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Old 04-10-2012, 07:53 PM   #85
Registered User
Join Date: Oct 2011
Location: Southern California
Posts: 247
My Ride: 2003 325i Sedan
So I changed my spark plugs

My car has 82k on it and man did it need it! BMW says to change spark plugs in 100k intervals but I recommend doing it in 60k intervals. I just got my car so I did not have it to change them at 60k. My car had NGK plugs in it, I went with the Bosch plugs, because they we're a bit cheaper and are very comparable to the NGK plugs. I dont have a supercharger or need anything fancy that is why I'm not as concerned. Plus We install NGK and Bosch plugs in all of our cars so Its no different than the dealer changing the plugs.

The Bosch Part Number is: FGR7DQP-6

I picked them up from my local Auto Zone cause they had them in stock, the same plugs you find on ECS Tuning:

I noticed immediatly after installing them that my fuel economy has improved, under same driving conditions. Its no surprise considering the way my old plugs looked!

I had a intermittent thermostat fault which would cause my car to run a little cooler, which in turn made it run a little richer, hence the darker plugs.

My old Spark Plugs after 82k!!

A comparison between the Bosch and the NGK Plugs, Very Similiar.

Not much to say about installing spark plugs. I know there are DIY's out there for it, so I didnt get to in to it but a few things to note are:

-How Tight?
Always remove and install plugs by hand tools ONLY, never use electric or air tools. Going to tight can damage the threads in your head, and also crack the porcelain of the spark plug. I believe spec for these plugs is 23nm or so. Think about how much leverage you are using. After the plug is hand tight, pull out a ratchet and slowely tighten the spark plug. You will be able to feel the crush washer of the spark plug compress and bottom out. Its tricky but this is a great skill for all techs. Learning how tight you are torquing things without a torque wrench, though it is never a replacement for a torque wrench, it is useful for less particular engine components ex. (Brackets, valve cover hardware, ect.) Once you feel the crush washer bottum out, give it a good snug. Thats alll you need.

Most people dont ever put anti-seize on their spark plug threads but it makes it easier to remove and install spark plugs without damaging the threads in the head as well as help you ACCURATELY torque them in. So I take a little general anti-seize and dab it on the threads making a little line down one side of the plug. As you thread the plug in, the anti-seize will make its way around the whole plug. Take care not to get any anti-seize near the electrodes or tip of the plug.

Well Thats all for now. Now I'm just waiting for the wheels and tires to come in.

Here's a little pic, I took today at work.

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