Overheating is a symptom. It is not the diagnosis.
A cooling system is a loop under pressure, and almost every part in it produces the same complaint: the gauge goes up. A thermostat stuck shut, a water pump that has stopped moving coolant, a radiator packed with road debris and a fan that never comes on all read identically from the driver’s seat. So the first job is working out which one it is, not replacing the cheapest part and hoping.
What it usually turns out to be
The thermostat, more often than anything else. It is the cheapest part in the loop and it fails closed. After that the fan or the fan’s control, which is the same part behind an A/C that blows cold on the highway and warm at a stoplight: one fan, two complaints. The one nobody wants to hear is coolant leaving with no puddle underneath, because that usually means it is going into the engine instead of onto the ground.
How you’d know
The gauge climbs in traffic and drops on the highway
At speed the air moves over the radiator by itself. At a stoplight something has to push it, and that is the fan.
Coolant goes down and there is no puddle under the car
It is going somewhere it should not. Sometimes a cap or a hose under pressure, sometimes into the engine. Worth looking at sooner rather than later.
The heater blows cold once the engine is warm
Usually low coolant, or a thermostat stuck open. The heater runs off the same loop, so it tells you about the engine.
A sweet smell after a drive, or a film on the inside of the windscreen
That is coolant. A hose fitting, or the heater core behind the dash.
It overheated once and has been fine since
Still worth checking. One overheat can warp a head or cook a hose, and the second one costs more than the first.
What we do
Pressure test, to find where it is going
Thermostats, water pumps, radiators, hoses and caps
Cooling fans and their controls
Coolant drained and replaced to the specification your engine calls for
Heater cores and the plumbing behind the dash
A combustion test when the symptoms point at a head gasket
You get the number before the work starts, not after.
Call the shop and describe what it’s doing. If it needs to come in, we’ll tell you when to bring it.
Mon–Fri 8–6 · Sat 8–2Sun closed
| Monday | 8am – 6pm |
|---|---|
| Tuesday | 8am – 6pm |
| Wednesday | 8am – 6pm |
| Thursday | 8am – 6pm |
| Friday | 8am – 6pm |
| Saturday | 8am – 2pm |
| Sunday | Closed |