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Discussion Starter · #1 ·
Hi Guys! Since the manual says that the life of the plugs is 105k miles, I have planned to replace them around 100k. However, recently I read elsewhere that the plugs can deteriorate so much that replacing them around 80k can have significant impact on mpg (Not for MDX). So I begin to think whether I should do it ahead of the schedule as well. I am wondering whether anybody here has relevant experience to share? Thanks for the help.
 

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Yes and you should..... My Denso OEMs were in pretty rough shape at 73K..
Replaced them with NGK Laser Iridiums and been pretty good so far but I wont make those reach 100K either... 80K sounds like a good compromise.
 

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Discussion Starter · #3 ·
Ok. I see. Probably my weekend project then. Thanks a lot. I retorqued those plugs once before around 50k miles. It was pretty easy to reach all 6 plugs.
 

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I waited until the 105K service on my TSX and RDX (both due around the same time). I've noticed I got back lost HP, faster starts, little better throttle response, and back to normal mpgs. I just didn't notice the loss in performance until I put in the new plugs.

I decided to replace my MDX plugs at 75K to make sure I don't have the slow drip drip drip loss in performance over years. I am now close to my 105K service and it will save me a little $$ since the current plugs only have 25K on them.

NGK 5787 Spark Plug, Amazon, $11 each: https://www.amazon.com/NGK-ILZKR7B-...automotive&vehicleId=5&vehicleType=automotive
 

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Discussion Starter · #6 ·
I waited until the 105K service on my TSX and RDX (both due around the same time). I've noticed I got back lost HP, faster starts, little better throttle response, and back to normal mpgs. I just didn't notice the loss in performance until I put in the new plugs.

I decided to replace my MDX plugs at 75K to make sure I don't have the slow drip drip drip loss in performance over years. I am now close to my 105K service and it will save me a little $$ since the current plugs only have 25K on them.

NGK 5787 Spark Plug, Amazon, $11 each: https://www.amazon.com/NGK-ILZKR7B-...automotive&vehicleId=5&vehicleType=automotive
Thanks. I bought them long time ago at a good price. All six for $30, tax included.
 

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Discussion Starter · #7 ·
Agree that 60 to 75K is a good interval.
Mine is already about 89k. Sad. Probably have lost a lot of gas for nothing. Anyway, it is better than doing it 16k later. I read that you are a retired Honda Acura technician. That is great. Please feel free to share your insights whenever you have time. I guess a lot of guys here are more than happy to hear them.
 

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I would recommend it. Just did mine with 133k on my odo and they looked a little over do. I was lucky and had to replace both valve cover gaskets as the coils were soaked in oil. Took a few hours but not bad, had to remove the plenum to get to the rear valve cover bolts also.

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I waited until 100Kish and noticed no difference. Just another data point. It was the same with my old 03 and 99 RL.
 

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Hi Guys! Since the manual says that the life of the plugs is 105k miles, I have planned to replace them around 100k. However, recently I read elsewhere that the plugs can deteriorate so much that replacing them around 80k can have significant impact on mpg (Not for MDX). So I begin to think whether I should do it ahead of the schedule as well. I am wondering whether anybody here has relevant experience to share? Thanks for the help.
IMHO you really can't go wrong with either Denso or NGK spark plugs- and replacing them after 105k actually seems kind of belated to me!...I had mine replaced last year at around 82,000 miles and it took me alot of anal retentive research and a few arguments/debates on the thread below before I finally settled on the DENSO iridiums which have been holding up very well (call me crazy but i noticed immediate improvement with respect to overall engine response, performance, sound, fluidity etc. if any of that even makes sense?!! :laugh:

I did pay my local Acura stealership the labor fee to have the new spark plugs installed (no way in H. I was going to get this task done myself!)...they gave me back my old OEM spark plugs afterwards and they looked very crapped out/worn down.

http://www.mdxers.org/forums/74-sec...acura-mdx-spark-plug-replacement-inquiry.html
 

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IMHO you really can't go wrong with either Denso or NGK spark plugs- and replacing them after 105k actually seems kind of belated to me!...I had mine replaced last year at around 82,000 miles and it took me alot of anal retentive research and a few arguments/debates on the thread below before I finally settled on the DENSO iridiums which have been holding up very well (call me crazy but i noticed immediate improvement with respect to overall engine response, performance, sound, fluidity etc. if any of that even makes sense?!!

I did pay my local Acura stealership the labor fee to have the new spark plugs installed (no way in H. I was going to get this task done myself!)...they gave me back my old OEM spark plugs afterwards and they looked very crapped out/worn down.

http://www.mdxers.org/forums/74-sec...acura-mdx-spark-plug-replacement-inquiry.html
How much did the labor run you? Just curious I just did mine and have had friends ask me to do theirs.

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How much did the labor run you? Just curious I just did mine and have had friends ask me to do theirs.

Sent from my SM-G950U using Tapatalk
I think it was like $180?....I'm sure the stealership really 'stuck it too me' but I don't mind, those new spark plugs installed were definitely worth it! (as confirmed by the healthy engine rev/response, immediately noticeable upon first drive with the new one's installed...+ they're still holding up well/working like new + 1 year and about 15K miles later!)
 

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I think it was like $180?....I'm sure the stealership really 'stuck it too me' but I don't mind, those new spark plugs installed were definitely worth it! (as confirmed by the healthy engine rev/response, immediately noticeable upon first drive with the new one's installed...)
Not as much as I thought thanks for the reply!

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Discussion Starter · #15 ·
I looked up the specs of the plugs, NGK 6994 IZFR6K-11 Laser Iridium Plug

https://www.ngk.com/product.aspx?zpid=9848

The life expectancy is 80-100k and the torque spec is: Torque Specs: Cast Iron: 18-25.3 lb. ft. Aluminum: 18-21.6 lb. ft. But online discussion typically says it should be 13 lb ft. I just set it to 15 lb ft. IDK if this is the correct thing to do.

BTW, I recently looked up the Denso iridium plugs (twin tips) for my other cars. The Denso has iridium for both center electrode and ground. The NGK is only for center. The ground is platinum. However, the Denso's center electrode is only 0.4mm. The NGK is 0.6mm.
 

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Iridium is a very hard material but it isn´t a terribly good conductor...
Having both ends being Iridium will mean it will probably outlast the car but it would not be as efficient as Iridium + Platinum.

NGK Iridium IX for example is the "Performance Plug" and while it has a Iridium Tip the Ground is Nickel so it has Amazing Efficiency while lasting a reasonable time in High Stress use.

I would personally use Iridium IX but the MDX does not seem to have a fitting part..
(I use Iridium IX in my TL-S and they are the best plug I have ever used on it)
 

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Discussion Starter · #17 ·
All right! After watching the Patriot and Buccaneer game, I spent 2 hours to replace the plugs, take the car out for some test driving and a little grocery shopping. After I came back, it was exactly 12 AM. Glad that I did not delay it to the next day. The old plugs look very healthy. I tried to take pictures, but the lighting did not do justice to them. So I shall take some pictures tomorrow during day time.

I am also happy to notice that my odometer is actually at 88k miles, instead of 89k. I am very glad because I indeed noticed A BIG DIFFERENCE before and after the plug change. I can totally tell that the car now starts quicker, runs more smooth, and has more power. Seeing is believing. Currently the car's display shows that my average is 17.6 over about 8k miles of driving. This is pretty low, still reasonable b/c my wife is pretty much 80% driving around schools, shopping and in parking structure of her office. When we first got the car 11 years ago, she got 17.3. So probably have not waste too much gas.

Also I spend 2 hours b/c cylinder No. 3 is a b*&#^. I got all the other 5 plugs done in 30 minutes. But the last one is very annoying. I did use a lot of 3/8'' extensions and u-joints to get this one done. So be prepared if you want to try this.

Finally, I must recommend this tool to beginners.
https://www.amazon.com/GearWrench-80546-8-Inch-6-Inch-Swive/dp/B0014ZVSVK

It literally took away all the pains and hassles. Life is so much easier with this tool. The benefit to cost ratio is HUGE.

PS. I think I can tell the difference b/c J37 is a performance engine. I replaced the plugs on my ancient Camry with Denso twin tip iridium plugs not so long ago after 55k miles but 10 year. I couldn't tell any difference at all. That engine was designed 25 years ago, I guess any plug will be good enough for it.
 
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Discussion Starter · #18 ·
Here are the pictures. Any comment on the health of them?
 

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Yeah they look ready to be replaced, the tip looks more worn out that the ones I took out (Mine were 73K) so it makes sense. Did you compared them to the tip on the Laser Iridiums? I swear those had like hair thin Iridium Tips.

On another note my X spark plug replacement went smoother than my TL-S... The MDX does not need to have stuff replaced like my TL-S and #3 cyl was not difficult thanks to different sized extensions, Those proved useful when trying to avoid the heater tubes.. The only difficult thing was to extend my arms to reach the back plugs so I ended up leaning on top of the radiator cover which made it easier.

I am getting the parts to do the Valve Adjustment now and DAMN that is going to be interesting??
 

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Discussion Starter · #20 ·
I did not really compare ...

Which symptoms lead you to do the valve adjustment? Yours only have 100k miles, right? Isn't it too early. I always thought that is a job after 150k or 200k miles. But I am certainly very interested. Keep it up.
 
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