So it seems there's a lot of miss-conception about changing spark plugs on the HR16DE, I decided to get DIY and show a bit of the truth behind getting this done. It is not necessarily for everyone but should save a couple of hundred dollars from the dealer.
Since my car now is coming close to 128k it is well overdue for a tune-up and changing the spark plugs is a about a whole day's worth of work.
There's a few things required tho, first of all, a special 14mm thin walled socket that can fit inside the spark plug bore without interference and with a rubber holder on the inside. This is where the special tool is required, Snap-On sells it (part# S9714MK) it's not a cheap socket selling for about 50$. The savings come from doing the job yourself.
The rest of the tools required are basic set of 3/8 extensions and ratchets. 10mm sockets.
First miss-conception is that the owner requires to buy a brand new set of intake plenum gaskets, that is not true, they are re-usable in design and simply need to be cleaned.
So I went ahead and took apart the intake filter out.
I continued to disassemble the rest of the plenum assembly, there is a total 7 10mm bolts holding itself down to the cam cover.
At this point to remove the plenum I had to remove the entire front bumper, because the hood latch assembly wouldn't permit it's removal due to interference, this got quite labour intensive.
Moving forward, I removed the throttle body too, 4x 8mm bolts hold it down. Removing the engine coolant hoses are tricky but a must.
Take note, to get clearance to remove the plenum, I also had to remove the intake solenoid it's held down by a small 8mm screw. Some oil may drip.
Second miss-conception, OEM plugs being Iridium, well mine weren't, they were Platinum tip models. Part# starts with PL = Platinum
So talking spark plugs, the new ones I ordered for the the job are NGK Iridium IX, these are the top of the line models Part# LKAR6AIX-11, these have a stock heat rating of 6 (cold) 2-12 is the gauge from hot to cold plug. These cost from 12-15$ each
These plugs have fine iridium tip and platinum ark
Here's the plenum's re-usable gasket, it has tabs for easy removal, I suggest cleaning it before re-assembly.
There is also a re-usable O-ring gasket on the throttle body side.
So using the special socket to remove the old spark plugs, I found out the stock ones on my car were indeed Platinum types from NGK. It seems I was well overdue for changing them, here they are lined up from cylinder #1 to 4
It seems cylinder #3 was running rich due to it's darker color, something to investigate. When doing a tune-up this is the best way to see the condition of the internals of the engine and this is big preventive maintenance many skip over. This gave me a huge report on what is going on with my engine.
So I went ahead and changed all the spark plugs and I also swapped my used coil packs to some new ones I had lying around from the scrap.
At this point re-assembly was in order, I had an extra plenum so I decided it was a good time to swap it for this wrinkle finished model I made a few days prior.
I think the result looks quite professional, take note I also equipped it with a newer T/B all cleaned up for this tune up.
After doing it myself, it turned out not to be such a pain, but a lot of disassembly work before getting to the cam cover.