How to tell if your radiator is failing
Updated 9 Oct 2019
No matter what car you drive, the engine generates extreme temperatures.
Whether you’re in Yulara or Tarcoola, or an area that’s less steamy, it’s mini-explosions inside the engine – the combustion process – that makes the most heat.
The cooling system carries excessive heat away, and the radiator plays a major part.
Essentially, the radiator is a heat liquid-to-air heat exchanger.
Hot engine coolant flows through the radiator, air passes through across its fins and tubes, and the heat transfers from the coolant to the air – easy as.
Now, if your car is overheating, you may be inclined to blame the poor old radiator. Is it actually at fault?
What Are the Symptoms of a Faulty Radiator?
Maybe it’s the radiator that’s causing your car to overheat, maybe it’s not.
Only a professional mechanic can accurately diagnose cooling system problems, but there are few common symptoms for a bad radiator:
- A coolant leak. It’s the easiest fault to find in a radiator, obviously, if you find coolant dripping from the radiator’s side tanks or fins.
- Poor heat inside the cabin. A radiator with a restriction doesn’t circulate coolant effectively, reducing the amount of heat you’ll get inside the car.
- Overheating. Whether you see a plume of steam from under the bonnet or the temperature gauge needle is soaring through the red, overheating is a potential sign of a radiator issue.
It Could Be Something Else . . .
Unfortunately, most of the symptoms can be attributed to other concerns too.
A coolant leak could also be from a bad radiator hose, the water pump, or a head gasket.
Poor cabin heat could be due to the heater core.
And overheating, well, it could literally be any component in the cooling system that causes it.
The point is that you’ll need a proper mechanic to check it out.
What Can Cause a Radiator to Fail?
There are four main causes for radiator problems:
- Corrosion. Seams on radiator side tanks can spring a leak from corrosion, as can the cooling tubes that snake through the radiator.
- Blockage. If the engine coolant isn’t flushed according to the maintenance schedule, it becomes acidic and can form deposits inside the radiator, blocking coolant flow.
- Physical Damage. It’s the most common cause by far. Stones impacting the radiator through the grille cause leaks.
- Seal leaks. The side tanks on today’s radiators are crimped in place, and like all gaskets, the seal between the two can dry out or swell, and leak.
How Much Does a Radiator Repair Cost?
There are two ways a radiator repair can go: a complete replacement or a radiator assembly reconditioning.
With a reconditioning, a mechanic removes your car’s radiator and has it repaired by a specialised shop.
It has a moderate rate of success especially for leaks, although it’s sometimes a temporary repair.
The more common and complete repair is a radiator replacement.
A mechanic drains the cooling system, removes the old radiator, fits a new one, and fills the system with coolant.
Generally, expect the cost to be between $350 and $900 for your radiator repair or replacement.
To get your own quote for a radiator replacement, use AutoGuru’s easy online quoting and booking platform!
Jason is a Canadian automotive content writer with a background in the auto service industry, but he’s been hooked on cars and mechanics since childhood.
One of his first cars was an ’80 Mazda RX-7 that’s sorely missed to this day. A ’68 Ford Torino GT, a ’66 Ford Country Squire Woodie station wagon, and a ’96 Suzuki GSX-R 750 have spent time in his fleet of cars, bikes, and trucks over the past two decades.
Jason’s pride and joy is under construction – a turbocharged ’88 Mazda RX-7 convertible. Also on his resume is CASCAR official certification.