matts6887

How can i tell if and when it is time to change the sparks on my 99 300; and how hard is it for a novice to do on their own such as myself; and is there a link to the steps involved with pics somewhere in these forums? thanks matt

fastnoypi

Don't quote me but i think plugs are to be changed at 100k miles. You can verify in your manual or calling your local Lexus dealer. The factory uses irridium plugs that can last up to 150k miles.


Here is the DIY provided by Lexmex https://www.clublexus.com/forums/rx-...-patience.html

His method is to change the plugs while leaving the intake manifold on.

Since you have an early RX, it may be worthwhile for peace of mind to check out your rear valve cover for sludge and replace your rear plugs the factory way by removing the intake manifold.

There is a DIY somewhere in the forum. Most of the tips i've found in this thread. https://www.clublexus.com/forums/rx-...lve-cover.html

JAB

Neither of these jobs is a DIY for someone who labels themself a 'novice.'

matts6887

Well; I do know plenty about cars as Ive been a car nut all my life so Ive studied all the brands out there and know quite a bit. I think with proper step by step instructions; and pics; if i had to i could do it myself. Especially because I am all for trying to save myself $ in particular because i usually dont have the funds to get it done at a local shop so to do that i would have to get help financially from a outside source.

matts6887

fastnoypi; As far as the valve covers go; yea Ive read several threads about taking the valve covers off and checking for oil sludge. Not sure if my 99 has the original style it came with from the factory or the new one; but i am guessing since its the first year of the rx; then im sure it has the original style valve cover unless one of the previous owner(s) either changed it out themselves or had a local shop do it. As far as determining whether or not that needs to be changed out for the newer design; I will keep checking the oil level every so often to make sure im not either burning any excess or having it be drawn into the intake or something else like that. But so far; so good(knock on wood) no cel's; no problems whatsoever with this 99.

matts6887

fast; I thought one is suppose to use denso plugs that I have read about in several threads? Or is denso the brand name and irridium the type of plug(s)?

fastnoypi

matt,
If the previous owners of your RX did alot of highway driving and typically longer commutes you shouldn't be worried about the sludge. Maybe even more so in the southwest, but smart to keep an eye on it. We have been noticing a pattern of oil drinking in early year RX's but i haven't been keeping track of region.
I suspect the thin baffle design in the early RX valve covers sludged easier in short commutes. Whipped up oil in cooler weather and short commutes, the oil is quite viscous and doesn't get a chance to drain from the baffles and traps the moisture from the blowby.

You can use Denso or NGK plugs, they are brands. Iridium is an element but a platinum-iridium alloy is actually used as harder material in plugs for longevity.

As long as you use the factory specified heat range , you can't go wrong with either.
fwiw, i am going to be installing Denso SK20R11's in my RX this weekend . I found a good deal on ebay for the set of 6.

AnthonyMtz

I got a set on Ngk Iridium plugs, got a great deal 38.00$ for a set of 6 I haven't got them yet but alot of people said they are just as good or better than denso, I heard salim say something about denso not being genuine parts and having other manufacturers making them and not being denso parts but I'm not sure

tllee

Follow the Lexmex instruction carefully, make sure you fully understand what he's talking about, then open your hood to match the pictures which he show on the threads. If you have any doubt , don't start your job, after any ignition part removed, you won't be able to start your car if you can't put it back. Keep those in mind and you will be fine.
** As soon as you encounter any difficulty, just calm down, don't rush it with any "brutal force". I saw a couple of guys who broke the spark plug and take days to resolve it.

thomas1

By the way the plugs are good for an easy 120k miles before change....

artbuc

Not even broken in at 120k. Only reason to change before 200k is to prevent threads from welding to the engine. Pull them out, dab a little anti-seize on the threads and re-install.

matts6887

Thanks for all the helpful info here guys. I am probably just gonna wait til further on down the road to change them because for right now my 300 is running excellent. No bogging or hesitation or anything of that sort. So Im thinking they were changed by one of the previous owners who either did it themselves or had it done by a local shop. But i will definitely keep this thread with the links to the pics handy if i feel I get to a point where i need to get new ones in there.

matts6887

other than mileage; how can i tell when its probably time for me to change out the plugs in my rx 300? Are there any warning signs per say such as being boggy, hesitation etc?

DewHawk

I changed my plugs at approximately 138,000 miles primarily because I thought it might improve performance. Really have not experienced any improvement, but certainly does not hurt.

I followed the aforementioned DIY and really did not have any problems.

hypervish

Matt, I suggest saving your money for a timing belt rather than "wasting" it on rear valve covers, spark plugs, etc.