Aux fan not coming on by itself...
 

What a great time for my car to heat up, in the summer, on the highway. It's not heating up to the point of overheating, just more so than usual.

I was blowing fuses a year ago on my fan, and found out that it was because the wire leading to the fan was all frayed and chewed up. I fixed it, but it still doesn't come on when it should.

I've grounded the wire attached to the temperature sensor and the fan comes on, no problem.

Is it possible I blew the switch ?

AARON ROCHARD

1976 230.4 W115

This is common on the W115 cars. By-passed the switch on my 1976 300D for years! The switch is a common failure.

Thanks, I justreplace the sensor/switch about 2 years ago, but it was probably before the fuse blowing incident. I will try another replacement.

AARON.

check/flush your radiator. It may be time for a new one. Alternatively, check your radiator/expansion tank cap

Where exactly is my expansion tank cap ?

I have a small hose attached to the top of my main rad cap and it drains small amounts of coolant if the rad has either too much pressure or is overfull.

It has done this every couple of months or so and I panic, but it is usually a false alarm and my levels are still fine.

AARON ROCHARD

1976 230 W115

Gotcha! replace the rad cap asap.

Thanks, will do.

ASAP.

A.