[XutvJet]

Today I changed my orginal spark plugs on my 2016 M235 with 45k miles. The car has a Dinantronics Stage 2 piggyback, catted DP, AFE air filter, and M2 lower airbox. A decent amount needs to come off like the side cowl covers, the strut brace, engine insulation, O2 sensor bracket, and driver's side electrical box cover. I had those parts off in about 10 minutes. I used a thin wall magnetic spark plug socket, a 3/8" swivel joint' and a 10 inch socket extension.. The plugs were fairly tight, likely breaking through the gum that builds up on the threads of the plug near combustion side.

What was unnerving was how the plugs didn't thread out smoothly. Every single one had some on and off resistance as I threaded them out. At first touch, it felt like the start of crossthreading but then it would go away for a 3/4 of a turn. Every plug thread looked clean as did the threads in the head. The new plugs threaded in fairly smoothly. The plug bores were spotless.

I've worked on a lot of cars over the past 30 years I can't say I've felt plugs come out like this. I can't tell if it's the way the threads are cut or if it's the slight angle of the swivel causing some bind.

Do the plugs always feel like this coming out?

[pmcmtnbkr]

I just did the plugs in my M235 with 42,000 miles. I didnt notice anything like what you are describing. I did buy my thin wall socket w/6inch extension from FCP Euro the swivel on it is very smooth. The only unnerving thing for me was convincing myself to not put anti seize on the spark plug threads

[delvec03]

I've a similar experience to the OP. changed plugs 2 times now, both were not smooth.

[Poochie]

When you put the new plugs back in, did you use a torque wrench to tighten them?

[XutvJet]

Originally Posted by Poochie

When you put the new plugs back in, did you use a torque wrench to tighten them?

Nope. I'm not a fan of using them on plugs. I'm pretty good at gauging torque with a standard length 3/8" racket, especially sub 30 ft/lbs torque. 18 ft/lbs isn't much plus BMW doesn't use crush washers on the spark plugs which is nice.

I did make sure to work on the motor when it was stone cold. It's bad news bears if you replace the plugs on a hot motor and then torque them to spec. The reason being the head/plug bore is widened fractionally from the heat, thus torquing to 18 ft/lbs could mean something closer to 40 ft/lbs when it comes time to removing the plug. Always do plugs on a cold motor.