Coolant is black and there are some chunks inside?

1999 BUICK REGAL
116,000 MILES • 3.8L • V6 • 4WD • AUTOMATIC
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IMAGING
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The coolant reservoir is empty. There is about 3oz. in it but it's black and there are some chunks inside. Should I replace the radiator, even though it's not leaking, hoses and thermostat?
Now, I can take out the coolant reservoir container to wash it out. Should I also flush it with some cleaner?
Apr 20, 2021 at 6:00 PM
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JACOBANDNICKOLAS
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Hi,

If the vehicle isn't overheating, I would simply drain and flush the cooling system. As far as the reservoir, yes, remove it and clean it.

Here is a link showing how to drain and flush a cooling system:

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

This vehicle came with Dex cool coolant. It can't be mixed with traditional coolants. So, if it has never been done, make sure to use Dex cool. The only way you can switch coolants is if all Dex cool is removed and then you can flush the system and install something different.

I attached a pic below of the coolant type. Also, it indicates the color as well. Pay attention to what color the coolant is when you drain it.

Let me know if I can help.


Take care,


Joe

See pic below.

Apr 20, 2021 at 8:46 PM
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IMAGING
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So just open the petcock button underneath the radiator to drain out all the coolant.Then just refill the reservoir and radiator cap with coolant or just the reservoir container with coolant?
Apr 21, 2021 at 10:40 AM
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JACOBANDNICKOLAS
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Hi,

If you only remove the drain on the radiator, you will not be getting any of the coolant in the engine. That is fine it if isn't too bad. However, you may want to drain all of it.

If you look at the pics below, they include the directions and pictures specific to your vehicle for a drain and fill. The pics show how to drain the engine block as well.

The directions for refilling the system are also included. When I do it, with the engine off, I fill the radiator and then fill the reservoir to the full mark. Next, I turn the heater on high, start the vehicle and allow it to reach operating temperature, and then fill the overflow as needed.

When you fill the radiator, when it reaches nearly full, slowly continue to fill it. Allow the coolant to go into the upper radiator hose and bleed out air.

Let me know if this helps or if you have other questions. Again, the pics below are directions specific to your vehicle. You do not have to drain the engine block, it just helps get more of the coolant out.

Take care,

Joe

See pics below.
Apr 21, 2021 at 6:34 PM