Dear Folks,
My Lexus GS300, 2006 is at 85k miles, currently it seems OK.
I did replaced O2 sensor month ago when I saw engine light on, my mechanics told me the O2 sensor was bad, before that the car consumed more fuel and weak. Since then it seens OK. I did change oil/and oil filter before having MOT few days ago. It passed MOT without any advisory.

However when I looked at the whole history of the car services (included from previous owners), it looked weird to me was that during previous years the car was yearly serviced by Lexus Dealers/Authorised Repairer, I could not find at anytime the spark plugs was changed. However also in the same service form, it was written as "Replace spark plugs every 60,000 miles (platinum/iridium)", and that box was marked black (i.e., not applicable to this service interval).

(1) My first question is should I replace spark plugs now? Are there any way to use OBD-II to check if the spark plugs need to be replaced? Did you change sparks plugs at 60k miles or just leave them alone?

(2) I also found two different types of spark plugs: 1- earthed and 3- earthed, which one is better? What should I should use if I need to replace the spark plugs? Do I need to replace all of 6 spark plugs? What is the OEM (original type) of the spark plug?
Many thanks in advance for your advice.

 

Buddy, LISTEN: does the car drive ok? Feel good?

Then back away from people telling you to spend money. They have their agenda, it’s not yours.

Back away from any urge, we will walk you through it. Besides a transmission drain/fill, check diffs, NO you do not need to be pushed and bullied into stuff. We’ll help you.

 

Personally if you have no record of them being changed and you haven't changed them then I'd do it/get it done. Car is clearly running OK but it's one more thing off the list. Yes, change all six and I believe the Lexus part number is 90919-01249 but you can give Lexus Parts Direct a call or speak to your local dealer.

https://lexuspartsdirect.co.uk/produ...park-plug-kit/

 

PN listed by rich1068 is correct for the 2007 GS350 and later. Best confirm their fit for a 2006 GS300. Use only OEM (Lexus, Toyota or Denso) spark plugs from a known source (dealer). Too many Chinese fakes out there that will eventually cause your car to run worse than if you left the originals in.

I changed my plugs at 100k miles (10 years) but the car was running well at that time. Your plugs are probably original so after 18 years, I'd swap them out.

Good luck.

 

Actually nobody pushed me to change. However I am worried that the spark plugs could somehow cause the O2 sensor issue (which I had paid my mechanics £622 for it, he also advised me other bad things so now become my ex mechanics). Regarding transmission and diffs, I also could not found any time they were changed during services over years. When would I should change that too?

 

Threw me a bit with the part number but LPD seem to list the same plug for most models of that era.

https://lexuspartsdirect.co.uk/?s=90...ct&dgwt_wcas=1

LPD are actually Lexus Swindon so agreed, a call to them might be a good idea.

Should be all in your service book if you have one. If not and assuming it's the same as the one I have for my 450h then there's a pic of mine here https://www.clublexus.com/forums/hyb...intervals.html Looks like diff oil every 20k but no mention of the transmission as Lexus will say it's sealed for life. Plenty of info on here to change the fluid but that's up to you.

Where in the UK are you John? I know a great independent near Sheffield.

 

Many thanks for your reply. I lives in Merton area. I also shared one page from my car service book, you can see the item "Replace front rear differential oil (separate type)" is NA at 54962 miles. It was serviced by Lexus Dealers/Authorised Repairer. Do you think my car need to change differential fluid?

 

It would be a good idea if you don't know if it's been done.

You don't say how long you've had the car but you mention Lexus history which is a good thing but not the whole story. It's not unheard of for main dealers to miss or ignore items such as diff oil even though the book says it should be done. And it's basically a given that most independent garages will ignore that stuff unless specifically asked to carry out the work. Whenever I buy an older car, unless I know the previous owner or garage that looked after it personally, then I start with the assumption that nothing's ever been done properly and work my way through the service list changing consumables and fluids. It's worked out fine so far.

Hope this isn't breaking any rules but why not head over to https://www.lexusownersclub.co.uk/forum/ and ask there if anyone knows a Lexus specialist near you?