mikey00

The 2001 RX owners manual lists Denso SK20R11 for the standard replacement plug. The Denso website along with many dealers list the K20R-U11 as the OEM plug with the SK20R11 listed as a long life plug and the IK20 listed as a better performance plug. I know all will work but can anyone confirm what plug number is in the engine from the factory. I now have 125K on my original plugs and have been pleased with their performance and life. When I do the switch I would like to use the exact ones even if another number claims longer life, better performance, better econmy,etc.

Lexmex

Straight out of the service manual, IG-3 is the page,

Recommended spark plug:

Denso SK20R11
NGK IFR6A11

I have had this manual since 2002.

mikey00

My service manual says the same thing. So does my owners manual. This is the recommended replacement plug but can anyone verify what is actually in the engine. I suspect the Denso site may be correct but have not had the time to pull a plug.

Lexmex

Well, I had another friend confirm that their 2003 service manual showed the same thing as above. Not sure you will really know unless you pull the plug.

salimshah

Once the manufacturer recommends certain makes and types, during manufacturing they can use either. It all depends what they have in stock. You can only be sure once you pull them out.

I would suggest to get NGK irridiums ... pre_gapped and long(er) life. 100k should not be a problem.

Remember to put anti-sieze and finger tight all the way and use the torque wrench at the end.

Salim

mikey00

Lexmex: I have a PDF of the 03 service manual as well and it does list the SK20R11 as replacement plug. The key word here is "replacement". I still think the Denso site might be right and the RX gets a set of K20R-U11 at manufacture. Anyone change your own plugs and remember what came out?

Salim: I am guessing you have not changed your plugs yet or if you have, you have not done DIY. I haven't done mine yet, but from looking at all the how to posts it looks like your torque wrench suggestion is impossible on the rear plugs or everyone just decided to skip it. I also don't understand your recommendation of the NGKs for "longer life, 100K should not be a problem". The Densos that came in the RX are good for 120K by the specs and can actually last a lot longer and are also pre-gapped plus I already know their capabliities from the last 125K.

salimshah

Very perceptive mikey00. I just did my son's sc400 and even on v8 (not even transverse) I could not get the TW on the last plug. I did the feel method, ( use what ever fits ) on the accessible and go back and forth with TW on the ones you can.

These days you cant even see the plugs face with the block

Salim

sktn77a

iTrader: (2)

Ah, for the old days!

AMN

I have 110K miles on RX 300 2000 and wanted to be prepared. what socket size do I need for spark plugs? do they use metric or inch? can you recommend Harbor Freight tools?
thanks.

cha41ppy

If you purchase the NGK IX iridiums they are BKR6EIX-11 and should last 120,000. That's what I recently installed in my ES (same engine) and everything's been fine. At autozone they were 7.99 a piece, good deal if you ask me. The equivalent denso brand was 12.99 I believe at the least.

To AMN, I recommend you go to autozone and borrow a spark plug socket set for the weekend. You may also need additional extensions on top of that. The actual size of the socket is 5/8 I think, not positive? Also a magnetic extender is helpful with a flexible neck piece so that you can swivel it in and pull out the rear plugs especially. There is one that's fairly cheap at AZ made by a company called OEM. GL

Lexmex

https://www.clublexus.com/forums/sho...d.php?t=264967

trhs75

It is a standard 5/8" spark plug socket. The threads on this forum are indispensable. It was a challenge to replace the rear three, but you can do it. I changed mine for my daughter when we got her '99 at about 108K miles. Good luck!!

mikey00

I did my plugs yesterday and was able to verify the RX comes with Denso SK20R11 as stated in the RX manuals and not K20R-U11 as listed on the Denso website. I replaced with the same number. The plugs were in remarkably good clean condition for 125K. Even the gap was still tight. I bet they would have gone a lot longer.

willie83

What is the spark plug gap supposed to be for a '99 RX300? I have searched around and can't find the number.

salimshah

The plugs are pregapped. My understanding is that the gnd-tab would break if you try to adjust it. The plastic sleeve on the plug prevents any force on the tab as it is shipped.

Salim