When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It looks like R9YCC are no longer available, only R9YC. If I have to go with something other than what is recommended, I might as well look at something like NGK. Rumor has it, X300 is sensitive to spark plug resistance. Please feel free to share the plugs that you had good luck with.
Also, are R12YC's only for supercharged cars? Any advantage to fitting those.
Any one have any experience or technical opinions on the 3 gap plugs ? Someone seems to have resolved his idle issue with them or if it may have been placing the O2 sensors connections correctly . Are the 3 prong a gimmick ?
The Champion RC12YC plugs are about $2 at any auto parts store or even Walmart, so it's hard for me to get too excited about putting a lot of additional research into spark plug choice. What's really humorous is that the RC12YC is normally found in the "garden tractor" section of the store, not automotive!
I just change them every year, especially since it is so easy to do on the AJ16
I *guess* so, as they don't say which Champion they are, but they are probably correct if they are being sold as a genuine Jaguar part. Not a bad price BTW.
Assuming you are inquiring about spark plugs for an X300 with the AJ16 engine, the Champion RC12YC plugs are $1.36 each at Rock Auto, plus shipping, but as Al says, you can find them locally for low prices, and the general consensus is that they are the best plug for an AJ16 and plenty of problems have been reported by owners who tried other plugs.
If you are asking about a different Jaguar model and engine, that will make a difference in the plug you should use.
Any one have any experience or technical opinions on the 3 gap plugs ? Someone seems to have resolved his idle issue with them or if it may have been placing the O2 sensors connections correctly . Are the 3 prong a gimmick ?
I haven't tried the 3-electrode plugs, but back in the '90s I tried the Bosch 4-electrode plugs in our '88 XJ40, and if anything, I felt the engine was slightly less responsive than with the stock Champions. This may have been my imagination, because based on the reports of others, I had expected some discernible improvement in engine performance but didn't notice any. Around that time, there were reports of the Bosch plugs having issues with the platinum tips falling off of their electrodes and rattling around in combustion chambers, so at the next oil change I switched back to Champions and never regretted it.
yes X300 AJ16 engine.
I sold my series III one month ago...
Originally Posted by Don B
Hi xjfourty,
Assuming you are inquiring about spark plugs for an X300 with the AJ16 engine, the Champion RC12YC plugs are $1.36 each at Rock Auto, plus shipping, but as Al says, you can find them locally for low prices, and the general consensus is that they are the best plug for an AJ16 and plenty of problems have been reported by owners who tried other plugs.
If you are asking about a different Jaguar model and engine, that will make a difference in the plug you should use.
Adding to Lady P. comments I had bought the recommended spark plug and my car ran like $#!+. I tried 3 different branded spark plug, made sure they were correctly gapped with no luck.. I purchased the 3 prong plugs and ran beautifully. Now my problem may be unique, however the O2 sensor issue was later down the road when I cleaned them and connected them to wrong harness. Anyways I plan on trying different plugs later down the road and see if there is a difference.
Which spark plugs should I use for XJ6 X300?
