…here’s the history
Thermostat went out on my 1991 bronco about a year ago. It was literally falling apart when i got to it. Changed it and the temp has been fine since. The coolant was badly corroded though. Since changing the thermo I have had to add coolant at the rate of about a gallon a month but temp is never a problem. I do havce smoke but it is grayish, not really white.

Could i have a small leak in the coollant system somewhere since the coolant was so corroded wehn flushed? Or is it more likely the head gasket? I don’t see any leaks but can smell a small hint of coolant when running. When looking at the oil, i can’t see any coolant or water in teh oil either.

One more question…is that sealant that you advertise as good as it sounds?

I might try that after another flush. The coolant still gets rusty looking after a flush too…FYI. I am guessing radiator. Could there be a small enough leak that i could not see it but is escaping by boiling.? Again..tem gauge is normal. What is your opinion.
Thank you so so much for your service


DO NOT use a cooling system stop leak sealant until you figure out what is going on, yes that sealant I talk about works great, but you only want to use it as a last resort.

FIRST….go get a “Cooling system pressure test” done to help locate the antifreeze leak. This is a simple and cheap test and just about any full service mechanic shop can do it for you. Corrosion looking antifreeze is caused by a leak in the system and oxygen being let into the system causing rust, so I would suspect you have a leak somewhere…probably an external leak in a hose, gasket, water pump or radiator somewhere and not a head gasket problem.

Let me know what you find out.


Austin C. Davis

Posted in: Over Heating

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