Hello, I have a Volvo Penta MD5C with a cooling issue: when running the engine for a while at a moderate speed, the temperature buzzer goes off.
The amount of cooling water coming out of the engine seems to be normal. The water is warm, not hot. The impeller looks fine as well.
I removed the thermostat from its housing and checked it with hot water. It opens to about 1 cm (almost 1/2 inch) at 75 degrees celsius (167 F), so that seems to be OK.
Before the temperature buzzer goes off for real, it starts making a high squeaky sound and the warning light starts flashing, exactly at the rhythm of the engine.
Based on these three observations, I'm suspecting there is a problem with the temperature sensor. Maybe the sensor is malfunctioning, or it's something with the electrical connections to the sensor.
My main question is: how can I test the sensor? The sensor only has a single wire going to it, so I'm guessing it's probably an NTC or PTC. What should be the resistance when the engine is cold, and what is the minimum/maximum resistance that signals overheating?
Thanks for your help!
The amount of cooling water coming out of the engine seems to be normal. The water is warm, not hot. The impeller looks fine as well.
I removed the thermostat from its housing and checked it with hot water. It opens to about 1 cm (almost 1/2 inch) at 75 degrees celsius (167 F), so that seems to be OK.
Before the temperature buzzer goes off for real, it starts making a high squeaky sound and the warning light starts flashing, exactly at the rhythm of the engine.
Based on these three observations, I'm suspecting there is a problem with the temperature sensor. Maybe the sensor is malfunctioning, or it's something with the electrical connections to the sensor.
My main question is: how can I test the sensor? The sensor only has a single wire going to it, so I'm guessing it's probably an NTC or PTC. What should be the resistance when the engine is cold, and what is the minimum/maximum resistance that signals overheating?
Thanks for your help!