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Diagnose A Failing Radiator | Jack Miller Parts | North Kansas City, MO

Diagnose A Failing Radiator | Jack Miller Kia Parts | North Kansas City, MO

How to Diagnose a Failing Radiator


The radiator is responsible for helping to keep the engine from overheating. If left unchecked, a failing radiator can cause significant powertrain problems. Here are a few common signs to help you diagnose a failing radiator.

Leaking Coolant

Coolant flows through the radiator before heading back to the engine. If there’s a leak, coolant will pool on the ground beneath the vehicle. In order to diagnose the problem, a professional technician will need to perform a pressure test within the radiator. The mechanic may add colored dye to determine if there’s a problem with the system.


The radiator’s primary job is to cool the coolant that removes heat from the engine. If the radiator isn’t doing its job, the engine will overheat fairly consistently. Although an engine overheating once doesn’t necessarily mean the radiator has completely failed, it should still be professionally inspected.

If the radiator is left uninspected and damaged, the engine will overheat and the vehicle will continue to break down. Addressing the issue as soon as possible could prevent damage to the powertrain.



Typically, coolant is yellow, red, or green. As the radiator begins to fail, the coolant may begin to turn a color similar to rust or oil. That discoloration soon turns into sludge. The sludge will stop coolant from effectively cycling and removing heat from the engine block.

Sludge is a common sign of a failing radiator in vehicles that have a transmission cooler within the radiator itself. When the barrier between the coolant and transmission fluids fail, the fluids will mix, creating sludge.

If a technician discovers sludge in your radiator, it should be replaced as soon as possible. A failing radiator that continuously develops sludge can significantly damage the engine and transmission.


Low Coolant

If the low coolant dashboard warning light comes on constantly, odds are there’s a leak in the radiator. While you could just continue refilling the coolant as needed, that will get expensive over time. It’s more affordable to have your radiator leak professionally diagnosed and repaired or replaced.

Here at Jack Miller Parts, we can check to make sure your radiator is in top shape.

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North Kansas City


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Contact Information

2900 Burlington Ave
North Kansas City, MO 64116
Phone: (816) 474-2900
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