My '03 Buick Century has sludge in the radiator. Went to a shop to get a coolant flush, but the mechanic said I need to replace my(leaking)Intake manifold gasket. Then flush the coolant. Is this common?

yes it is very common. gm uses stop leak to try and keep leaks down, that is the brown build you see in the resivore and in the rad. i always use silicone around the coolant passages between the head and intake, that works well. have gasket replaced and a flush. let us know how you make out.mws919

Thank you mws919 that info is very helpful. Will keep you posted.

good luck

Could the faulty Intake manifold gasket be the underlying cause to me not getting the heater to blow hot air(blows but not hot)? Any incite is greatly appreciated!

your clean flushed radiator and new thermostat will fix the heat problem if you heater core isn't plugged up.

Hey mws919,

The guy I got lined up to replace the intake manifold gasket asked me what size the engine was, I told him it was a V6(3.1L) to which he replied, it would be more work. Guess maybe he thought the engine was a 4 cylinder? What are your thoughts? Also, to save some money, I am buying the parts myself. I have found 2 different price ranges for the gaskets: $49 and about $85 range. The more expensive one says "complete set" is that the one I need or will the cheaper set do the job? Thank you for all your input.

the complete set is for every gasket in the engine. you are only changing the intake. tell the parts store what you're doing and they will give you the correct set.

at work now, talk to you later.

This fix worked for me last year.

radiators

What's in the radiator is also in the engine,so a good flush is top agenda.

GM used Dex-Cool antifreeze in these cars. If air enters the cooling system it reacts with Dex-Cool (when you have a leak) and forms a dsark brown sludge.
GM says that if you use any other type of antifreeze it will void your warranty---on the '03 you probably don't have to worry about that, so have the leak fixed, flush the cooling system, fill it with water and pressure test it for leaks. If none are found, drain the water and then fill the system with the proper mixture of ethylene glycol based antifreeze.