they're actually hotter than platinum. that's the benefit. hotter spark that is, not hotter temperature rating

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dew
86' 190e 2.3L 16v

In case anyone is still considering Bosch Platinum Quad plugs vs Bosch Copper cores:

History-I installed Bosch Platinum Quad plugs (before joining this group) in both my '91 300E and '95 E320 about a year or so ago. I thought I was doing something good for my cars and in the process improve their performance.

I began to see responses in different threads warning against these plugs for my series of cars.

Several weeks ago I replaced the plugs in the '91 300E, back to Bosch copper cores. The engine lost its slight idle roughness and seemed to get both slightly better MPG and performance.

Last weekend I replaced the Bosch Platinum Quad plugs in the '95 E320. Wow, this car really responded. No more surging under heavy acceleration, the car moves off from a dead stop with less gas pedal application, I am getting at least a 1 mpg improvement in overall driving and finally it just runs better!

My recommendation: Skip the Bosch Platinum Quad plugs and stay with the group’s advice- Bosch Copper cores.

Jeff

Let me chime in with my first hand experience.

In my (sold now) 1990 300E, I used Bosch Platinum plugs. That was the first thing I did after I got the car in 1996. I did not notice any bad things (idle was fine and performance was good). Then I was reading all these MB mailing lists and took them out and pout back Bosch Copper. The Platinums now are in the trunk of my 1991 300E as spares.

So in my experience, the platinums performed well.

I've put autolite copper core plugs in most everything i've had and never had a plug failure. They are cheap, reliable and unpretentious spark plugs. Platinum is for great records and expensive rings. Stick w/the copper for your cars.

Like MB Doc said before, plats should be used in Platinum cars. I put the Quads in my ML430, and it felt a little better, nothing more noticeable.

Used Splitfires with the copper core in the 190E, and tehy worked very nice. I just had a dealer dervice done where the plus were replaced by bosch ones, and you can notice a little difference. Especially with the R16 removed now, I think I want to stick with the Splitfires.

Good Luck.

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Chirag (Charlie) Patel
--------------------------------------------
- 03 Mercedes S600 Sport TTV12
- 97 Acura NSX-T
- 99 BMW E36 M3 w/500+ HP
- 04 Lexus RX330
- 04 Dodge Dakota Quad 4x4 V8

4 Sale:
- 99 BMW M3 E36 Coup with Dinan SC, Upgraded to an RMS Stage 3 with Aftercooler, 12psi, and 500+hp @ flywheel.

Bosch site recommends the 4418 in platnum+4 for M119 engine. I bought some and it turns out that this plug has resistor built in the psark plug. Its value is about 5.8 K ohms. The Bosch copper plugs recomended F8DC4 have no built in resistor in the plug, the resistor is built into the spark plug connector. So be careful in using resistor plugs where it is not called for.
In my case it is not a total lose since I can use it in my Mazda.

For those of you who have used or are using Platinum 4 plugs in there pre '98 Mercedes, did a mechanic tell you this was OK or even recommend it to you? And, was this mechanic a Mercedes specialist? I hope not. I mentioned it at my Mercedes garage and every mechanic there made a joke somewhere along the lines of, "Yeah, put those in your 300E, you could be one of our best customers!" JimT, I am curious as to which Mercedes you put those into. (Maybe it wasn't a Benz, not sure.)

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Mike
-W126C 560SEC 040 Black
*6.0L AMG M117 32v Hammer
-W163 ML320 Brilliant Silver
-W124 300E Pearl Black

The plugs were in my 16 valve these are the 2 that were in it that failed.

Attached Thumbnails

 

Looks like a textbook case of preignition caused by excessive heat or spark knock caused by running cheap fuel in a high compression engine. For more information on how to properly read your plugs see: http://www.theultralightplace.com/sparkplugs.htm

Here are some larger pics: http://sportbikeguy.com/garage/floor/plugread.html

Couldn't it be the heat range problem in that photo description too? I've always heard that platinum-4's are not at all good for pre '98 Mercedes engines. Too hot.

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Mike
-W126C 560SEC 040 Black
*6.0L AMG M117 32v Hammer
-W163 ML320 Brilliant Silver
-W124 300E Pearl Black

You obviously did not read my post above this was NOT from running cheap fuel or preignition!

For my E320, I used OEM spark plugs (they were Bosch).

For my '01 Ranger I tried the Platinum +4s. Both the Bosch web site and AutoZone showed the Platinum +4 as a replacements. Not long after, I was having problems with a rough idle. I ended up taking the truck to a Ford dealership for help, and they refused to proceed with the diagnostics once they found the Platinum +4's installed. They claimed that they were the wrong heat range for the engine, and that they could (would) not proceed without OEM spark plugs installed. The real problem was carbon build-up.

From now on I stick with OEM parts.

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1998 E320 120K mi
1991 Miata 80K mi
2001 Ranger 109K mi

"You obviously did not read my post above this was NOT from running cheap fuel or preignition! "

No, I read your post.

This was brought up on another post and I'm not the only one with this opinion. Call it what you want.

Bosch spark plugs