Bosch spark plugs no good?
03-11-2003, 11:52 AM
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87 300 E
Bosch spark plugs no good?
So i heard that it is better to just use OEM spark plugs instead of bosch. My friend had a lot of misfiring problems with bosch and he went back to oem and he feels the power. What do you all think?
03-11-2003, 10:34 PM
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88' 300CE, 02' ML500, 65' Triumph TR4A, 78' Datsun 280Z
Bosch Spark Plugs
My experience with the 4 electrode, platinum plugs has been very favorable: installed them 50k miles ago, nice steady idle, no fouling. If all vacuum lines are OK as well as cap/rotor, maybe new plug wires are indicated if your idle is uneven. They may look good, but their expected life is approx. 100k mikes. I understand any that those with the metal heat shielding rather than rubber are best (Bosch/MB whsl. about $125/set).
03-12-2003, 11:01 PM
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93 300E
All of the technicians recommend the plain oem Bosch or Beru copper plug for this engine. Make sure they are the non-resistor type.
Platinum plugs are specifically not recommended for M103 and M104 engines because the electrode is too thin and causes misfires.
Most technicians will not diagnose your engine if you are running platinum plugs.
The current issue of The Star Magazine has an article about not running platinum plugs, too.
Platinum plugs are specifically not recommended for M103 and M104 engines because the electrode is too thin and causes misfires.
Most technicians will not diagnose your engine if you are running platinum plugs.
The current issue of The Star Magazine has an article about not running platinum plugs, too.
03-14-2003, 02:57 PM
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W124 E36T AMG; W124 500E
I just read in the MBCA publication "The Star" that the 4-electrode Platinum plugs are OK for Mercedes. Only the single electrode is prohibited.
I can't remember if it was Stu Ritter or George Murphy who wrote the article.
I can't remember if it was Stu Ritter or George Murphy who wrote the article.
03-15-2003, 05:40 PM
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93 300E
It's in the Technical & Restoration Forum in the March / April 2003 The Star Magazine. It doesn't say who exactly wrote the reply, but it was probably Stu Ritter:
After I put Bosch Platinum +4 spark plugs in my 190E 2.6, a dealership advisor reprimanded me, saying they arent' recommended by Mercedes-Benz. He said that a service bulletin indicated that they should not be used. Is this so?
Some time ago a Mercedes-Benz service bulletin recommended against using fine single-wire platinum electrode spark plugs in their engines. The electrode on these plugs was so thin that the spark could be blown off the plug, causing misfires. The new Bosch +4 spark plugs are not covered by that old bulletin. Thin-wire plugs could cause poor idle quality and misfires at high rpm under full throttle. Mercedes-Benz has not recommended against the newer +4 plugs, which have four electrodes so are not about to have the spark blown off. You might tell your service advisor that serval versions of Bosch platinum plugs exist.
After I put Bosch Platinum +4 spark plugs in my 190E 2.6, a dealership advisor reprimanded me, saying they arent' recommended by Mercedes-Benz. He said that a service bulletin indicated that they should not be used. Is this so?
Some time ago a Mercedes-Benz service bulletin recommended against using fine single-wire platinum electrode spark plugs in their engines. The electrode on these plugs was so thin that the spark could be blown off the plug, causing misfires. The new Bosch +4 spark plugs are not covered by that old bulletin. Thin-wire plugs could cause poor idle quality and misfires at high rpm under full throttle. Mercedes-Benz has not recommended against the newer +4 plugs, which have four electrodes so are not about to have the spark blown off. You might tell your service advisor that serval versions of Bosch platinum plugs exist.
Last edited by suginami; 03-15-2003 at 05:47 PM.
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03-15-2003, 05:47 PM
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93 300E
Originally posted by JetForeman
That's interesting Paul, can you get them without a built in resistor?
That's interesting Paul, can you get them without a built in resistor?
03-15-2003, 05:54 PM
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95 E320 and 00 C230K SE
It's my understanding that plugs wth built in resistors cause more problems than the number of electrodes or brand of the plug, at least with the 103 and 104 engines with the built in resistor boots.
I've tried a resistor plug and couldn't tell a difference, but went to the non-resistor Boschs because not only were they cheap, but why add another 5k ohms of resistance to the ignition circuit when it really isn't needed. That's why I was surprised to read that they were OK to use!!
I've tried a resistor plug and couldn't tell a difference, but went to the non-resistor Boschs because not only were they cheap, but why add another 5k ohms of resistance to the ignition circuit when it really isn't needed. That's why I was surprised to read that they were OK to use!!
