30k Mile: Replace Spark Plugs


Replace Spark Plugs

Tools needed:

5mm hex key -- I highly recommend getting 5mm hexes with a 3/8" drive ratchet. The space to access the bolts is confining and can be time consuming without a ratchet.
Standard 5/8" spark plug socket
4" or 6" socket extension
Torque wrench capable of measuring 22 ft-lb

Parts needed:

6 sparkplugs. I got the ones Porsche sells, just because I'm that way. I'm sure that others do just as well. I paid $8.55 each

Procedure:

This is much easier than it looks. One thing to be cautious about, so I'm told, is the tube that the spark plug goes down can be dislodged in some way that can cause oil leaks. I didn't note anything that I could have done that might have caused this to happen, but the local dealership says it's quite common.

There are three spark plugs on each side of the engine, and they are accessible easily enough if the car is on a lift or jackstands and the rear wheels removed.

First let me describe how the plugs and coils are laid out. In each cylinder is one spark plug, as is common, and each plug has a coil which energizes the plug on command. So to replace the plug you have to remove the coils first.

Let's look at the parts. Here's the spark plugs.

P0001321.png

Yeah, I'm a terrible photographer. My point was that the plugs that came in my second replacement engine had two prongs and the new plugs from Porsche had four prongs. Also, note the amount of fouling on the plugs. It's dark, and due for replacement, but not really that bad that I would replace them earlier.

Here's what a coil looks like when it's removed.

P0001320.png

The coil slides down into the spark plug tube. Note the three seals along the shaft, make sure they're in good condition.

Okay, so here's what they look like installed.

 P0001318.png

To remove the coils, I suggest this sequence of events:

First pull the boot back from the cable. This isn't necessary, but will make it slightly easier to install it, in my opinion. Just slide it back about an inch.
Second, squeeze the cable connector and disconnect it from the coil.
Now, using a 5mm hex key, remove the two bolts holding the coil to the engine block.
Finally, and carefully, pull the coil from the spark plug tube.

Use the socket extension and the spark plug socket to remove the spark plug. Install a new plug and torque to 22 ft-lb. I've never used anti-seize on spark plugs before and I've never had one stick. The workshop manual makes no mention of using anti-seize, but many people have related horror stories about the ramifications of getting a plug stuck in the engine. I suspect using the proper torque prevents that, but I'm not sure.

After the plug is torqued in, slide the coil into the tube and bolt it to the engine with the 5mm hex bolts.

Plug the connector onto the coil. If the boot is not slid back, the connector will not fully engage. You should hear/feel a distinct click when plugging in the cable. Once the cable in connected, slide the boot back into position to cover the connector.

Do this with all six cylinders. 


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