Here is the list and recommendation for the spark plug replacement that list in the Owner's Manual and Repair Manual for Lexus models and years.
ES300:
1990-1998 60,000 miles
1999 90,000 miles
2000 to date 120,000 miles
IS300:
2001 to date 120,000 miles
RX300:
1999 to date 90,000 miles
SC400/430
1992-1998 60,000 miles
1999 90,000 miles
2000 to date 120,000 miles
GS300/SC300
1993-2000 60,000 miles
2001 to date 120,000 miles
GS400/430
1998 60,000 miles
1999 90,000 miles
2000 to date 120,000 miles
LS400/430
1990-1998 60,000 miles
1999 90,000 miles
2000 to date 120,000 miles
LX470
1998 60,000 miles
1999 90,000 miles
2000 to date 120,000 miles
LX450
1996-1997 30,000 miles
I hope this will help some of you to make the decision on your services. We have a lot of discussion about this issue before and how the Lexus dealer charge you for certain services. This is just a guide line that Lexus recommended in the owner's manual, not madatory or anything.

 

Helllo,
I changed my spark plugs with the stock Iridium plug at 90,000 miles. Other than a little smoother idle, I noticed no appreciable change in the car overall.l Then I read this post that said 99 GS4 need spark plug change at 90,000, and the 2000 GS4 needed the change at 120,00 miles. What gives? Is there a difference in the engines? I am sure that I could have driven my spark plugs another 30,000 miles with no problem. I also noticed that the original plugs had the letter "P" on the terminal end of the plug, (where the coil connects to), yet none of the replacement plugs had this "P" mark on them.

It is beginning to make me wonder if other things could be stretched out as well. I am sure that I could have gone longer, but how long is safe? Any opinions? How long has anyone gone before changing the original timing belt?

I am waiting for one idler bearing, two "O" rings, and the tensioner from Carson Toyota before starting on my timing belt change. Wish me luck.
GSEREP1

 

I have put together a tutorial on how to replace your spark plugs and ignition wires for the LS: http://www.lexls.com/tuneup.html

 

THANKS for all the information. I have the same 1UZ-FE engine in a 99 GS4, so many parts of this are similar. I don't have spark plug wires, so my plug change ritual is much easier. I DO have to change my timing belt, since I have 90,000 miles now. I received all of my parts from Carson Toyota yesterday, so my weekend is definitely planned out now.

I have the factory shop manual, and although I have never done a belt on this engine, I have done many timing belts in the past. As long as I follow the instructions to the letter, I am sure it will come out alright. I may photograph the entire procedure and submit it as a DIY.

Thanks again for the info. My brother-in-law has a 1994 LS with this engine, so I will steer him to this page.

Respectfully,
GSEREP1

 

gserep, when you do your timing belt and water pump, please pay special attention on line up the timing mark before you loose the timing belt tensioner. The manaul will tell you to line it up at TDC and then move it up for another 30 degrees( I'm not sure). This is very important step.

 

For some reason which I have never been able to get a correct answer on. All Toyotas or lexus, have the letter p on the passenger side engine bank. Just checked my plugs on my 04 runner, same thing. My Rx, same thing. I remember when I worked for Toyota in the early 90's we had some cars come from the factory with one side Nippondenso and the other side NGK. We could never get a straight answer from our district rep as too why they did this.
I do know that they mark the original oil filter for warranty reasons. Gm spark plugs from the factory have white dots on the end of them.

 

Thanks so much for that bit of information. Changing this belt is different than any other I have done. Because the tensioner is on the outside of the engine, adjustment is different. I have a service manual, and it calls for the engine to be rotated 50 DEGREES, AFTER the engine is placed in top dead center...(AND ALL TIMING MARKS LINE UP ON THE CAMSHAFTS). This IS a very important step. Be sure to check the camshaft alignment. Remember, the crank turns twice, and the cam turns once, so make sure everything lines up. The imaginary line formed at the "0" mark on the crankshaft pulley should line up with the center of the bolt holding the right support bearing in place. (This is, of course only visible with the upper access cover removed, so that the bearing is visible.)

The tensioner unbolts from the bottom of the engine's timing gear case. This tensioner is a self-contained hydraulic unit..(it has a piston in a cylinder bore, and it is NOT fed by engine oil.. as many other tensioners are). As time goes by, it starts to wear out, and the belt will start to lose its' tension. So it makes sense to me to change this part when doing all other parts. I ordered and received all the parts from Carson Toyota, and I saved a TON of money. I am also replacing the two roller bearings, water pump, and thermostat.. The bearings were 40 to 45 dollars each, instead of $90.00 each at Lexus. It is a pretty straightforward procedure IF you have the book and follow it religiously. The rule is to never rotate the engine without the tensioner and belt installed. After the tensioner and new belt are installed, rotate the engine crankshaft 2 complete revolutions, and line up at "0" degrees. If the timing marks on BOTH cams line up EXACTLY, things are correct.... If NOT, something is wrong, and the cams will have to be retimed properly.

My original timing belt looks fine for the 90,000 miles on the engine, but when I removed the left side camshaft access cover, there was considerable rubber fragments from the belt insde the cover. My car runs so good normally, I am not willing to take a chance, and let that belt break before changing it. I am sure it will last longer, but just how long is the question. I bought this 99GS4 used at 78,000 miles, and I must say that I like to run higher rpms (without going into the red of course), and I know that higher rpms most certainly contributes to greater belt wear. When I start up the engine, I listen to it, and when it is warm and idling, I can faintly hear the timing belt whining. I take that as wear, and also as the belt being a bit loose from normal usage. NO ONE babies the 1UZ-FE engine all the time, so for added piece of mind, I will change all the internal parts of this system, even though I am sure everything will last longer. I have owned Toyotas for years, and there is always a large "fudge-factor" built in to their parts. However, this is much different from my old single cam 1.6L Toyota 4 cylinder engine in my Corolla.

The only question I have in the whole scenario is this: In the book it says that both left and right camshaft timing gears are to be removed and inspected. Then they are to be put back on just before the new belt is installed. I don't see any evidence of oil leakage from the seals behind the gearing, and I see no need to remove the gears, just to put them back on again. I wonder if the dealers remove these cam gears, or just go on and install the new belt? I will obviously inspect the teeth for wear, and the belt for signs of being nicked by the gears. If I don't see anything abnormal, I see no need to remove and retorque these camshaft gears. They also suggest using a gear puller and removing the crankshaft gear as well. In your experience, do I need to take these parts off just to reinstall them?

Thanks VVT-i for all of your knowledge. I have 33 years of engine experience, both commercially and militarily on government equipment, but I still humbly bow to your extensive Lexus experience.

GSEREP1

 

My 2002 RX300 maintenance seems to indicate spark plug change at 120,000 miles, not 90,000. Which is correct?

 

VVT-i, this is a great thread for those who need some general info about when to replace our spark plugs. I wanted to suggest that perhaps if possible you could modify it so the owners know if they should use platinum or iridium plugs (what the car originally was equipped with from the factory as a guide & suggestion to replace them with ). Some have had questions when it came to what to replace them with & who is the plug maker: IE Denso, NGK etc. My owners manual as an example does not state if the plugs are iridium or platinum (I knew from experence that because of the vvt-i on my 01 ES that it takes iridium Denso or NGK are fine). Just a suggestion is all, as most of us would probobly want to replace our plugs with what Lexus recommends as opposed to "just any old plug" from Walmart or something.

 

Write up on SC300 --> Spark plug change, rough idle fix and cleaning engine
http://www.cardomain.com/memberpage/549510/2

Hope this would help

 

My friend helped me change out the spark plugs in my '01 ES, mileage at 88,280 miles. It took about 45 min to an hour. The old factory plugs were the NGK brand, and the new ones are the Denso Iridium IK-20 plugs ($13 per plug at Autozone). The front ones were really easy to change since they were underneath the engine cover, but the rear ones were a bit tricky. It IS possible to do the rear ones without removing the throttle body, as long as you have small hands, and we did that (including a couple extensions and a flexible one).

Hope this info helps out for any of the ES owners wishing to replace their spark plugs

 

Hi VVT-i,

This is a great thread and contribution to our knowledge base. You da man! Please keep it up.

George

 

The owners manual for the GX470/4runner V8 shows 2 plugs,

Denso - SK20R11 - Iridium plug
NGK - lFR6A11 - V power

The Iridium Plug is installed at the factory on both the V8 4runner and the GX470, this provides the 120K mile change interval. I don't understand why anyone would replace the iridium plug with the V power?

 

where is the write up on the sc400?

CEO

 

I KNOW HUH....THEY ALWAYS FORGET ABOUT US....HEHE