I'm about to change the plugs on my Lexus RX300 (stealer and local independents want ~$1000, $250 of which is for the plugs!) I'm pretty handy with cars so I'm going to do them myself. I can get the plugs at local shops (Autozone, etc) and they are all the same price - $17.99 each (I guess that's the MSRP). Rock Auto has then for $6.50 each. I've never bought from Rock Auto before. Are they reliable for genuine parts (unlike Ebay and Amazon)?

 

I bought a lot from Rock Auto when had my RX300 and my two CTs after it and never an issue with them as far as the part is what it says.

 

They are a reliable parts source. You will get the genuine parts from them. I have been using Rock Auto parts for over 20 years and never had a problem.

 

Please read up the DIY on spark plug replacement.

You can cut down the amount of labor [unnecessary work] as the plugs can be removed and replaced by removing nothing. You just need the right tools and the ability to work in tight spaces [long arm length] and also the ability to work without looking.

Personally I buy the spark plugs from Lexus dealer. Take your vin and they will give you the right temperature plug. The dealer will charge you by the book hours at their high rates. The only thing I could not do was torque the plugs to spec.

Salim

 

What Salim said is something I also do. I buy my plugs at the dealer. The last time I did plugs myself I bought them at the Toyota Lexus dealer in West Kendall here in Miami, not cheap as I recall, but no issues with the plugs. I worry with plugs through mail about the gaps even if they have that nice plastic cover on the bottom.

Just note to be sure if you buy them online to check the gap.

Honestly, I don't even torque them to spec. I go until I feel the first tension with the wrench where it fights me back hard and then stop.

 

I'll check them when they come in. The iridiums are spec'd at 1mm (0.044") and are usually pretty darn close. They can't be adjusted if they aren't as the electrode will break if you try.

 

Pardon me for overstating the fact that Lexus/Toyota part number matches more than one manufacturer and your individual model may require certain temperature [hotter/cooler] spark plugs. OEM [based on vin] will call out for a specific temperature. As the vehicle ages, one needs to examine the plugs that come out and make adjustment to get optimum performance.

So NGK iridium for first gen RX, narrows down the scope but needs additional specification.

Salim

 

Yes, of course. The correct plug for the 1999-2003 RX300 is the NGK 4589 (IFR6T-11) "laser iridium" spark plug.

 

Got the plugs from Rock Auto in the mail and installed them this morning. I don't think I'll be doing that ever again!
The old ones looked fine after 130,000 miles. Sheesh, did I need to change them???

 

Replacing plugs at 110K miles is a controversial issue [just like transmission fluid change interval]. ... Members please leave transmission fluid change interval discussion for other thread(s).

Manufacturers come up with a list of items that are included in preventive maintenance [oils, plugs, belts]. Once an item is selected then the interval needs to be determined. Generally they specify age or milage [We all know the milage is travel distance while the wear is based on rotation of engine]. Commercial machines have a run time on engines. At the end as an owner, you have to decide, if you want to adhere to the manufacturer's spec or come up with your own. For spark plugs, personally I think the 110K is the right number. You do this change once and the vehicle is good for 220K miles. One can postpone till the failure actually happens. Changing on specified time ensures proper combustion [for some Lexus engines, Lexus has 60k miles for plug replacement to meet emission standards.

Personal experience: I did not change my plugs at 110K miles. At about 112K miles, I got a sustained misfire on one plug. Changed them all and very soon a coil pack went out. I replaced the plugs second time at 220k miles.

Salim

PS: Not many folks remember tune up needed every 10K miles, then 25k miles. In those tune up was plugs and wires along with other things. 110k is very infrequent.

 

Ha! Remember that well. every 10,000 miles needed plugs, points, valve adjustment, on my 1966 Ford Cortina. Cost £25 back in the day - that would be ~£250 in todays money. Try getting all that done today for that much!!! I remember tires, brakes, exhaust systems lasted 20,000 miles - cars today are so much more reliable and durable, just as well given the cost of maintenance and repairs!!!

 

Here are the old plugs. Gap may be a little wider than the new replacements but it's hard to tell for sure. The car was running fine.

 

newer rxs and gs have a 60k plug interval. Its interesting to say the least

 

Yes. If you look at the small print, it's to "maintain the emissions warranty". In other words, they're covering their rear against the Govt/State-mandated emissions standards!