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Which coil packs are Good only Bosch or???Or just replace boots?
THANKS in ADVANCE!!!! I was very careful removing coil connectors and sparkplugs with you guys help.However the plastic boot guards had small cracks. My question is this Its only about an hour and half job to replace coils and plugs, air filter. WHICH REPLACEMENT COILS or should I just replace the lower shells, or order a set of Bosch coils? Or any other aftermarket that are quality? However careful I was the sparkplug boots were impossible to remove without cracking plastic guard over rubber boot.( I am mechanic now by trade with 50+ yrs exp. I have never seen design such as this, I do sea doo, Yamaha, Kawasaki,,and boats with gm blocks, none are this much of a pain. LOL) The merc. has tons of room compared to them. PLEASE DONT GET ME WRONG I LOVE WIFES MERC.its a awesome ride.Thanks and have a blessed evening!!
I will give you a tip on how to remove the COP.
I have replaced my spark plugs twice and mess with COP & plugs removal more than 10 times for experimental works and intake valve cleaning where boroscope is needed, so I can share the tip.
First you must verify which COP you are using, as the boots are not the same.
Hence make it a habit to post your engine model for parts accuracy sake
If your engine is M276 https://webautocats.com/epc/mercedes...asis=212059D04
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You need this kind of plier for ease of work.
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Secondly, the pull out direction must match the plug's boot straight section, as the plug hole direction is not straight down for M276, it is angled.
If few years have passed since last COP removal and not using dielectric grease upon installation, yes it is more difficult.
However, the key is that plier and where to clamp the plier at.
The boot is a mix of plastic tube and rubber tube.....if on my M276 3.0 Turbo.
Thankds for all the tips , I do use angled plug boot pliers, but The plastic cover on boot gets small cracks when removing them. and the boots were on tight with no grease inside!! I have learned how to remove the coil connectors as easily as possible. I bought car as a certified mercedes from dealer with full service records. However after changing the 3 on air filter side, I found there was no dielectric grease on plug boots or between plastic or on coil plugs.. I removed connectors and pulled out the same angle as sparkplug, They were still so tight on plugs that no way to remove without getting rough. Have you just replaced the plastic shell, or the complete coil. I know mercedes says no grease on 276 engines sparkplug boots but I did use some and smeared it in a fine coat around inside of boot ,but not on metal contact where it touches spark plug tip. The only thing that had small cracks was the outside case around the boot.I was able to fix small cracks so wife can drive car ,but I want to replace properly..I am a mechanic by trade since 93 and have over 50+ yrs building race bikes and race cars so The second time around it wont take me maybe hour or hour and half to replace boots. I just am contemplating replacing just plastic as boots seem fine, and car is running great. The only reason I replaced plugs as they were still in spec. But I have found if you leave plugs in for more than 5 or 6 yrs the bottom 3 threads on plugs corrode and can damage threads in head. Thanks for all your help !!! Yes you are correct it is 276 engine however I have seen a couple different brands of coils, I hate to replace all coils as they are fine but mercedes recomends replacing them Thanks again oh car has 80k on it.
Last edited by mrjetskey; 11-17-2023 at 03:58 PM.
Reason: miss spelling
Now that you discussed COP rubber boot, it reminds me that I need to replaced them next year for my 10 year refurbishment program. Thank u.
These rubber insulation value for our approx 30Kv COP will drop as the rubber age, so I choose 10 years.
I agree with you that spark plugs should not be kept untouched too long, I too worry the thread will seize.
ALU cylinder head and steel s.park male thread is not a good friend galvanic-ally.
My first spark plug replacement was at 10,000KM but 4 years. 2nd one was at approx 30,000KM ( still so good the tip ) and 3 years of use.
MB WIS has allowance for di-electric grease on spark plug boots, as long as it is the part where boot kiss the ceramic of the s.plugs and not the electrical contact.
However, it is probably not heat resistance enough at 205 Celsius decomposition temperature and basically almost no trace of it after 2-3 years at the boot.
Its easier to unplug the boot....yes... but no more gooey trace of it to be super slippery like when first applied.
Unlike the anti-seize which has much higher temperature specification, on my brake rotor to bearing hub contact, the anti seize stay good and "wet".
11-16-2023, 07:25 PM
