amstel78

Apologies if this has been asked and answered, but a few searches in this section did not reveal much. I'm pulling all 12 plugs on the passenger side this weekend and replacing them with new NGK IFR6Q-G pieces and was wondering about the correct torque range when tightening down? I've heard 15-25 Nm or 11-18 ft. lbs of torque is required. Is that correct?

Additionally, I plan to put a little bit of anti-seize on each plug thread prior to installation unless otherwise told. I don't know if MB calls for clean threads or not, but in my experience, it's always good to add a tiny bit of anti-seize on plugs going into aluminum heads.

One last thing - when rotating the passenger side intercooler out of the way, I think I recall someone stating once to be very careful about a vacuum tube attachment on that side which could snap when moving the intercooler. I can't seem to find that thread now, so anyone who's done this before, grateful if you could share your experience working on the passenger side coil area.

FWIW, this is the MBworld thread I'll be referencing when tackling this job. The OP only mentions driver side while stating the passenger side is similar but slightly different in some aspects.

Many thanks in advance.

Plutoe

Post your VIN!!

amstel78

WDBNG79J56A477014

Not sure why a VIN is needed for spark plug torque range for an M275 TT but there you go.

E42AMG???

It usually says on the spark plug box if you bought them in 4 packs. I think it's 14-17 ft lbs for aluminum heads

amstel78

I received 6 4-pack boxes. None mention torque specs which makes sense because these plugs are for various engines.

E42AMG???

It's 18-21.6 ft lbs for that spark plug which has a 14 mm thread diameter on aluminum heads.

https://www.ngksparkplugs.com/about-ngk/tech-talk/spark-plug-installation

Plutoe

Forget about all the HS---the factory spec for the 275 engine is 25Nm repeat 25Nm

amstel78

25 NM? OK got it. Many thanks.

BTW, what's HS?

Welwynnick

The Mercedes Owner's Manual says 15 - 22 lb-ft (20 - 30 Nm).

Nick

Colin Frolick

On the plugs I've just snugged them up and given another ~1/2 turn to crush the metal gasket, per NGK recommendation. Use antiseize and don't overtighten.

https://www.ngk.com/learning-center/...orque-settings

"Without a Torque Wrench:

If a torque wrench is unavailable, finger tighten the spark plug, then use a plug wrench to tighten.

NGK -1/2-2/3 turn on plugs with a Gasket. 1/12-1/8 turn on plugs with a tapered seat."


In the pictures you can see the hose extending from the front corner of the passenger side intercooler. It connects to a pressure sensor. I just unbolt the sensor from the bracket, unclip the wire, and leave the rubber hose attached. I broke the nipple off the sensor once but thankfully was able to super glue it back on. Cheers

www.hal600.tumblr.com

amstel78

Thanks Colin.

Managed to get the passenger side coil pack out yesterday along with all 12 plugs. Discovered that the 4 plugs from cylinders 5 and 6 were oil fouled. Not sure what's going on there. Hopefully it's just a case of a bad coil pack and the plugs got fouled after some time. If not, perhaps a bad injector?

Anyway, I have a digital torque wrench and snugged all plugs down to 25 Nm as recommended. Normally I snug and do a half turn to tighten as well, but in this case, felt I should do everything by the book.

Going to reinstall everything tomorrow with a rebuilt coil pack from Clark over at v12icpack.

EDIT: About that vacuum tube and pressure sensor; I saw that the other day when I pulled the coil pack. Rather than unclip the sensor from its bracket, I just removed the two screws holding the bracket down next to the voltage regulator and the whole thing swung up out of the way.