Karcher Pressure Washer Overheating — Fix

What it means

Karcher overheating is caused by running the pump at idle (trigger released) for too long, which recirculates hot water.
Always press the trigger regularly or switch off between uses.

How to Fix It

Switch off and let it cool

If the machine has cut out due to overheating, switch it off and leave for at least 15 minutes before restarting.
Avoid prolonged trigger-off idle running

When the trigger is released, the Karcher motor continues to run and the pump recirculates hot water.
This rapidly heats the pump.
Never leave the machine running with the trigger released for more than 30–60 seconds.
Switch off between tasks

When moving between areas, switch the machine off rather than leaving it running.
The pump circulates and heats water internally when idling.
Check the water inlet temperature

Karcher cold-water pressure washers cannot operate with hot water from the tap.
Hot water supply accelerates overheating.
Use cold water only unless the model is rated for hot water.
Check ambient temperature

Using a pressure washer in very high ambient temperatures or direct sunlight increases the thermal load on the pump.
Use in shade where possible.
Reset the thermal cutout

After cooling, press the reset button on the motor housing if present, or simply try starting the machine again.
The cutout resets automatically once the motor temperature drops.

Frequently Asked Questions

Can overheating permanently damage a Karcher pressure washer?

Occasional thermal cutout events cause no permanent damage.
Repeated overheating accelerates pump seal wear and can eventually damage the motor windings.
Avoid prolonged idle running.

How long can I run a Karcher before it overheats?

With the trigger pressed and water flowing, Karcher domestic models can run continuously for many minutes.
Overheating occurs fastest when the trigger is released and the pump idles.

My Karcher keeps shutting off every few minutes even when I am spraying — why?

If the machine cuts out while spraying, the thermal cutout may be tripping from a combination of hot weather and a partially blocked nozzle increasing back-pressure on the pump.
Clean the nozzle.