Platinum Plugs - How long until next change?

[MadDog]

Hey guys, just curious what you guys are thinking. I changed over from the stock NGK plugs to the Bosch Double-Tip platinums today and I'm wondering what the interval should be until the next plug change - if ever. Only had 22K on the truck anyway so it's not like it really needed it and the NGK's weren't too worn out, but I figured the extra power & MPG benefits outweighed the cost and I was in a tinkering mood . Through the little I've read, some people say you never have to change out platinum plugs again, but I'm a bit more conservative on my maintenance planning. What is your opinion on this, when/would you change the plugs out in the vehicle's life? As always, thanks!

 

[tjkj2002]

About the same interval as recommended,every 30,000miles.Even running platinum's you'll notice a big difference after changing them in 30,000miles.Plus plugs are cheap and easy to replace in the KJ so why not change them often to keep the best performance and mpg's.It's best to do a induction system cleaning before changing the plugs,really helps also.

 

[MadDog]

Hey TJ, can you elaborate on the induction system cleaning? What's involved in that? I've not heard that particular term thrown out there before...

 

[valvestem]

Hey TJ, can you elaborate on the induction system cleaning? What's involved in that? I've not heard that particular term thrown out there before...

Change the air filter, is my guess. If he means air induction.

 

[kb0nly]

I think he's referring to the intake system cleaning mentioned in the service manual, it uses a spray in type cleaner to clean the throttle body and intake manifold, it fouls the plugs pretty good so you want to do that and then replace the plugs, if your going to do the cleaning process that is.

I have seen dealers do this when something comes in with an intermittent ignition problem or it has misfires. Usually you know when they are doing one cause the guys will back it out of the shop and then you see this huge cloud of exhaust from that crap burning off. Then they pull it back in and swap the plugs.

 

[MadDog]

Thanks for the explanation guys. No ignition issues or anything right now since the engine is still pretty young, so methink another 30K and I will do the induction system cleaning and then change the plugs. Thanks a lot guys!

 

[Powerslave]

I also used the Bosch Platinum +2 in my 3.7, and I will be leaving them in for the duration of the vehicles life, unless I fall upon a set of Diamond Fire plugs cheap or free. Platinum will last up to three times longer than Copper tip plugs. My avenger came with NGK Platinum plugs, and; I changed them at <= 70K (60K is the change interval), and used +4s, and never changed them since. I traded it in for this jeep, at over 150K miles with those in it, ran smooth as ever. Japanese engineering helps with all the counter weights on the crank of the 6G73, you could hardy ever tell the car was running. Very reliable engine, was smooth always, just like the 2.0 (1990cc) I4 I had in my 1969 BMW 2002. I mentioned elsewhere it was a 79, was a type-o, they were a 1968 to 1976. All lettering and gauges were in German too, was cool...

You can use SeaFoam to clean the induction system. Follow the directions. My tube blew off the nozzle, and went into the intake. Where it is? Who knows. I have put 6k miles on it since, and I don't know where the plastic tube is, or what happened to it. With my avenger, I removed the intake plenum and soaked it in kerosene, then Sea Foamed it clean. I did that at the same time I changed the plugs, as I was going to change the valve cover gaskets, only the plug valley seals were leaking, but I could not get the covers off. So, I wrapped each plug TOP, where it seals into the valley, in three layers of electrical tape, put them back in, no more leaks.

ANYHOW; You will get many opinions, this is what I do, HAVE been doing since 1987, my cars last and run just fine, till they rust out completely out, so whatever. The only two reasons I got rid of the Avenger? I was tired of having a sled in the winter, and the bottom of rear wheel wells were rusting out, and a jack almost went through the body of the driver side, at the rear jack point. Did not want to invest in the body, and weighed the options with a 4x4 in winter, and that won out.

Platinum plugs rare cool...

 

[tjkj2002]

Thanks for the explanation guys. No ignition issues or anything right now since the engine is still pretty young, so methink another 30K and I will do the induction system cleaning and then change the plugs. Thanks a lot guys!

OEM plugs are crappy NGK copper core plugs,might want to change them before 60K(30K is the change interval).Just because you think you don't have any problems does not mean there is not carbon build up on your valves and combustion chambers.It has been proven you can get up to 10% better mpg's doing a fuel induction cleaning at least once a year and changing the plugs at the manufacture specified interval no matter what plug you use.

Every engine is different and some engines like certian plugs better then others.Just like Champion plugs for instance,I wouldn't run those plugs in a lawn mower I was trying to blow up but dang there about the best plugs for the 4.0 I-6(RIP),or how Ford engines do not run good on Bosch plugs,or GM engines hate almost every plug made.Those +2/+4/E3 plugs are a gimik,you will see the same gains as those plugs claim from just about any plug since when you change the plugs the new ones(no matter what type) will always out perform the older worn plugs(that is fact) and those gimik +2/+4/E3 plugs are banking on your stupidity.Platnuim plugs can last longer then copper core plugs when the engine is designed to run them,our 3.7's are not designed to run platnium plugs so they do not any longer then copper core plugs.And yes engines are designed to run certian stuff like plugs,oil weights,and octane.As far as anyone saying that there 100,000miles platniums made the engine run smoothly is flat out lying,partly from not knowing any better since the change is rather gratual and you will not really notice the change since it occures over a long period of time so you really do not notice,just like worn shocks/struts.They may feel fine to you but to some one else they feel like crap.I've been working in the automotive field for over 25 years,built more engines then I can remember(trans also) and those gimik plugs just don't work.The only plug that will last over 100,000miles is Iriduim plugs but most do not need that type of plug.

When I built my BBO engine for my Cutlass I tried Bosch platniums for the 1st fire up,fouled them out in less then 5mins,same went for Autolite platnuims.Had to break the engine in with good old Autolite copper core plugs(though went through a few sets due to melting).The magic cure was Denso Iriduim plugs that could withstand the 13:1 compression ratio.The oposite was true about the SBC I built for my Blazer,ran like crap with platnium and iriduim plugs but ran like a champ(25HP/30lbs-ft of torque increase over platnuim/iriduim plugs)) using copper core Autolite plugs.


But as always it's your vehicle and you can do as you wish,most of what I state here is mostly from experiance in a long carrier working on vehicles(ASE Master Certified Tech since 1999).What works for one person and vehicle may not(most always) work for another even with the same vehicle.

 

[MadDog]

Hope you didn't misread what I wrote TJ - I already changed the stock NGK's to the Bosch +2's, so I am thinking it won't need the induction system cleaning now, but I will change to another set of platinums after another 30K and then do the induction system cleaning then. I tend to be more conservative on the maintenance side of things. I usually change things before they are due, which is why the idea of lifetime platinum plugs just doesn't sit right with me - I would rather change 'em just to be safe. As for single vs. +2 vs. +4, yeah I realized that there were minimal gains in performance to be had, I mostly wanted the +2's because they are gapped from the factory and I didn't want to have to deal with checking the gap on the single tips.