1991 Pontiac Bonneville Q&A

1991 Pontiac Bonneville Question: film build up under radiator cap?

i let my car sit in the garage for a year and a half , did an oil change and it runs fine, but there is a brown film, under the radiator cap? will a flush work? -
Answer 1
I would flush the cooling system and possible remove the thermostat while flushing the system and replace the thermostat and radiator cap and antifreeze when servicing the cooling system When using a cooling system flush product like Prestone cooling system flush I like to flush the system out well and add a few table spoons of baking soda afterward to ensure acids have been fully neutralized. -
Answer 2
DON'T KNOW. WHAT TO DO -