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TennesseeZ4 09-20-2012 12:29 PM

Spark Plug Question Z4
Back in a BMW after a few years hiatus. Picked up a 2003 Z4 3.0 with 51,000 miles. The previous owner replaced the valve cover gasket, belts, and the tires were replaced with Bridgestone RF; the timing tensioner/belt was checked, and the engine oil changed.

The service records show a pretty good track record, but I am moving to flush the brake fluid and cooling system, as there is no record of that having been done. I investigated some independents here in Middle Tennessee, but will be using the local BMW dealer for the heavy lifting items.

Previously I had a 535i, loved the vehicle, sold it to go SCCA racing. Now I am back on the street side of the equation, and really enjoy the Z4 on the roads around Tennessee.

Just completed the top cleaning and restoration with the RaggTops products discussed in the forum, and got great results. But the top was not that dirty. This is a two owner car that has obviously been garage kept. Seals all look good, paint has a few minor scratches, but overall I give it an 8 on a 10 scale.

So far there are no signs of the steering issues that many people note, and the tires do provide a bit of a stiffer ride, but the grip is good.

So I look forward to sharing some ideas with you folks. And I'll start with the spark plugs. Do you have a recommended after market plug that you use? And should I be aware of any special tricks involved in changing out the ones on the 3.0?


rsutoratosu 09-20-2012 01:08 PM

I dont have but I been looking for the spark plug data for a while, the oem is the bosch 4 ground tip one with do not gap. I got the ngk iridium and gap on it is .043" gap #1208. For your year, off the NGK site, its 6418.

Some other people have used iridium without any issues. I doubt there are any issues.. ill be putting mine in after I finish up the baby room in the house..

rsutoratosu 09-20-2012 01:10 PM - I assume this is your year

Randy Forbes 09-20-2012 01:31 PM

I'm a big fan of NGK brand plugs, but I seriously doubt there is anything to be gained by switching to any "rare earth" materials; I would stick with their recomendation for the standard 4-electrode and be done with it. The choice is yours.

I try not to pull the plugs out of a stinking hot aluminum head unless I have to (for diagnostic purposes) better to let it cool down, stone cold would be my preference here.

BMW doesn't recommend using any type of anti-seize on the threads, but I've put too many dissimilar metals together in my time to pay heed to that! My thread lubricant of choice has always been Kopr-Shield (by Thomas & Betts, can always find it in any electrical supply houses) and I use it sparingly; just the thinnest smear on all but the bottom two threads.

ALWAYS thread the plugs in by hand, but I suspect you already knew that, as you sure don't want to be faced with the prospect of a cross-threaded one.

Beyond that, sounds like you've got yourself a nice car, and know what to do with it, congratulations! BTW, my wife drove a 535xi for a few years, and that car's capabilities always amazed me; many's the time I was *just driving it* through a series of freeway esses and upon looking down at the speedometer again, discoved I was exiting the turns at over 95 MPH, and having no feeling of going that fast, nor intending to!

Randy Forbes 09-20-2012 01:34 PM

Oh, and the torque value on the plugs is typically 23 to 25 Nm. The dealer sourced plugs will have the torque value on the end of the box.

TennesseeZ4 09-20-2012 02:40 PM

Thanks so much for the response. Definately will ensure that the heads are cool, and I am also a fan of never seize for plugs. Likely stay with the Bosch, but I have used NGK a bit in some ITA cars.

I do miss the 535i, there are still motor cycle guys in the North Georgia mountains that recall some guy in a big black BMW closing right up on their tires in the tight turns.

I'll let you know how the plug change goes! And I'm going to go with an upgraded air cleaner at the same time, likely a K&N.

Thanks! :drive:

rsutoratosu 09-20-2012 04:01 PM

I will let you guys know how I make out, I have a 07 n52 and recently starting to get lower mileage, going to pull the plug on a weekend and check the condition or swap to the ngk i bought

brock5ga 09-21-2012 07:11 PM

NGK O.E. Part Number for the 03 3.0 is BKR6EQUP. Recently purchased a set in stock at local Advance Auto for $8.99/plug. I'm with Randy on the copper coat. Keep a bottle of the 3M in the box. Just a dab on the threads. I've read a couple of articles on the anti-sieze affecting the conductivity, but I have never had a driveability issue on any vehicle I have used the anti-sieze on. My opinion is the benefits out weight the disadvantages, of which I have seen none.

kalali 09-22-2012 07:47 AM

I pulled the plugs for inspection in my '03 2.5i at 85K miles and they looked literally brand new. With only 51K miles I suggest you check them first before spending the $. YMMV

TennesseeZ4 10-29-2012 12:05 PM

Went back with the OEM plugs, and I am quite pleased with the results. After 52,000 miles and almost ten years of age, it was time for the old ones to go.

Great results from the dealer here in Nashville. Now when you press the 'sport' button, there is a great deal of sport that comes into play! Lovin' these fall afternoons! :drive:

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