film build up under radiator cap? on 1991 Pontiac Bonneville

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?

by in Cumming, IA on June 24, 2009
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
2 answers
ANSWER by , June 24, 2009
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 by , July 21, 2010