More M103 low oil pressure troubleshooting

As a recap, my 1986 300SE started showing low oil pressure. I tried changing the oil and filter, replaced the sender and checked with a mechanical gauge. Still low oil pressure. I decided to do some final oil pressure troubleshooting before I took it into a mechanic to lift the engine and remove the sump.

I was advised on the ozBenz forum that another possible cause was the oiler tube for the camshaft coming loose. The oiler tube is held down by a couple of bolts that if overtightened can strip the threads. Since I don’t have a lot of […]

Testing M103 Oil pressure with a mechanical oil pressure gauge

In my last update, I had ruled out the sender unit when it came to the low oil pressure readings on my 300SE. My intention had been to take the car to a mechanic to test it on a mechanical oil pressure gauge. Two things changed that. Firstly, my area of Sydney went into lock down. Secondly, most mechanics are on holidays until after the new year. I therefore purchased my own mechanical oil pressure gauge off eBay.

I hooked up the gauge and sadly the results were much the same as the dashboard gauge. The mechanical oil pressure gauge […]

M103 Oil pressure sender

A few weeks ago my 300SE started to show low oil pressure on the gauge. It happened all of a sudden while on a drive. At the time, I surmised that I had a dead M103 Oil pressure sender. They are apparently a common fault. I ordered a new one and fitted it today.

The M103 oil pressure sender can be found on the side of the oil filter housing at the back of the engine. Most of the threads you’ll find on the various forums are referred to the W124. Apparently on the W124 space is tight and it […]

300SE low oil pressure gauge

Today I took my 300SE on a Mercedes Club Pop up drive. The Pop up drives are short notice mid-week drives. I normally take the other cars to club events, but the 300SE had not been on a decent run for a while and the weather was terrible. The drive was down through the Royal National park to Mt Kembla, Mt Kiera and then back.

The other cars on the drive were rather varied. There was a Ferrari 458 Spider, an Audi SUV, a race prepped Toyota Yaris and a couple of other Mercedes including a C63, C250 and E400 […]