Changed Spark Plugs Yesterday...Should I be Concerned?

[NJshadow93]

I changed my plugs yesterday and glad I did. The plugs I pulled, all Denso Iridiums, were in good shape for the exception of one or two of them. One of them was worse than the others by far.

All the plugs seems a little loose except for the two back ones. I torqued all the new ones to 15 ft/lb with anti seize.

What do you guys think? I replaced them with NGK Laser Iridiums. Also, this could just be in my head, but the truck feels a little slower after the change. By a little slower, I really mean SLIGHTLY. It idles perfectly, feels very smooth otherwise. My main concern is the one dirty plug though. Thanks!

 

[Gatafly]

That one in particular might have been just a fraction more loose than the others and been just enough to get a little blow by hence the reason it is dirty. Anytime you do something to your vehicle your mind always tries to make you feel something is different. . . . at least for me. If someone had changed the plugs and you did not know about it I bet you would never feel a difference. Hopefully you did check the gap before putting them in though. :wink:

I would not worry about that 1 plug. If you know the location it was in I would drive a couple thousand miles and pull the new plug from that location and check it.

 

[BOSMECH]

Yeah what Gatafly said.

 

[NJshadow93]

Thanks for the reply. I just visually checked the gaps, comparing them to the old ones. I do not have any special tools to gap the plugs. But like I said, it idles perfectly and there are no funny noises.

 

[Keros]

When putting in new plugs I use the 3/4 turn method NGK shows on their box. But when putting in used plugs (as in I took the plugs out for some purpose or another), I torque them to spec from the book.

Purpose being that the steel crush gasket is supposed to compress a certain amount when new, but once installed you'll need to rely on metal on metal squish for a seal.

I'm not sure if this is correct, but I've never had a loose spark plug since, nor have I ever had issues getting them out either.

As for the two plugs being different colours, I could only advise, as has been mentioned, to check them again in those cylinders in a few thousand miles. If they're different from another [good] position plug, then perhaps investigate the plug wires.

 

[chmura]

I wouldn't gap iridiums. You can scratch and damage the tip of the electrode. Not worth doing.

I been buying spark plugs from the dealers for all my cars and never gapped them. No issues. No mpg drop, etc. to each there own I suppose.

 

[Mtn.Runner]

I really like the OEM denso plugs. I've ran both ngk irids and lasers. I feel more power with OEMs.

 

[bvc]

I think you're ok. Recheck your torque after a week or two...mine were not even finger tight after a couple months.

Could also check for oil again at this point.

 

[lumpycat]

Looks like oil on the upper part of the plug. Could be the valve covers are leaking allowing oil into the plug area. The brown at the base of the insulator could be from the plug leaking internally. Can they do that? Otherwise they all look to be fireing OK.

 

[robhurlburt]

Looks like oil on the upper part of the plug. Could be the valve covers are leaking allowing oil into the plug area. The brown at the base of the insulator could be from the plug leaking internally. Can they do that? Otherwise they all look to be fireing OK.

i bet the oily one was from one of the cylinders by the firewall. IIRC the valve covers are known to leak a little there.

 

[NJshadow93]

The oily one was actually the second one on the passenger side. When you're standing in front of the truck, looking at the left of the engine, it is the second one from the front.

 

[MikeInNH]

The oil on the threads usually is an indicator of a leaky valve cover. If it's REALLY oily..then I'd worry about it.

As for gaping or not gaping new plugs...You should ALWAYS at least check the gap. You'll be wondering what the heck happened when you install plugs that are NOT gaped properly. And for those who's NEVER seen a plug that's not gaped properly...they haven't don't enough tuneups. I've seen them from the dealer or local or even national parts store where the gap was significantly out of spec. While it's rare these days...it still happens. Since Toyota doesn't make plugs...they are subject to the same problems the local parts store does that sells Denso or NGK plugs. Why would it be different. As for hurting an Iridium plug....well if you know what you're doing there isn't a problem. I sure wouldn't take the chance of NOT checking a plugs gap...The frustration of an engine NOT running right far out weighs the cost of a plug.