I've got a 98 E320 that I've had about 5 years. Recently I've noticed the fuel economy is much lower than it used to be. I know it's not the air filter, because I changed it last year. I started looking through the records, and the best I can tell, it has the original spark plugs (145k miles). I pulled one, and sure enough, it looks pretty bad.

I went to buy replacement plugs, and like all vehicles, there were a slew to choose from. I intend to stick with Bosch, and the parts finder here lists the FR8DPP33 and FR8DPP33+, apparently the Super and Super Plus.

On the other hand, the parts store I went to shows the Bosch 4418 and 4301, apparently the Platinum 4+ and Platinum 2+. These are the ones with 2 or 4 ground electrodes that sort of make an arch over the center electrode.

Does anyone have any experience with these? The Bosch website seems to imply they are better.

For what it's worth, I've had terrible luck with brick and morter autoparts stores giving correct advice, listing correct replacements, selling adequate parts. This goes for any parts, including brake, suspension, electrical, etc.

From what I can see, Fastlane, a link of which can be found at the top of this page, is a parts dealer that really knows what's right for the Mercedes brand. I would absolutely stick with the original spec plugs. Don't get attracted to anything else. The cars run best the way they were made.

Other parts sources can be found online if your into hunting around, and the Mercedes Dealerships will give you exactly what you need. More expensive maybe, but these are just spark plugs, after all.

Mark

i've fixed alot of cars by throwing the bosch platinums everyone sells in the trash and installing the CORRECT bosch plugs. they ain't cheap and you need 12 but they will last far longer than anything else. you probably won't get 5-6k down the road before the wrong 1s start to act up. good luck, chuck.

Thanks marko57 and porkface!

I took the Bosch 4301 plugs back after reading the (huge) thread on plug types. Since the Bosch 4301, 4501, and 4418 are all "newer" type plugs, I stayed away from all of them. The F8DPER and F8DPP33 have been replaced with the Bosch 7422, but I couldn't find any of those local. So I went with the NGK 7090's. So far, so good.

Thanks again.

put the Bosch Copper-Plus in....by all means..do not use the Platinum plug...bad....

You should probably check which engine he has before making that recommendation...

- JimY