My car is a 2005 Cadillac DeVille, with a Northstar V8. I have exhaust gases coming out of expansion tank. What would be the best head gasket sealer I don't have the money to replace a head gasket?
Bar's Leaks Head Gasket Sealer may do the trick, but, given you have a combustion side head gasket leak, it could potentially not work. It depends on the size of the leak. It's probably not worth throwing that much money at. Those are DOHC engines (Dual Overhead Camshafts), and they're quite labor intensive to replace. Did you ever change your coolant? Coolant needs to be replaced every 3 to 7 years (see your owner's manual for your specific car). Otherwise, the coolant becomes acidic and gradually destroys the head gasket. It's made of aluminum and is quite delicate.
if you use sealer, you might end up worse off than you started.
For example with a head gasket that still leaks, but clogged heater core , radiator, or thermostat.
