I’m doing some (much needed) maintenance work on the 240 these days, and one thing that has been a problem for the last couple of years is that is will overheat when idling/standing still.
Now, the thermostat was changed a few years ago so in my mind it should still be fine. And water does flow, so it seems to be working as it’s supposed to.
Also did consider the radiator, but hoped it was alright, since all is well temp-wise when driving.
This left the fan itself, and it’s a belt driven fan which has a viscous-clutch.
I tried finding a way to establish if the clutch was gone or not, and after a while I found a test that seems to work.
1. Start the car and run it until warm (important that is warm)
2. Take a newspaper and roll it up
3. Enter the rolled up newspaper into the fan blades
* Newspaper becomes confetti: The clutch is strong and healthy
* Fan stops: The clutch is gone, get a new one.
Outcome nr.2 was what happened to me. So i ordered a new clutch based on the one I had. (like this one)
Clutch arrived, and I removed the fan from the belt pulley it’s attached to. Four bolts needs to be loosened, and then you can wiggle the fan out from the shroud.
Four more bolts to undo, and then you can separate the fan and the clutch.
Started it up and let it idle up to normal temp.. and lo and behold, the temp stayed in the middle of the gauge as it’s supposed to. The Whoooosh sound is back as it’s always been, and my newspaper was no match for the fan blades anymore 🙂
This procedure should apply to most 240s, 740s, maybe even 940s? I have a B23A, but the design is mostly the same all over the range of cars and engines.