I am about to replace the spark plugs in my 2001 E320. Car has about 50, 000 miles. I purchased 12-Bosch Platinum 2 Spark Plugs ((4301). Were these spark plugs a good choice? Are there any cautions about removing the coil packs, wires, and plugs? Your advice will be appreciated.

 

Hi,
The OE plugs in my 112 engines are both Beru. can't comment whether Bosch are better / worse etc. I've had zero problem with mine which were changed at 70k and the new set (also Veru) are up tp 40k (110k).
Air cleaner, coil pack and lead removal is straightforward HOWEVER a few of tips.

1. The plug leads can be difficult to get off due to restricted space. Don't pull on the lead. Use an open ended spanner 14mm? and find a position where you can use this as a lever to ease the lead off.

2. The plugs can "weld" into the head if they weren't treated with anti seize compound when they were fitted. I removed mine on a warm engine with no problem but if you do have a problem don't continue unwinding the plug if it continues to be stiff once you have "broken' the seal. Retighten, apply some penetrating oil etc to provide a degree of lubrication and when trying a second time apply an untighten regime, then tighten up a bit and then untigten again etc.. This reduces the likelyhood that the thread will "pickup". Reinstall with an appropriate anti seize compound. I use copper slip but there are many others. Ensure the socket is a good fit Single hex is better than bihex.

3. Note / Mark sequence of A and B coil leads. Its pretty obvious but it is possible to reassemble them incorrectly. e.g. Mark A's with a blob of paint or similar.

4. You will need a 3/8" drive socket set with appropriate extentions and a knuckle helps.. 1/2" is too large

5. DO NOT OVERTIGHTEN the plugs when refitting. Sorry I haven't got the recommend torque figure at hand.

6. Some people put grease or dieelectric grease on the plug insulator to ease lead fitment/removal. I do not recommend this since over time it causes the rubber inside the plug cap to denature at extended high temperature..

Hope this helps. Job will take you first time round about 90 mins. 12 plugs!

Stuart

 

Thank you Stuart. Your advice was very helpful.

 

Bosch platinum are OE plugs on many Benz motors. The best deal I found was www.autohausaz.com And, they are a good resource for finding the right OEM part. Torque on plugs is recommended at 22 foot pounds - and anti sieze compound will make you life better when you come back to do this in a few years. Pulling the boots can be a pain... but this bad-boy was the best $25 buck I've ever spent.... With this boot pliers, it was pretty painless.
Description:
Vinyl coated offset jaw tips will pull most domestic and import spark plug boots, including the back plugs on new-model Porsche and Mercedes Benz. Vinyl covered handles are cushioned for comfort.
Stock # SBP3
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