Spark Plugs??

[jtupton]

What type and brand spark plugs are some of you veterans using? Recently bought '89 560 SL. Great shape but runs a little rough. Where should I start? Considering injector cleaner, fuel filter, spark plugs and maybe wires.... Any comments would be appreciated.

Thanks.

jtu

[POS]

Bosch is usually recommended, but I don't like Bosch's spark plugs in particular. I use NGK.

[Alkraut]

The original Bosch spark plug is a W9DC0. They are no longer made and are replaced by the Bosch 7607. Bosch recommends the 7911 plug which is the "Super" version and better than original. Gap at .032" - .035". It is not platinum (which are generally not recommended for the 560SL). If wires are original, you may want to replace them. Also air cleaner element. Don't forget your fluids like engine oil and filter, coolant, brake fluid (M-B recommends changing it regularly), power steering fluid and filter (in holding cannister), transmssion fluid and filter, and rear differential gear oil. Good luck.

[MC06A]

Originally Posted by Alkraut

The original Bosch spark plug is a W9DC0. They are no longer made and are replaced by the Bosch 7607.

I just picked up 8 W9DC0's from my dealer on Tuesday. $4.76 each.

[Go2SL]

Go with NGK. Go to clubplug.net put in part# BP5ES pay $1.80 a plug and smal shipping fee and in days you got plugs, gap is .032 put them in and your car purrs. Its simple

Put in part number on upper right side. If you go by model / year it recommends a resistor plug & you know better than that

[Roncallo]

Originally Posted by Alkraut

The original Bosch spark plug is a W9DC0. They are no longer made and are replaced by the Bosch 7607. Bosch recommends the 7911 plug which is the "Super" version and better than original. Gap at .032" - .035". It is not platinum (which are generally not recommended for the 560SL). If wires are original, you may want to replace them. Also air cleaner element. Don't forget your fluids like engine oil and filter, coolant, brake fluid (M-B recommends changing it regularly), power steering fluid and filter (in holding cannister), transmssion fluid and filter, and rear differential gear oil. Good luck.

The original plug was Bosch W9DC (copper) or W9DP (platinum), neither of which I cant find anywhere today. The new replacement plug is W9DC0 which I am still able to get from the MB dealer only, at about $4.50 a plug. I recently replaced my Bosch Platinum+4 plugs with Bosch W9DC0. There was absolutly no difference in performance between the 2. I replaced the Platinum+4's at the recomended 30K interval. I dont belive I would have had any difficulty at all going to 60K miles on these plugs. There is no problem with Platinum +4's but I dont belive you will get any more performance with them. The good news is you can walk into Pep Boys and order a set of Bosch Platrinum +4's for a 560SL and they will have them in stock and I belive they are under $2.00 a plug.

John Roncallo

[jtupton]

Go2SL Thanks for the advice about the NGK plugs....changed mine today and they do make it "purr". Runs much smoother. $2 each at local NAPA Store.

jtu
89 560 SL

[sublettd]

You can pick up the W9DC plug from Fastlane or ********AZ either one. The fact the original plug is not available has to be an urban legend.

[Roncallo]

Originally Posted by sublettd

You can pick up the W9DC plug from Fastlane or ********AZ either one. The fact the original plug is not available has to be an urban legend.

About a moth ago I ordered 16 W9DC plugs from Fastlane. I got 16 WR9DC and had to return them. Then I ordered 8 W9DC from Performance Products. I got 8 WR9DC and had to return them. Then I went to my local MB dealer and got 8 W9DC0's as about 3 times the price.

John Roncallo

[sublettd]

John,

I don't know what to say. I just installed a set of W9DC that I got from one of the two places I mentioned above. Would have to check the paperwork to see which one, since I have bought quite a few parts of late.

Trying to track down the cause of a stumbling problem by replacing those parts I know are, or soon will be, in need of replacement. Have replaced plugs, wires, vacuum fittings, injector holders, seals and o-rings, swapped ignition control unit, idle speed control valve and idle speed control unit (to no avail). Rcv'd fuel filter and accumulator today--along with a fuel pump, which I don't plan to install--and will install tomorrow. Had a leaking radiator and recently replaced that, too.

I've picked up several parts off of eBay at great prices during the five years I've owned the car. So, I'm not out as much as I could be if I was having to purchase the electrical parts in particular. The car runs great, but I hate that it doesn't start like it should.

[Roncallo]

Well I do remember a post here from Roy at FastLane stating we have NonResistor plugs so maybe there was a temporary supply problem because at the time everyone was complaining abot not being able to get them.

John Roncallo

[sublettd]

I read numerous threads on the topic and was surprised to be able to find them so easily.