Bosch Spark plugs
 

Time to tell the truth about Bosch plugs,Today I was on the phone with a rep. from Bosch, He was very considerate and listened to my story of spark plug dilemma of the DIYERS of this forum.He stated to me emphatically Bosch no LONGER MAKES A PLUG THAT IS NON RESISTER,so you do not have a choice of non resister plug from this company.I hope this will help you to make a selection from another manufacturer. The Auto zone people that sold me the plugs are getting an ear full from me and a letter to the head office,for telling a lie that could have damaged a very expensive part. Well I do hope that my former post on this will now stand corrected,And I do apologies for misleading any one.JNT:eek:

Bosch and Beru both make the OE spark plug for Mercedes vehicles that our cars require.

I wonder if the dealers carry the Mercedes Benz branded spark plug that is non-resistor?

I'v been having the same problem. I just went to MB dealer and they gave me W9DC0 plugs in lieu of the W9DC's that my manual calls for they were about $4.50 each. I dont know what the 0 is at the end but all I was able to find otherwize was WR9DC's, which I know are resistor plugs.

John Roncallo

Double check me, but I think the Bosch W9DC crosses to the NGK BP5ES. I've had good luck with NGK's in my ponton and others have spoken highly of the NGK's in other Mercedes applications.

Sokoloff is spot-on here... NGK is a great choice, Beru is OK too (didn't used to be, LOL), but they're much harder to come across.

That's and O and not a 0 (zero) and indicates a larger diameter center electrode.

first thing I noticed comparing my NGK vs Bosch (rusted rotten crap that came out of my car) is that the electrode size.

NGK is so much smaller it's in a whole different league. And you should know now, that the smaller the top, the more concentrated the spark and the more complete combustion.

bosch is a joke.

Yeah, kind of interesting how even Beru is generally considered to be a better product these days... that certainly wasn't always the case. Plugs made in India?? Even the Bosch wire sets are lower quality, caps, rotors and the like made on the cheap in 3rd world countries, etc..

I just picked up an '87 300E which I suspect could benefit from a new set of plugs. from these posts I get the opinion that NGK would be a better choice than Bosch. My experience with my 3000GT was that NGK coppers would last much longer and retain their performance characteristics far longer than Bosch. Does anyone have a recommendation for the 300 as to copper core, platinum or iridium?

Only use a copper core non-resistor plug.

I see a lot of NGK BP5ES being sold on eBay as a motorcycle part.

Yeah, BP5ES are easy to get, all over the net.

TR5 should be the correct plug for the 300E, BTW.

TRS is resistor.

Yeah, unfortunately that seems to be the only choice for NGK on a 300E. Maybe there's another brand option. The resisted plug isn't going to kill his car, though.

Most Bosch plugs are still made in Europe, they still specialize in Cu core and they still manufacture non resistor plugs up to this time. quality may have deteriorated for unknown/ no verification reason/s. All brand that has the same size as bosch can be used, plugs are plugs, their function is to spark and start the combustion, brands are just a psychological and marketing strategy. ask a professional electrical engineer. For langpfeife, as of today the best spark plugs are made in the 3rd world country, brands like NGK & Nippon Denso .