Step by step approach to solve overheating in the Diesel engine generator.

Temperature switch: what is it?

A temperature switch is a mechanical device that regulates temperature in manufacturing and industrial operations by turning switch contacts ON and OFF when the coolant reaches a predetermined temperature range. This switch is a portable and economical way to gauge the temperature in applications with limited space. 

These switches' switching conditions mainly fluctuate depending on the input temperature. Therefore, this feature serves as overheating protection. Thus, the primary function of these switches is to keep an eye on machinery and equipment temperature.

The sender.

The sender displays the engine temperature on the control module, but a controller can also utilize it to shut off the engine at a predetermined temperature. Depending on the sender installed, the resistance or voltage varies according to the coolant temperature.

Consequently, why may the generator be turning off?

1. The coolant for the generator is scorching.

   As the engine runs, the coolant heats up. The engine fan blows cool air through the radiator's fins as the coolant is pumped through the radiator to lower the coolant's temperature

The coolant sender may have reported a reading that is too high, or the coolant switch may have displayed a fault often by closing if the coolant is too hot. In either case, the controller will act to shut down the set.

2. The radiator fins are dirty both internally and externally.

The radiator fins have accumulated dust and oil. They cannot allow enough air to pass, the pipes that convey the coolant are clogged, and the interior of the radiator has corroded. 

It can occur if you use the wrong coolant/water ratio, the wrong kind of coolant, or you don't change your coolant at the recommended intervals. Take the radiator out for pressure washing and internal flushing.

3. Wrong setting!

If the device is programmed to shut down on the transmitter, it might be doing so too soon. The controller turns the resistive or voltage value the sender sends as a temperature. Verify that the engine's controller set point is accurate.

4. The thermostat is acting up.

The thermostat, which opens when the engine warms up to let coolant circulate through the radiator, has failed. Installing a new thermostat is necessary if the old one has died. Verify and replace the thermostat

5. Water pump.

The Water pump may have broken down, preventing the coolant from moving throughout the system. You would need a new water pump in this situation.

6. Fan Belt.

A belt is required to power cooling systems. The radiator fan and DC Alternator, as well as other components of the generator's cooling system, are all powered by fan belts. Fan belts that work properly aid in radiator cooling. 

Unfortunately, if the fan belt doesn't work as intended, the engine won't be effectively cooled, which can cause overheating and expensive repairs. It is why you do regular inspections; You need to inspect the fan belt to see if it's slag or cracked.

7. Airlock.

If you have just filled the unit with coolant, there may be an airlock in the generator cooling system, indicating that the coolant level is too low and the system is heating up. In this instance, after removing the airlock, add extra coolant.

When the engine shuts down on overheating, and the coolant doesn't boil?

Where to concentrate;

Temperature switch.

The coolant switch misled the control module by reporting a malfunction.

Check for broken wires and a closed circuit to determine if the switch is operating correctly. A coolant switch wire shortening can also cause this problem to the ground. The same condition would also manifest if anything conductive touched both the switch and the engine frame at the same time.

It will indicate either a water pump or thermostat failure; the coolant near the switch is too hot as opposed to being calm in the radiator.

The coolant sender displays an extreme value.

What is happening?

The circuit's electrical resistance or voltage is incorrect; the sensor or the course may be at fault. It can be measured, tested, and verified that it meets specifications without the assistance of the Control module.

The coolant is not in the sensor, which causes it to read the air temperature (airlock). Reinstall it after removing it to ensure that it is in the coolant. When you remove the sender, steam may emerge from the coolant since it may be hot if it has overheated.

A faulty water pump or thermostat, if the coolant around the sensor is too hot in contrast to the radiator, is excellent.

You can test for a faulty switch.

To test the temperature switch unplug the engine temperature sender. Remember to keep the control turned on! The button will safeguard the engine, but a coolant temperature reading won't be available.

Run the engine once more to check if the issue still exists. Assuming that the coolant is above the switch's limit, the controller may be defective if it shuts the engine off. 

If the fault does not continue, either the sender, the sender's earth, or the control module is at fault. You can run the engine temporarily without the sender attached.

We advise you to examine the switch. The engine should be exposed to the ground when it is cold. If it isn't, a replacement is required. Replace the switch by removing it.


Remember that the radiator may be pressurized and extremely hot if you remove the cap. Take the necessary safety measures. If the coolant has overheated, it may also be quite hot and dangerous, and opening the lid may cause steam to escape.


Overheating in a diesel engine generator can be caused by various issues, and the appropriate steps to resolve the problem will depend on the specific cause. Here is a general approach you can follow to troubleshoot and fix overheating in a diesel generator:

  1. Check the coolant level: One of the most common causes of overheating in a diesel engine is a low coolant level. Make sure that the coolant level is at the correct level and refill if necessary.

  1. Check the cooling system: Ensure that the radiator and cooling fans are functioning properly and that no obstructions are blocking the airflow through the radiator. Also, check the hoses and connections for any leaks or damage.

  1. Check the thermostat: A faulty thermostat can cause overheating by not allowing the coolant to circulate properly. Test the thermostat to ensure that it is functioning correctly.

  1. Check the water pump: The pump is responsible for circulating the coolant through the engine. If it is not working properly, it can cause the engine to overheat. Inspect the pump for visible damage and test it to ensure it functions correctly.

  1. Check the exhaust system: A clogged or damaged exhaust system can cause the engine to overheat. Inspect the exhaust system for any visible damage or blockages.

  1. Check the air intake system: An air intake system clogged or damaged can cause the engine to run too hot. Inspect the air intake system for any visible damage or blockages.

If you have checked all of these components and are still experiencing overheating issues, it may be necessary to have a professional diagnose and repair the problem.


Popular Posts