I seem to be hearing alot of negative feed back on platinum plugs for the MBZ, why is that? I have a 1986 300E with 189K on it. Should I NOT leave the Bosch Platinum Plugs in. I am not having any problems as of yet.

On that same note, sort of. What is the deal with the split fire, or other multi electrode plugs. Are they really better than normal plugs or is this just more marketing?

Thanx

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1987 300E

I don't know a technician that regularly works on German cars that hasn't lost hours of labor chasing down misfires or poor idle conditions due to platinum plugs. MB specifically advises against platinum plugs. I just don't understand the desire to spend more money on a simple spark plug. If its good enough for Mercedes its good enough for me.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

I couldn't agree more whith Steve. I saw a billboard the other day that had Advance advertising the Bosch coppers for $.69 ea...What a deal. Why spend more for less?? Some Mercedes do have plat's in them (the later ones), but the engines are designed for it.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

quote:

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Originally posted by rich30769:
I seem to be hearing alot of negative feed back on platinum plugs for the MBZ, why is that? I have a 1986 300E with 189K on it. Should I NOT leave the Bosch Platinum Plugs in. I am not having any problems as of yet.

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Thanx for the response.Tomorrow the platinums come out.

rich,

There was an interesting post reply regarding this several months back. To cut to the core of this reply. The person had observed the spark in a spark plug testing machine. The platinum plug has a very small diameter center electrode which produces a very thin spark. The larger electrode of a copper core plug producers a fatter spark. I have had platinums in my 300E for quite some time. I learned about the platinums, have bought a set of copper core plugs, but haven't put them in yet. I wouldn't break a leg getting out there to change them. But do change them when it's convenient.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I had asked this same question a little over a month ago. Based on the responses I got, I will be changing back to the copper core plugs too at the next plug change.

The platinums I'm running have been in for almost one year, about 7,000 miles, and lately I have noticed a slight miss at idle. Again, based on the responses, I'm betting it's due to the smaller spark of the platinum core.

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Mike Tangas
73 280 SEL 4.5

MikeTangas,

I doubt that the plugs would be the cause of your newly developed rough idle. The platinum plugs will contribute to a rough idle, but it would probably be upon their initial installation. Even though the thin spark is the down side to platinum plugs, the upside is that they last a long time. Let us know if changing them cures your rough idle. I suspect that there is something else adding to the idle problem. Changing the plugs will help because they're platinum, but if the idle problem came later, I'll bet there's something additionally involved.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I have the 107 CD-ROM. It talks about maintenance. The owners manual is for a 560sl and says the recommended spark plug is listed inside the back cover. On the CD things are listed by category not by page. To make a long story short: what is the proper (MB factory equipment)spark plug and what gap for an 1983 500sl?

Larry Bible,

I finally found the time to change out the plugs today. Pulled the Bosch platinums and replaced with Bosch copper core. New plugs are in, gapped and properly torqued (I might add, the first time I have ever torqued a spark plug). The idle has smoothed out considerably.

The platinums looked good after one years use, still close on the gap and fairly clean, with only a small black spot right at the platinum electrode. Tomorrow I will give it a short highway hop and see how she runs, during and after.

I checked out the plug wires while I was at it. They look OK, but will need to be changed by the end of the summer just because I don't know when they were last changed by prior owner(s).

I am thinking the rough idle had been there for some time, one of those thing you kinda don't notice when they first start out. Like the changing wheel alignment, as it changes you subconciously correct, never realizing the alignment changed. The roughness was probably there before the Benz went down for the steering pump repair, but I didn't notice it until starting it up after three weeks of down time.


Mike Tangas
73 280 SEL

[This message has been edited by MikeTangas (edited 06-11-2000).]