Changing Out Dirty Plugs
Spark plugs are one of those items that are constantly neglected in routine car care. Just like oil, they will need to be replaced. (Not as often, but the concept is the same) At what interval is mostly up to the user and is more often than not, application specific. We wound up replacing our plugs in the “Pre H2Oi prep” partly because there was slight dip at low RPMs and because we didn’t know the mileage of the old plugs. Now, normally when there is a slight dip at low RPMs, its best to isolate the problem with some testing, not throw parts at it. However we were pressed for time, and wanted to have fresh plugs at the very least. As it turns out, our coils and possibly coil pack are on their way out. (So look for a more detailed overview of the ignition system later) Back to the plugs. We chose to go with Bosch because they are a German brand, and a trusted name. Our plugs came pre-gapped, so that was a non-issue. The next step was to verify that gapping with our tool, and remove the old plugs. This was the worst part of this job, because everything was junked up from daily use. (So as you can see, this job is not a hard one) In order to get to our plugs on the 2.8 we had to remove the CAI out of the way, pull the engine covers and unscrew the coolant tank. (Do not disconnect it, you don’t have to in any way, shape or form) Next we pulled the coils, they are held in place by vacuum, so just wiggling them out was enough to break them loose. If your wires are old and/or brittle it’s a good idea to be careful when pulling them to prevent cracking. Also the order of the coils is important, if the coils are not placed back in the same firing order, you will have a hard time getting the car to run. In our case, the block had numbers on it. (It’s really clear what goes where, just make sure to double check) It was easy to get to the plugs after that with an extension bar and a deep 5/8s socket. This is the part worth the most care, unscrewing the plugs can be difficult and you must be gentle. If you strip the threads you are fu…, well you get the point. The same goes for reinstalling the new plugs, only use hand tools, and start the threads by hand. Make sure you don’t over tighten them and use a torque wrench to dial in the right numbers. After that it’s just the reassembly of everything and you are set. Dead plugs mean less Hp, bad gas millage and in extreme cases misfiring issues. Ours were not too great, and the difference was noticeable after installation of the new plugs. Something to think about next time you go to change your oil… As always don’t try this unless you got it bro. Happy wrenching.