roadfrog

My 08 was due for new spark plugs and after a search here at LS, I was unable to find anything showing a DIY. Nothing on Youtube or the internet either.

Hopefully this will help some of you out.

On a side note, I also took a minute to clean the MAF sensors.

Also, if you are anywhere near due for replacement of the two engine air filters, now would be a good time to do that while you already have all the shrouding off and the filter boxes out.

I decided on a set of Denso Iridium Long Life which are OEM and got them on Ebay for 101 dollars with free shipping. Part # is FK20HBR11 also known as part# 3473.

Total time to do this job is about two hours taking your time. No special tools are required, but you will need the following basic tools:

Spark Plug Socket
10mm deep socket and a 10mm wrench
Various socket extensions and flex adapter
High heat anti-seize compound (for the spark plug threads)
Pry Bar or crow bar (or any stout bar to push the engine a fraction of an inch from fender well)
MAF sensor cleaner (should you choose to clean them)
Flexible (preferably) magnet wand to pull out the plugs or anything else that drops into the spark plug chambers.........

So, lets get started!

Here are the plugs I used:






As mentioned above, they are Denso Iridium Long Life and our cars come from the factory equipped with these.

These plugs come pre-gapped from the factory, but it's always good to make sure. They need to be gapped to about .040 as seen here:




The first step is to remove all the engine bay cladding. All of the retainers are easy to remove. Just push in the little nipple in the center of the retainer and then pop it off. As for the silver engine cover, it just pulls up with a firm pull - no retainers or screws.




Next is to remove the filter boxes. This is done by loosening the duct work, removing the sensor clips and filters. Then, as seen in the pic, two nuts are removed. Then, just another firm upwards pull to disengage the clips underneath. The MAF sensors are screwed into the ductwork, so if you choose to clean them, you may as well remove them now... It's very easy.[img]




A little blurry, but this is what you have when everything is removed:




To get access to the plug closest to the firewall, you will need to remove the battery. It's easy to do and really, the only tough part is actually getting the heavy battery out of the engine bay. Simply loosen the terminals and pull them off. Then remove the nut holding down the top bracket holding the battery down. When you pull the battery out of the car, you have access to the battery box which has three 10mm bolts at the bottom. Once removed, the box just pulls out and gives you all the access you need to that rear-most coil pack and plug.[img]





To get access to the drivers side plug closest to the firewall, you will need to loosen all the associated nuts and bolts holding the Ignition module. Again, not a big deal....all 10mm nuts and bolts and easy to remove and access:








Now we're ready to remove the coil packs and plugs. There is a 10mm bolt securing the pack to the valve covers. Simply remove and then pull out the coil pack and set aside. NOTE: there are a few packs that are not easy to remove unless you wedge a pry bar between the engine and fender well and just pry a tad. We're talking just a fraction of an inch. Very tight tolerances in there. Again, just a very little bit of a pry. Perhaps some of you won't have this issue, but I know another member here at CL had to do the same thing:




NEW INFO: Recently it was noted that another option to using a pry bar, is to simply remove the rubber gasket surrounding the coil packs. This allows just enough room to get the coil pack out easier. To remove the gasket, there are slots in them that allow to insert a screwdriver and pry it off. [img]


When you remove the plug, you will require various extensions and flex sockets according to whichever cylinder you're working on. This is where a magnet want is handy....or a long set of pliers.

Here is a view of the old plugs next to the new. Don't fret about the wet look on the plug, it's just gasoline. I had only started my car briefly to move it in the driveway, and the fuel had not burnt off.[img]




When installing the new plugs, be sure to apply a bit of anti-seize compound to the threads. Not only will it allow for easier threading into the engine, it will also facilitate easier removal of the plug in the future and reduce the chance of breaking a plug in the cylinder. NOT GOOD!

Torque spec for the plugs is about 13 lbs/ft.

Then, just reinsert the coil pack and secure it with the 10 mm bolt removed earlier. Just snug! Don't over tighten - there's no need and you don't want to crack the pack.

Here's a pic of the drivers side MAF sensor:[img]






Two screws hold it to the ductwork. Simply pull it out and you'll see some fine tungsten wire inside the sensor. A liberal spray of this will clean it:




Once everything is done, it's a matter of just reinstalling all the engine bay cladding, battery, and filters.

So how does it perform now with the new plugs? To be honest, no difference, except maybe a bit smoother off the line. More responsive maybe? BUT that may be due to the MAF cleaning. I know on the BMW 745's, cleaning the MAF seemed to make a big improvement.

Hopefully, I didn't miss anything. I'll be happy to answer any questions or concerns you have. I'm on this site all the time! LOL

Nospinzone

Fantastic job! I'll leave it to Tee to put this in the DIY sticky.

I bet it took longer to get this thread up than it took you to do the job.

Hmmmm, the last pic was there and now it is missing.

Never mind, now its there!

Tee

I agree 100%! Thank you Roadfrog for this contribution , It's been added to the FAQ sticky under Mechanical Engine .

jiceoo

Thank You excellent work

roadfrog

My pleasure folks.... I'm just glad I finally figured out how to post from Photobucket!

Yeah.....about twice as long and three times as frustrating! LOL

Actually, that last pic can be deleted.... It's redundant. Not sure how it got there.

More to come. Next up is a DIY on front rotors. Then the revised 2013 fins for the wind noise remedy.

hfahmy

Great post!!! Quick question: when you removed the coil gasket, did u see oil at the bottom of the gasket itself? I am talking about the gasket that goes around the spark plug cylinder. I do not mean oil in the spark plug cylinder itself, just at the bottom of the gasket around it.

roadfrog

Negative. Bone dry. If you have oil there, you may have a valve cover gasket leak.

hfahmy

Thanks for quick response!! Just to confirm. Did u remove the coil gaskets to get the coils out? My coils were dry but I had to remove the gaskets that go inside the value head around they spark plug cylinder. This is what had oil in the bottom.

Lavrishevo

iTrader: (1)

New pugs should not be used with anti-seize. Lexus does not use it either. I just had my plugs done today by the dealer. I was also advised about using the grease by members but it is not advised by the manufacturers.

http://www.globaldenso.com/en/produc...ion/index.html

roadfrog

No. As you can see in the pic, the gasket comes off with the coil pack. The only thing you need to make sure, is that the gasket is properly seated against the coil before you put back on the valve cover and secure it.

On aluminum heads and using a dissimilar metal, you risk a plug seizing on the head. I had a very hard time removing a couple of the plugs and was convinced that the plug would snap in the cylinder head. You're not supposed to get any of the compound on the electrode, nor are you supposed to use a copious amount on the thread. Just enough to prevent cross-threading, and breakage when removing later on....especially when leaving them in for 60k plus miles.

I've never had an issue on my Beemers, Mustangs, trucks, race karts or anything else when using anti-seize. BUT if it concerns you...don't use it!

hfahmy

Thanks again!! See post https://www.clublexus.com/forums/ls4...ug-change.html

Step 14c of the instructions from lexus showed the removal of the spark plug/coil round gaskets to easy pulling out the coils. When I took the gaskets off there was a little bit of oil at the base. I thought these gaskets go inside the valve head cover???

roadfrog

Yes, I knew what you meant, but the gaskets are attached loosely to the coil pack and seal it up against the top of the valve cover, preventing dirt, water etc, from going down into the chamber. Sort of like a washer. They do not need to be pried off, unless they some how fused to the valve cover. Mine came right off without any resistance.

hfahmy

Mine has air suspension with the air control module on the top of the shocks and was almost impossible to get some of the coils out without taking out these gaskets. Once the gaskets were out, they allowed me to get the coils out at a much sharper angle without any resistance. Shall I assume now that having a little bit of oil on the bottom of these gaskets is normal since they are inside the valve cover assembly?

These gaskets are part #11193 in this diagram of the cylinder head http://lexus.sewellparts.com/oem-cat...S460-2008.html

roadfrog

Ahhh....OK...I see now, I thought you referring to the coil pack gaskets. I had no oil on those gaskets either. Everything was bone dry. If you have oil on and around those gaskets (which are built into the valve covers), perhaps some oil is seeping from inside the valve cover past those gaskets. Not a huge deal, but easy enough to replace.

chris07ls

How many miles on your old plugs?

I was going to do my first replacement at a 120K miles. My 2007 is at 102K miles, so I still have a year or so.
I noticed that RockAuto has these plugs at $11 apiece.