spark plugs

i have a w124 1990 300e and i want to change the plugs. have new plugs, the copper ones, and i would like to know how do it. is there any tricks, and can i do it myself?

thanks mike

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1990 300 e, 156k

[jeffsr]

Sure you can Mike. Best when engine is cool. Firmly grasp metal shield on each plug wire and gently twist and pull to remove them. Make sure you have the right size spark plug socket (should have a universal neck). Remove plugs, inspect same for abnormal conditions. Correctly gap new plugs (think it's about 35 thousanths) Install and torque to about 10-12 ft/lbs. Don't overtighten (aluminum head could strip threads). Replace plug wires. Drive away..

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Jeff L
1987 300e
1989 300e
1987 BMW 325

Jeffsr, u have answered alot of my questions, in other topics, i greatly appreciate that,

i feel kind of stupid, but how do i correctly cap the plugs and "Install and torque to about 10-12 ft/lbs"

thanks again

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1990 300 e, 156k

[jeffsr]

Oops, you gotta buy some tools mate!!. Spark plug gapping gauge and a basic set of metric sockets. Can be had at Auto Zone w/o breaking your bank. Check your owners manual for correct gap setting. Then stick the gauge between the center electrode and ground electrode and bend the ground out or tap it in 'till you have the right distance. Torque means buying a torque wrench. If you're going to work on your car at all, it pays to have a decent torque wrench (many aluminum parts) 3/8's or 1/2 inch drive OK. BTW, get yourself a service manual for your car, or a W124 CD from parts shop here (if you have a computer, of course.) Torqueing simply means setting the wrench to the specified value and tightening the part until the wrench indicates you've reached the set value. You will really enjoy working on your car and you will learn a lot about your car in the process. Get that manual. Stupidity is not related to inexperience or lack of knowledge. Asking questions removes you from the "stupid" category. I learn something every time I log on to this site. Donnie, Steve, Larry and all the others are really great. Keep coming and keep asking those questions. Everyone here will be more than happy to help. Maybe you'll teach me something as well. Good luck and happy "torqueing".

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Jeff L
1987 300e
1989 300e
1987 BMW 325

Just wanted to add a couple of points to jeffsr's advice. If you have access to an air compressor, you could blow some air around the base of the spark plug after you pull the plug wire off. This will get rid of the lose dirt around the base that may drop into your cylinder once you remove the old plug. Also, please use put a small amount of anti-seize lubricant on the threads of the new spark plug before you install it. This will prevent the plug from seizing in the cylinder head and will greatly ease the next plug change. Good luck.

[MikeTangas]

Mike,

To expound on jeffs description of "just the right distance", just the right distance is, well, sort of a felt thing, something that you'll come to know with experience. Whichever type of gap gauge you get, be it a gauge with flats, or sized loops, you'll look for the area of the flat, or individual loop, that is marked with the dimension you need. Slip the gauge between the electrode and ground. If you cannot slip it in, you'll need to open the gap, by bending the ground outward. Your gapping gauge should have a notch with which to bend the ground. If it goes in really easy and slops around you'll need to tighten the gap. Very gently tapping on a solid surface should do the trick, just check every tap or so.

Now for the "felt part. When the gap is right you should be able to insert the gauge, and as the gauge passes between the electrode and ground, you should feel the gauge just barely touching both points.



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Mike Tangas
73 280 SEL 4.5

thanks to everyone that responded. i fell much more confident about my car, my baby, lol. anyway, i will make every effort to follow your advice. thanks again

mike

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1990 300 e
clear corners
limo tint
2 10's

[jeffsr]

See Mike, it's easy to fall in love with a 300E. Take good care of it and it will love you back..Look at all the good stuff you found out in a few quick posts.

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Jeff L
1987 300e
1989 300e
1987 BMW 325