the whole deal is the little cap on spark plugs that come attached and you have either leave on or remove, depending on your car. On BMWs the little cap has to be removed to fit the wires, on MB you have to leave them on...different horses for different courses...the bottom line is static in the sound system. Now there is the matter of heat rise and disappation on the electrode, my 633CSi required Silbers (as they say in Germany) $10 a pop. Faster heat rise and dispersion than normal plugs, car wouldn't run properly without them...truth...but that was pretty much the last series that those were required.....I say again, just install what the manual says to, and if that particular part has been superceeded go with that. I would not get fancy with upgrades/alternative versions, doubt it'll work

I decoded that to be: 14mm thread,5/8 projected tip, resistor,19mm (3/4" reach)

Non-Resistor version, This should do:
NGK-7405

LOL. :D Holland is the only place I've been where the roads make 0 sense at all. I did a tech project at the schools there.....what a confusing city.

Our 300E is running resistor champions right now, and runs just fine...they've been in it a long time though, so I just ordered some NGK's (probably resistor) and will throw those in when they get here and see what happens....

Tonight I found that the serpentine belt has snapped a cord and is dying....so I need to order a belt! :eek: Annoyingly enough, I just placed an order yesterday for some stuff (lock tumbler) and such....I wish I had known about the belt then!

Summit lists the 7405 as a "manufacturer heat range: 9" and the BKR5E as "...range: 5". The BKR7E is closer to the 7405, possibly the 7942 but there's no direct reference to the heat range. I'll check on the NGK site to see, hopefully you've found the plug series.

Still, as much concern as there seems to be about running the resistor plugs, I've found the resistor copper NGK to work quite well.

There's one at LKQ, I left it there when I scrounged the tensioner LOL.

Don't expect changing the belt on that gasser to be as simple as the diesels, I am beginning to think that the Engineers at Mercedes-Benz were trying to punish people for making them design cars with gasoline engines by making the maintenance so rediculous (in comparison to similar tasks on the diesels).

I think I have found a way to curb my Mercedes buying habit: buy a couple of gassers, cured!

Those have the wrong seat style. Can't use them.

Was the belt in very good shape? I can't remember how new it was/the condition. If it was I'll go pick it up! :)

Maybe the M103 is easier than the M104.....in the FSM it just says to remove the fan, and then remove/reinstall belt. No touching the tensioner or anything! Sounds simpler than the v-belts on a 617......

Yeah, buddy! Welcome to the never ending saga of "what plug goes where."

No, BP5EFS is a non-resistor plug. But I noticed that the NGK website shows the TR5 plug as the substitute for the original Bosch H9DCO, so your vendor apparently just substituted the TR5s when they filled your order. But the TR5 is very definitely a resistor plug and therefore not a true replacement for the H9DCO, but then, even Bosch can't replace the H9DCO with a non-resistor plug anymore. And that's the root of this whole problem.

FYI for anybody out there looking for BP5EFS plugs, ebay UK vendor "doctor_car" has a good amount of them in stock. I sent in a Best Offer to them and got them at a decent price shipped to the US, don't want to say exactly how much, but under $25USD.