bizeau77

Hey guys, I'm about to change the spark plugs in my '99 GS300. It has 148,000 mi. on it and I doubt they've ever been changed. Should I also replace the wires since I'll already be in there? Should I consider replacing anything else associated as well? I usually go with OEM parts unless you guys recommend another brand. Thanks for the help

rogzballz

iTrader: (9)

I would upgrade to performance wires

FrankT

The three plastic connectors going to the coil packs will be very brittle, expect for them to break; some leave them connected and push the coil packs out of the way.

No way would I consider anything but factory OEM wire set.

If there is oil present in the spark plug valley and it is not the result of oil spillage; then consider replacing the valve cover gaskets.

Good luck

SaiyanGS3

iTrader: (8)

1. Make sure you get the NGK or Denso plug that is double platinum. That's very important due to our cars having the wasted spark coil system. 400/30's don't have this so it's a little easier for them to source different plugs. 2. Change your wires AND your VC gaskets while you are there to avoid double labor. It doesn't make any sense to not change your wires and VC gaskets while you have everything torn apart. Wires, I would stick with OEM. Those wires got you to 148k...replace and they will get you to 300k.

I haven't changed my plugs yet myself and what I listed above is what I plan on doing at 150k or if I get the spark plug stumble before 150k, I'll change at that time. Our OEM plugs are top notch brands so that's why we are able to get the amount of miles out of them. IMO there is no other plug available that is better than NGK or Denso when it comes to a Japan made car.

AM21GS400

iTrader: (2)

I changed mine last night, I used NGK iridium plugs. The ones that were in there were Denso iridiums, and those were put in by the Lexus dealer quite some time ago.

I have an 00' GS400.

AZTurbo

iTrader: (10)

I would recommend NGK or Denso plugs only along with NGK or OEM Toyota Wires.

bizeau77

Thanks to everyone for the replies! Is much more involved in replacing the valve cover gasket? I've never had a car that required so much work just to replace the plugs. I'm fairly mechanically inclined, so I could probably figure it out without too much trouble. Definitely don't want to pay the shop $200 just to change the plugs! My car just recently started stumbling at idle, I'm hoping the new plugs and wires remedies this. Thanks again!

bizeau77

So I haven't made time to swap out the plugs yet but I have them here as well as the wires and valve cover gaskets. We're leaving in 2 days to go to Vegas and it's about a six hour drive so I was hoping to do it before I left. I called the dealer yesterday just to see how much labor would be to install my parts. Plugs and wires alone is 1.5 to 2 hours, but if I have them do the v.c. gaskets as well, it jumps up to 4.5 hours!? Does it really take 2.5 additional hours to replace those gaskets? With our trip so close I'm a little afraid to do it myself in case something happens while I'm in there and I get stuck or need to order additional parts (if I break something). Should I just worry about it when I get back? Do stock plugs with 148,000 mi. run a risk of anything bad happening on a 900 mile road trip aside from a little low-rpm stumble?

Thanks guys

mexikan

Wait until you come back <and yes it does take 2 more hours for valve covers, I had to do mine twice because it started leaking right after I replaced them... they're a pain to put on, I got them from FEL-PRO they're 4 pieces for each side... good luck

gittert

iTrader: (1)

4 piece for each side? wut? no

There's 1 gasket for each valve cover. When I did mine I replaced the plug boots for each coil as well as the wires. The wires that came OEM felt inferior to the new NGK's (even though my OEM wires lasted 250k miles!) so I bought the NGK's as well as NGK plugs. The VC gasket is just a good idea while you're there and have it all apart. The connectors are brittle so be careful, might not be a bad idea to buy a few connector housings just in case (typically the leads will be just fine, it's the housing that cracks apart, you can salvage the leads from the housing and just put them into the new housing).

mexikan

really when I did mine there was 4 pieces I had to put together. and it was from fel-pro.. normally there's 1 piece gasket but this one was 4,... first time I see this ...

gittert

iTrader: (1)

What did it look like and how did you "put it together". I also got mine from Fel-Pro

jase1942

Hey fellow clublexus'ers! First post here...and of course it begins with a question

I'm also looking to replace plugs, wires, and the valve cover gasket for my dad's 2004 GS 300. I was hoping for some advice on parts. Here's what I have so far:

1) Valve Cover Gasket FEL-PRO Part # VS50660R PermaDry molded rubber gskts. incl.
2) Spark Plugs NGK Part # 2978 Laser Platinum .044; OEM/OES Spark Plug
3) Spark Plug Wire NGK Part # 6404 3 Lead Slave Set

but not sure if I necessarily need...

4) COP Boot NGK Part# 58911 NGK Coin on Plug Boot


Would everyone recommend replacing the coil on plug boots as well? I ask because the NGK boots are ~$20/ea which would mean I'm out another $120 for what looks like little rubber gaskets. I'm still pricing stuff out between Rockauto, Amazon, and Advance Auto. (Rockauto wins on price, Amazon on shipping, and Advance has a $50 off $125 promo going on).

Also, if anyone has ordered the Fel Pro gaskets, how many gaskets come with an order? They show 3 in the picture, but I only need 2 right?

Thanks for the help, I really appreciate it!

SaiyanGS3

iTrader: (8)

I wanted to clear this up for people who look at this in the future. The NGK plug you listed will work, but it is NOT the OEM plug and will not last as long. We have the wasted spark system, which requires a double ground plug. I won't explain this to you, you can search here to see exactly what I'm talking about.

jase1942

Hey Goku, thanks for getting back to me. I just read the term "double platinum" spark plugs tossed around and thought it was interchangeable with "double ground" spark plugs. The NGK site lists these as double plats, but I guess they are not the multi-ground plugs that are recommended for the GS300.

Odd thing is, NGK and Rockauto lists the #2978 as the Original Equipment Manufacturer, and/or Original Equipment Service Part for an '04 GS300. From searching around I found people recommend either:

Denso (3289) PK16TR11
or
NGK BKR5EKPB-11 (4302)

However, neither of these come up on part searches, (Amazon, Rockauto, Advance, etc) when I put in my car details. Also, my manual states the Denso (3353) SK16R-P11 are recommended OE plugs to use, which is not a double ground plug. So... anyone with a part number for NGK or Denso Multi-Ground Electrode plugs that are compatible with an '04 GS300? Thanks.