AL13NV8D3R

I own a 2014 GS 350 RWD with Luxury package @ 85,000 miles on the odo. My service manager wants to sell me spark plugs service for my vehicle for $680 labor included. He said my spark plug should have been replaced at 60,000 mark. I checked my owners service manual and do not see anywhere at 60k or 85k or 90k miles indicating i need new spark plugs.

Can anyone tell me if the price dealer asking is reasonable and if i even need spark plugs replaced because of current milage milage. Thanks

er34

60k would be early. I certainly wouldn't pay $680 for it. You can get 6 plugs for about 80, so you are practically paying $600 in labor for something that a DIYer could do relatively easily.

bclexus

Your spark plugs will perform perfectly far into 6-digit mileage territory with no loss of performance or decreased mpg. There is really no need to have the spark plugs replaced except for one thing - that is to retain the warranty on the emission system, which I believe runs out at 100k miles anyway.

peasodos

iTrader: (1)

$680 is a massive rip off for a job that takes less than 30 minutes. I think the factory recommendation is 100k or so. The dealer is trying to take advantage of you. I would file a complaint with Lexus corporate, avoid them all together, and get the work done at your local toyota dealer at the recommended interval or local shop.

Spark plugs are easy to change.

RXGS

iTrader: (2)

60k is the interval for this engine, so they are due, but as others have said, $680 is very high. Go to YouTube and you’ll see how easy a job it is, and if nothing else, you’ll get a better idea of how much a service like this would cost elsewhere.

SpicedRum

My 2018 owners manual states a 60K replacement interval, so I think it's wise to go ahead and do the plugs sooner than later. Usually the Iridium plugs are spec'd to go longer, so there must be a good reason why Lexus is suggesting an earlier change window. Probably concerns over increased spark plug gaps over time, but I can't be sure.

As for the cost, geez....that's ridiculous to ask so much for the plug change. While I haven't done them in this car yet, I'm still under 1K at the moment, I've done plenty of them in many cars/trucks/boats/cycles and it's usually not a difficult job at all, especially in a V designed engine as the plugs are easy to get to.

The right tools make all the difference. I seem to recall a DIY somewhere on this site. Since all modern Lexus V6's use this same engine, tips from the other forum areas could probably be applied.

My advice would be to read up on how to, then do it yourself, but if you're totally scared to do it...buy the plugs and take the car to a small independent shop, or get a quote from a Toyota dealer. Note that it's best to change plugs on a COLD engine, so ask if you can leave your car overnight and have the change done in the morning when the engine is cold.

Patrick4GS

iTrader: (2)

I changed mine a few weeks ago on my 2013. $200 for OEM Lexus parts from the dealer (Canadian dollars) and about 45 minutes to change. No special tools needed and pretty straight forward.

My car has 140,000 kms on it and the old plugs looked fine on removal. No noticeable difference with the new plugs installed, not that I expected any.

$680 is crazy expensive, was something being done other than the spark plug change?

AL13NV8D3R

Thanks guys. i guess I will get a quote from my local Toyota shop. I am very knowlegable with electronics and tech but car engines are beyond my ability. When I get a quote from Toyota I will let you guys know.

Also while they are replacing spark plugs are there any other services need done too like water pump, starter?

bclexus

You could have gone twice that mileage (280k km or 174k miles) and the original plugs would have [still] looked fine, and there would [still] be no noticeable difference.

SpicedRum

That's great news. Viewing the condition of spark plugs tells a lot about your engine's health. A white-ish ash like color usually indicated a lean running engine, which would be the case for most modern, well designed, fuel injected engines in good health. A medium gray indicates a good balance between lean and rich whereas black indicates rich--meaning too much fuel is being unburned (perhaps a stuck injector, bad tune) or perhaps the plug is not sparking each time, creating excessive unburnt fuel in the cylinder that leads to carbon buildup.

A very dirty running, high performance engine such as my old Yamaha WR400 4 stroke dirt bike (12:1 compression, 5 valves, accelerator pump on carburetor) will almost always have black plug...so much that it could--and indeed does often, prevent the engine from starting. If you cranked the throttle before starting, the accel pump would shoot in raw gas and flood it. Once you got it running (and this was usually not fun after it flooded), it would foul the plug further. Eventually there would be enough carbon that it would not start at all, no matter what. You had to replace it.

I am guessing that Lexus is concerned about the increasing gap between the two electrodes which is a normal to occur by simply using it. When the gap becomes too great, the voltage required to ignite the spark increases. If the gap and required voltage is too much for the ignition system to generate, it will miss-fire and reduce power, not to mention leave behind the unburned fuel that contributes to carbon fouling during the next spark cycle. And generating higher voltages can be a little harder on the coils, decreasing their life span (although modern coils may be handle this better than older types, I'm not certain here?).

Another issue is cracking of the ceramic insulator. Eventually this will happen, especially when there are excessive hot/cold cycles. When the insulation cracks, voltage escapes and never gets to the electrodes, reducing or eliminate the spark. This will lead to poor performance and fuel economy. I would think that the check engine light with a miss-fire diagnosis would occur here.

Anyway, by measuring the gap and inspecting the plug closely for cracks, and the electrode colors, the dealer tech can get a good understanding of what might be wrong with fueling or ignition. For example, if 5 of the 6 plugs are gray-white and one is black, the cylinder with the black plug probably has a bad injector, bad plug, compression leak or a software issue in the ignition (among other computer related issues).

So this is somewhat of a preventative check too. This is why it's important to keep track of the plugs coming out of each cylinder, so you know the bad plug was in a certain cylinder and can further diagnose issues.

When the time comes I'll replace them myself...this job looks pretty easy to me. Perhaps two hours max working very slowly--probably 45 mins realistically. But, if you're like me, I'll leave a tool somewhere and spend more time looking for the wrench then it takes to use the darn thing. And it's always found right under my nose! lol

bclexus

The gap on iridium spark plugs are not going to wear enough to even be measurable with typical gap tools.

Here is a spark plug pulled at 60k miles that displays no wearing of the central and side electrode gap points. It's as good as brand new...

peasodos

iTrader: (1)

Granted I do have the 450h, but I can't imagine the 350 service requirement being that much different.

The only service interval for the Spark Plugs is 12 years or 120,000 miles.
Then at the bottom of the page it says "Required under the terms of the Emission Control Warranty

SpicedRum

It does actually say 60K miles for spark plug replacement in my 2018 GS350 owners manual and also footnotes that this is required under the terms of the Emissions control warranty.

There must be a good reason to replace them and I agree it's odd that the hybrid and non-hybrid change intervals are so different. Are you sure it's not listed in the 60K section? If not, maybe they made a mistake in one of the manual versions (hybrid vs. non)? Weird....

peasodos

iTrader: (1)

Yes. I check the manual in my car and the online manual from Lexus for my car, both are the same.
I've owned a Honda were the service requirement was 100k and it also used the same Denso brand spark plugs Lexus/Toyota uses in our cars.

The electric motor is constantly assisting the gas motor and just like the picture someone posted at the 60k mileage the spark plugs look in great condition.

GregCanada

DId mine at 60k. $120 for new plugs and 1hour of labour. Dealer wanted $500. Went to Vegas instead