A bad ground strap will turn your coolant into thick rust mud because it’s eating the block at an accelerated rate, and heavy rust scale flakes off and powders in the coolant. It could be that your ground strap has been going bad for some time, causing the coolant to turn muddy.Click to see full answer. Herein, why is my engine coolant Brown?This can happen either as a result of a blown head gasket or a head gasket that has been broken down by corrosion. It could also be caused by boiling coolant. Coolant becomes brown from rust. If your coolant is brown, the coolant needs to be drained and the system flushed before it can be filled with fresh coolant.Also, how do you remove engine coolant sludge? How to Remove Sludge From a Radiator Park the car in a flat location. Drain the radiator. Fill the radiator with fresh water. Turn on the car and allow it to run until the fan turns on. Drain the water from the radiator by removing the cap and drain plug. Likewise, what does brown sludge in coolant mean? Brown sludge could be a consequence of mixing incompatible coolants as well as not draining the coolant frequently enough. If the coolant level was low and you are having to periodically top off the system, that means there is a leak and, if so, that should be repaired.How do you know if your Headgasket is blown? How To Tell if a Head Gasket Is Blown: Coolant leaking externally from below the exhaust manifold. White smoke from the exhaust pipe. Bubbles in the radiator or coolant overflow tank. Overheating engine. White milky oil. Fouled spark plugs. Low cooling system integrity.