 Don't do it!!!
I personally would not run any radiator sealer on a bet in any of my cars. You have cast iron and aluminum with a bit of copper, rubber and plastic thrown in to the mix in your cooling system.
Assuming the coolant is not changed regularly, it is probably corroded nicely now. A sealer could accelerate the galvanic corrosion process, though they claim not to.
I would pull the car from service and check the entire cooling system. Pull the radiator and heater core and have a radiator shop flush and pressure check them. Pull the water pump and see what the inside of the head looks like now. A good shop will be able to PROPERLY flush your cooing system, which I highly reccomend.
Summer is coming, and you had better not be relying on that sealer to get you to winter again... Ask anyone here who has overheated- the head is usually junk afterward. |