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AdamL · 12-07-2021, 21:03

I have been having problems with the temperature gauge and temperature sensor/sender on my Volvo Penta MD22L

Given the age of the engine, it appears that the temperature sensor had failed.

The sensor can be found in the front top left-hand side of the engine just behind the thermostat housing (22mm hex bolt with spade connectors facing up). The resistance on the failed sensor read 56k ohms cold and 16k ohms warm (obviously the resistance was way to high).

The quote from Volvo marine was A$250 which seemed a little high in my opinion. Found one online out of the UK for A$30 plus shipping.

The MD22 is nothing more than a green Perkins Prima M50.

In the end, the temperature sensor is Perkins part number 2755A007. Thread size is M14 x 1.5.

The new sensor, at 20c the resistance measures 600 ohms, and 80c (i.e. normal operating temperature) the resistance measures 90 ohms.

PS. If you what to check that it is not a problem with the wiring or temperature gauge, bypass the temperature sensor, by briefly connecting the two wires together which go into the sensor. The temperature gauge should read maximum temperature (because of no resistance) if the wiring and gauge are working properly.

Hope this helps those who have been searching for this information like I was.

**GordMay** · 13-07-2021, 04:42

Greetings and welcome aboard the CF, Adam.

**tkeithlu** · 13-07-2021, 06:32

Good morning and welcome, AdamL.

You have independently found a truth about engine (and other) parts. Volvo didn't design and produce their own temperature sensor. They took one off the industrial shelf. They have to maintain a supply of them in their parts inventory, at considerable storage cost for a very small repair market. Ergo, their price for an off the shelf industrial item is likely 10 times the industry price. If you can find the part on the independent market, it will be far cheaper.

In this case a visit to an ordinary consumer automobile parts store probably would produce a temperature sensor that will work in the Volvo. Just take the old one with you, and ask for "one of these."

I have an old Universal M20 genset. The starters and the throttle are order of magnitude 1200 USD from Westerbeke. The throttle was available from a heavy truck parts website for 125 USD, and the starter is available as a Kubota part on Amazon for 65 USD...