Servicing Guide · Updated June 2026 · By the Brad Ward Motors workshop team
If your car is overheating, pull over somewhere safe as soon as you can, switch the engine off, and let it cool down before going any further. The single most important thing is to stop driving, because a few minutes of running hot can warp the cylinder head and turn a cheap fix into a major repair. Once it has cooled, the usual causes are low coolant, a stuck thermostat, a failing water pump, a leaking radiator or a faulty cooling fan. At Brad Ward Motors in Henderson we pressure-test the cooling system, find the real cause, and give you a quote before any work.
- Pull over, switch off, and let it cool before going on
- Never open a hot radiator cap, the coolant is scalding
- Most causes are low coolant, thermostat, water pump or radiator
- A failed fan often overheats only in slow traffic
- Driving on can warp the head, do not push through it
- We pressure-test to find the real cause, quote first
What to do the moment it overheats
Pull over safely and turn the engine off. Watching the temperature gauge climb into the red, or seeing steam, means the engine is already hotter than it should be. Switching off stops more heat being made.
Do not open the radiator cap while the engine is hot, as the system is under pressure and the coolant is scalding. Give it a good fifteen to twenty minutes to cool. If you can safely see the coolant overflow bottle is empty, topping it up with water will sometimes get you a short distance, but treat that as a get-to-help measure, not a fix.
Common causes of overheating
Most overheating comes down to the cooling system not moving or holding coolant properly. Low coolant from a slow leak is the most frequent cause, often from a perished hose, the radiator, or the water pump. A thermostat stuck closed stops coolant circulating, and a worn water pump cannot push it around.
On a lot of West Auckland cars that sit in stop-start traffic, a failed radiator fan shows up as overheating when crawling along but cooling down again at open-road speed. A blocked or aged radiator is also common on higher-mileage cars. We pressure-test the system to find which of these it is rather than guessing.
Why you should never keep driving
An overheating engine is the one warning you should never push through. Aluminium cylinder heads warp when they get too hot, head gaskets fail, and in bad cases the engine is damaged beyond economic repair. The repair bill for that is many times the cost of fixing the original leaking hose or thermostat.
That is why we always say stop and call rather than nurse it home. If it is not safe to drive the short distance to us, a tow is far cheaper than a new engine. We would always rather look at a car that stopped early than one that was driven hot.
Getting it diagnosed and fixed
Bring the car to our Moselle Ave workshop, or call and we will tell you whether it is safe to drive in. We pressure-test the cooling system, check the thermostat, water pump, hoses, radiator and fan, and pinpoint the actual fault.
You get a no-obligation quote before any work, and we explain what failed in plain English. Most cooling repairs, from hoses and thermostats to water pumps and radiators, are straightforward once diagnosed, and the job is backed by our 12-month workmanship warranty. Courtesy cars are available on request.
Talk to a real Henderson mechanic
Quotes, no surprises, all makes and models. MTA approved, 35+ years on Moselle Ave.