Car Overheating? Signs Your Radiator or Cooling System Needs Attention
A Perth summer is hard on a car’s cooling system. Days well past 35 degrees, stop-start traffic, the air con flat out and the climb up into the Hills all push it close to its limit. If something in the system is already tired, that’s when it lets go.
The good news is that cooling problems rarely come out of nowhere. Most cars give you a few warnings first. Here’s what to look for, what to do if it overheats, and how to tell whether you need a flush, a repair or a new radiator.
Key summary
A climbing temperature gauge, coolant under the car or a sweet smell are early warnings. Don’t ignore them.
If the engine overheats, pull over and switch off. Driving on can damage the engine itself.
Never open the radiator cap on a hot engine.
A flush suits an old but healthy system. A cracked or blocked radiator usually needs replacing.
Get the system checked before summer, not in the middle of it.
The warning signs
The temperature gauge creeps up. Most cars sit in the middle of the gauge once warm. If yours starts sitting higher than usual, climbs in traffic or on hills, or a warning light comes on, the system isn’t keeping up.
Coolant on the ground. Coolant is usually green, orange, pink or blue and smells sweet. A puddle or drips under the front of the car point to a leak in the radiator, a hose or the water pump.
A sweet smell or steam. That syrupy smell from the engine bay or through the vents is coolant hitting something hot. Steam from under the bonnet means it’s escaping fast.
You keep topping it up. Coolant doesn’t get used up the way fuel does. If the level keeps dropping, it’s going somewhere.
The heater blows cold. On a cold morning, a heater that won’t warm up can mean low coolant or a thermostat that’s stuck.
White smoke from the exhaust. Thick, sweet-smelling white smoke can mean coolant is getting into the engine, which points to a head gasket problem. Get it checked straight away.
What to do if your car overheats
Pull over somewhere safe as soon as you can and turn the engine off.
Leave the bonnet shut until things cool down, and never open the radiator cap on a hot engine. The system is under pressure and the coolant can scald you.
Once it’s cool, look underneath for an obvious leak and check the coolant level in the overflow bottle.
Call us or your roadside assistance before driving any further.
If you can’t stop straight away, turning the heater to full hot with the fan on high pulls some heat away from the engine. It’s uncomfortable, but it can buy you a few minutes.
What you don’t want to do is keep driving. An engine that runs hot for too long can warp the cylinder head or blow the head gasket, and that turns a radiator job into a much bigger repair.
What usually causes it
Most cooling problems come down to age and wear. Coolant breaks down over the years and loses its corrosion protection, especially if it’s been topped up with plain water. Many modern radiators have plastic tanks that crack after years of heating and cooling. Rubber hoses go hard and split. And a radiator cap that no longer holds pressure lets the coolant boil sooner than it should.
Other culprits include a leaking water pump, a thermostat that sticks shut, a cooling fan that has stopped working, and stone damage to the front of the radiator.
Flush, repair or replace?
A coolant flush suits a system that’s sound but has old or dirty coolant. The old coolant is drained, the system is flushed and fresh coolant goes in. It’s maintenance, and it helps the radiator last.
A repair is the fix when the fault is around the radiator rather than in it: a split hose, a failed cap, a leaking water pump or a stuck thermostat.
A replacement is needed when the radiator itself is cracked, leaking through the core or blocked inside. On most modern cars, replacing the radiator is the more reliable fix and often the cheaper one.
How we check it at Auto Response
We start with a pressure test. It pressurises the cooling system the way driving does and shows exactly where it’s leaking, even when you can’t see a puddle. Then we check the coolant condition, the hoses, the radiator cap, the water pump and the fans.
From there you get a clear answer on what needs doing and a quote before any work starts. That might be a coolant flush, new hoses, a cap, a water pump or a replacement radiator. We do all of them in the workshop.
Frequently asked questions
Can I keep driving with an overheating car?
No. Pull over and switch off. Driving an overheating engine can damage the head or head gasket.
Can I just top it up with water?
In an emergency, water will get you to a workshop. Long term, use the coolant your car is meant to run. Coolant raises the boiling point and stops corrosion inside the engine and radiator.
How often should coolant be changed?
It depends on the car and the coolant it uses, and your logbook lists the interval. If you don’t know when it was last done, we can check its condition at your next service.
How much does a radiator repair cost?
It depends on what’s wrong. A new hose or cap is a small job, while a new radiator costs more. The pressure test tells us which one you need, and you’ll get a quote before we start.
Get it checked before summer
If your temperature gauge is behaving oddly or you’ve spotted coolant on the driveway, bring it in before the heat arrives. Auto Response is at 177 O’Connor Road, Stratton, open Monday to Friday, 7:30 AM to 5:30 PM.
See our radiator repair service, book online, or call (08) 6205 3939
