What the Perkins Engine Thermostat does
The thermostat keeps coolant circulating inside the engine until it reaches working temperature, then opens to send it through the radiator. Running at the right temperature is what makes the engine burn fuel cleanly and keeps the oil healthy.
Thermostats stick — closed, causing overheating, or open, leaving the engine cold, sooty and diluting its oil with unburnt fuel. In our experience it is one of the most frequent findings when a set overheats.
Signs it needs replacing
- Temperature climbing high under load although coolant is full.
- Top radiator hose cold while the engine is hot.
- Engine never reaching normal temperature; heavy soot or wet stacking.
- Coolant leaking from the thermostat housing.
Get the right part first time
Send us these on WhatsApp and our engineers will confirm the exact part before you pay:
- A photo of the engine dataplate — the engine serial number decides the exact part.
- Or the temperature stamped on your old thermostat.
Fitting notes
Fit with a new housing gasket or seal and the correct orientation, then refill and bleed air from the cooling system. A thermostat can be bench-tested in hot water, but given its low cost we usually replace it at major services.
Frequently asked questions
Can I run the generator without a thermostat?+
No. Without it coolant flow is wrong — the engine may run cold or develop hot spots — and it is not a fix for overheating.
What temperature thermostat do I need?+
The one specified for your engine. Many Perkins engines use one opening around 82–83°C, but the engine serial decides.
How often should it be replaced?+
Whenever it is suspect, and as a precaution at major services, since it is inexpensive compared to an overheating failure.