williakz

Thanks to the great tips and pics from roadfrog and others, AND the powerful incentive of a $495 price tag at the dealer (even Pep Boys was $395), I took on the task of changing out my unit's spark plugs. By carefully (and easily) prying off the coil pack gaskets, all coil packs came right out into my hand. The plugs were a different story. A buddy of mine told me to warm up the engine (just warm, not hot) so the head would "release" the plugs. Unfortunately, it took me so long to pull the computer and brackets from the driver's side (I was going very slow and carefully) that the engine cooled off and the last few plugs were real beotches to get out (sounded like they cracked at first, then they screeched their way out). Put a little anti-seize on the new plugs for the next guy and torqued them down. Popped the coil packs (and gaskets) back in and reinstalled the computer, brackets, battery, and air boxes and all done. I used Denso Iridium TT (IKBH20TT) from Advance Auto online with in-store pickup ($40 for the set with a discount). I called it my $500 day.

Now that I know the ins and outs, I estimate I could do the entire job in less than 45 minutes. Where those pros get off estimating 2-1/2 hours is beyond me (and is pure B.S.!)

Nospinzone

Good job!

Did you have to pry the engine a little to get at one of the rear plugs?

johnnyg66

NIce job. But seems alittle early to do plugs on 2013. How many miles do you have?

dlbuckls10

Why are you changing the spark plugs?

Littleguy

I know that one of the rear coil packs on the passenger side was a ***** on mine, hahaha.

spmcg

Boredom results in many unnecessary oil changes, but spark plugs?

williakz

60,400 miles on the clock. Read the manual and weep, folks. These 100,000+ mile plugs MUST be changed every 60k miles in order to maintain the emissions warranty.

Engine prying is totally unnecessary. This vehicle represents the pinnacle of Japanese automotive engineering, not a basket case for shade tree mechanics endowed with more BFFI than brains. There are small recesses cast into the valve covers at 9, 12, and 3 o'clock around each coil pack gasket to allow you to EASILY pry up the gaskets with a flat blade screwdriver, as needed (they left out 6 o'clock since it would never be used). Once the gasket and coil pack together are pulled free of the valve cover, the coil pack EASILY comes the rest of the way out with room to spare. Same way back in. The strut towers in no way interfere with this procedure (as described, but not shown, in the service manual). All that is NOT to say you don't have to come up with some creative socket/ratchet/extension/swivel combinations to get the plugs out and to torque the new ones in.

roadfrog

Shall I remove my DIY post? I don't want to be known for posting a "BFFI shade tree mechanic with no brains. "

williakz

Dunno, you're not the one that used the 2x4, are you?

Hint: when you're taking a 2x4 or pry bar into the engine bay of a LS460, you need to check the manual because you're NOT on the right page...

roadfrog

I sure am. Lol. I then revised it to include the method you described.

williakz

I very much appreciated your exegesis on changing the spark plugs in the LS. Without it, I would never have attempted the operation on my own and would have ended up several hundred dollars poorer in the event. THANKS!

(I meant the gentle ribbing on your guys' engine prying as a reminder to others to RTFM when dealing with these marvelous machines, even on something so "simple" as a plug change.)

roadfrog

It's all good and I took your post in good fun. Did you notice any difference after changing the plugs?

williakz

Nah. Any difference I would have "noticed" would easily be explained by placebo effect. No misfire codes, so I'm good. Ever notice how much smoother (happier?) your whole car feels after an oil change? Even the steering feels more like butter...

The "old" plugs (Denso FK20HBR11 (3473)) are shown below (D=driver, P=passenger, 1=front, 4=rear). Close up is of D1 on the left, P1 on the right. Negative electrodes (at bottom of plug) feel pretty rough; a buddy says that's because they run the engine so lean.

mstritt

What is the difference between the "old" plugs (Denso FK20HBR11 (3473)) and the new ones you installed - Denso Iridium TT (IKBH20TT) ? The owner's manual calls for the FK20HBR11 plug.

williakz

From what I gather, the Denso 3473 Long Life plugs (OEM in LS460) were early iridiums, specifically designed for extra long life, but the vehicle's emissions warranty REQUIRES a spark plug change every 60k miles. The Denso 4705 Twin-Tips are newer plugs with equal or greater longevity as the 3473s, and they have an iridium center electrode diameter of .4mm whereas the older 3473s are at .55mm. Supposedly, smaller is better when it comes to spark plugs. Also, the TTs were what came up as recommended plugs for my car by the computers at third-party auto places (Pep Boys, etc.) Finally, they were half the price of the OEM 3473s, and I'm cheap. Other than the microscopic iridium electrode, I couldn't see any physical difference in the two plugs types. Both have the same multiple "prongs" to guard the spark (or whatever they do).

P.S. I took a lesson from my daughter's 2013 Hyundai Sonata Turbo (plugs need changed every 45k miles) on what Owner's Manuals call for. Original factory plugs were a Denso with 20 heat rating. Hyundai then went to a colder 22 Denso a couple years later. Today, they're supplying NGKs in current Sonata Turbos as well as using them for replacements in routine servicing of older models. The point is: things change.