Spark plug confusion
 

No, this isn't another typical spark plug thread....


I have an even dumber question......

On my '88 560SEL, as I was troubleshooting the car this weekend, I pulled off the spark plug wires to discover that the spark plug terminal ends were never screwed onto the plugs. I've noticed this on lots of German cars before, but of the 3 or 4 W126's I've worked on, I've never seen one that didn't use the plug ends.

Did the PO just do something dumb, or are there certain models of W126 that don't need the terminal, and the boot just goes right over the screw thread?

Looking into the boots, it's hard to tell - it looks a tad too large to not use the terminal ends, but perhaps too narrow to use them.

They are Bosch OEM style plug wires with the metal boots and the plugs are Beru. It is possible that all I have seen before are aftermarket plug wires? The ones in my 300SE are aftermarket to be sure.....


Thanks......

Depends on the design of the plug caps on the plug wires.

Thanks for the reply.... Any easy or visual way to tell them apart?

plug terminals
 

On your engine the wire terminal end is designed to grip the threads on the plug. The screw-on caps are not used.

but there are only two different ways to do this.....this isn't that hard to determine.....

and you don't screw spark plug wire connectors onto the plug anyway...in
any case....you just don't......

All early MB plug wires were without the button end. An easy way to tell is look up into the resistor end, there will be a spring type clip to secure the wire to the plug end. The large ends are an American thing.
Bill

Thanks for the explanation Bill. I've seen and used these types of plug wires on VWs and such before, but just not any of the admittedly few W126s I've worked on. I think maybe I've worked on 5 different W126s, and one was a Diesel, so not enough to have seen a real cross section of them.

Mainly, I just wanted to make sure that these weren't the wrong wires or plugs for this car.....


Thanks again.