250SE extended test drive

After all the recent work done on my 250SE, I wanted to take it for an extended test drive.   Its had motor and transmission mounts, front crank seal, re-sealed power steering pump, injectors, distributor cap and rotor, points, condenser, coil, plugs, alternator, voltage regulator and more done.     The spark had been quite weak and the engine was carboned up.

The Mercedes-Benz club have started running mid-week pop-up drives.  I’m not normally able to attend mid-week events but I have a bit of time at the moment.   This weeks drive was down to Berry via the Royal national park then back via Macquarie Pass.

extended test drive

In order to keep up with the other cars on the twisting roads and steep inclines required a lot of use of the higher rev ranges of the M129.    The car certainly seems to be running better after this extended test drive.    We had four cars on the drive, a R107 380SL 5.0, a BMW 545i and a C250.

extended test drive

While the car is running much better now, I did have a couple of other issues to contend with.

The first was strange behavior from the radio.   It stopped responding to inputs of the buttons, and event more strangely continued to play even after I had shut the car off and removed the key.   This is quite odd as the radio has two power inputs.   A constant 12v and a switched 12v.   It is not supposed to work without the switched 12v.

Disconnecting the battery obviously caused the radio to power down.   Even after a 20 minute coffee break which I thought might reset things, it was still operating strangely.    It powered back up but was still not responding to button inputs.  I could not turn it on, and it remained in standby even after I turned off the car.    As you can see from the photo, the key is out but the radio remained on.

Radio gremlinsI also had a problem where my A/C was not blowing especially cold and would sometimes stop cooling at all.   If I turned it off for a while and turned it back on again, I would get some cold, but it wasn’t that cold.    I don’t think it is low freon because it would be cold for a little while and the compressor clutch remained engaged even when it wasn’t cold.

At one point I was thinking maybe it was an ignition switch problem?   However, I was soon able to eliminate that.   I removed the radio from the car and tested the two 12v inputs with a multi-meter.   The switched voltage was behaving exactly as it should.  Even more oddly, once I plugged the radio back in in, it behaved normally.   I’m not really why it would reset when removed when it didn’t from a disconnected battery.

working radio

With the ignition switch ruled out, and the radio working again, it was back to the drawing board for the A/C.   I will need to have the car checked, a set of gauges should be able to check if the freon level is sufficient.  It may also show up something like a bad expansion valve.

Still, the MBCNSW Pop up drive proved to be a good day out and a great extended test drive for the 250SE.

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>