Monday, March 21, 2011

How to change spark plugs on 2003 Nissan Maxima?

This is complete guide:----------

Changing the spark plugs on a 2002-2003 Maxima is not something you should have to do until around 100,000 miles. The stock plugs are platinum tipped and should last a very long time. Replacement of the plugs is something that Nissan recommends you "see your dealer" to do. The reason is that in order to replace the 3 plugs in the rear cylinder bank, the intake manifold upper and lower collectors have to be completely removed from the vehicle. To do this requires skill beyond the average Sunday mechanic, since there are many vacuum, electrical and coolant lines that have to come off in order to perform the job.

I documented the entire process with pictures and text so that if there is anyone out there who wants to do the same, perhaps they will not be quite as intimidated as if they were going in cold. The job is not simple, and took me about 3.5 hours, but I did take a lunch break, and was also documenting the process with a digital camera.

Cost of the job was also not cheap - a set of 6 ignition coils from Courtesy Nissan cost me $333.48. The required gasket is another $18.40. The plugs themselves will run you $11.00 each. If all you really need to do is change your plugs, obviously you don't need to buy coils, so then all you would need would be 6 plugs and the gasket. Do the job yourself and you will save quite a fortune in labor, as this job performed by the dealer would be many hundreds of dollars.

Here is the nice clean engine bay before going in with the chainsaw. If you have a front strut brace, as I did, it is probably not necessary to remove it, but I did simply to make it a little easier to lift the collector out. It only takes a minute or two anyway.

Nissan Maxima Spark Plugs Replacement Procedure
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This pic still shows the strut brace in place (I removed it later). First step is to remove the 4 allen bolts securing the engine cover, and take it off.

Nissan Maxima Spark Plugs Replacement Procedure
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A view near the firewall. The test is if you can reach and loosen these two bolts then you can do the rest of the job. It requires a 12mm socket with a long handle.

Nissan Maxima Spark Plugs Replacement Procedure
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My method of doing this job will show you how it can be done without disconnecting so many vacuum lines, as I have seen others do. All you need to do is take a few parts off first so you can reach the bolts that attach the collector to the engine. Leave the electrical connector off, but put the valve back on.

Nissan Maxima Spark Plugs Replacement Procedure
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Same idea with the vacuum tank. Take it off only so you can reach the attachment bolts. Then put it, and the VIAS control solenoid valve back on.

Nissan Maxima Spark Plugs Replacement Procedure
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Once you get these 3 bolts, and 2 nuts off, you can go ahead and put the VIAS and vacuum tanks back on the collector.

Nissan Maxima Spark Plugs Replacement Procedure
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Don't take these off! No need to. You'll see why later.

Nissan Maxima Spark Plugs Replacement Procedure
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Two vacuum lines which need to come off. Slide the compression clamp down, and twist the hose off. Easy.

Nissan Maxima Spark Plugs Replacement Procedure
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These electrical connectors need to be popped off. Be careful you don't break them.

Nissan Maxima Spark Plugs Replacement Procedure
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You also have to release and then slide the lower half off their brass fitting, or you won't be able to lift the collector assembly off.

Nissan Maxima Spark Plugs Replacement Procedure
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Again, another picture before going in with the chainsaw.

Nissan Maxima Spark Plugs Replacement Procedure
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Loosen the screw holding the rubber connector to the intake. Leave the other side alone. It will stay.

Nissan Maxima Spark Plugs Replacement Procedure
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Unplug your "drive by wire" electrical connector, for the electronic throttle.

Nissan Maxima Spark Plugs Replacement Procedure
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Pop out the two plastic harness holders.

Nissan Maxima Spark Plugs Replacement Procedure
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Get the wire out of the way.

Nissan Maxima Spark Plugs Replacement Procedure
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Remove this plug, take the 10mm bolt out, then put the plug back in.

Nissan Maxima Spark Plugs Replacement Procedure
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Make room.....

Nissan Maxima Spark Plugs Replacement Procedure
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This was a tough picture to take. A little trick here - disconnect hoses 1 and 2 right at the area pointed to by the yellow line. Be prepared for a little bit of coolant to spill out when you disconnect hose #2.

Important - disconnect hose #3, not where you see the yellow line here, but at the other end of the hose. You will never in a million years reach this hose where the arrow is pointing, but you can reach it at the other end.

Slide the compression clamps down before you try to take these hoses off.

Nissan Maxima Spark Plugs Replacement Procedure
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Just another view at lines #1 and #2.

Nissan Maxima Spark Plugs Replacement Procedure
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Removing hose #1.

Nissan Maxima Spark Plugs Replacement Procedure
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After all of the hoses and electrical connectors come off, you can lift the entire intake collector assembly up and out. This is what the engine bay looks like with the collector assembly off.

Nissan Maxima Spark Plugs Replacement Procedure
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Another view of the engine bay.

Nissan Maxima Spark Plugs Replacement Procedure
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The collector assembly is rather large, but it is actually very light. I took the opportunity to clean mine up with some Gumout intake cleaner. Note that hose #3 is still attached to the collector!

Nissan Maxima Spark Plugs Replacement Procedure
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Note how all of the assemblies remain attached when the collector comes off.

Nissan Maxima Spark Plugs Replacement Procedure
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Here is a side view.

Nissan Maxima Spark Plugs Replacement Procedure
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The procedure to remove the coils is the same for the front bank as it is for the rear. Just take the 10mm bolt out, unplug the connector and pull it right out.

Nissan Maxima Spark Plugs Replacement Procedure
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This is what one coil looks like.

Nissan Maxima Spark Plugs Replacement Procedure
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Use a spark plug wrench to remove each plug.

Nissan Maxima Spark Plugs Replacement Procedure
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Nissan recommends you change this gasket any time the collector comes off. It is an expensive gasket, but why risk it? Buy a new one.

I do not show re-assembly here, but just follow these steps in reverse order. I hope I have de-mystified this process a little bit, and that you might be inspired to do this job yourself when the time comes. Good Luck, and you can do it.

Nissan Maxima Spark Plugs Replacement Procedure
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