Spark plugs and wire change - old plug pics

[joutlaw]

I changed the plugs and wires on my 2004 Chevrolet Silverado 5.3L V8.

Overall it wasn't too bad. The boots were a pain on the drivers side.

My pictures have the old spark plugs labeled as P1, P2, P3, and P4 for the passenger side and D1, D2, 3D (pen messed up), and D4. D1 and P1 are closest to the front of the engine where D4 and P4 are closest to the firewall.

I was unsure of the history of the plugs and wires. The plugs I removed were NGK PZTR5A/15 with AC Delco 12567759 also labeled on the plugs. They were gapped at .060 and didn't appear to have much wear. The wires removed were AC Delco 0744's.

The is P2. It has the darkest coloring in the threads out of all eight plugs

Drivers side

Passenger side

I replaced them AC Delco 41-110 which come gapped at .040 and Bosch 09017 plug wires which were a little longer than stock. GM has released a TSB noting to change the gap from .060 to .040 on the LS series of engines. The 41-110's are iridium and were pregapped at .040.

Why is the the P2 plug so much darker? The old plugs appear to have normal wear with the right colorings. I have around 140K on the truck now. I don't know if NGK plugs come stock or if someone replaced them before.

 

[SuperSix]

Looks like it's running a BIT rich, but nothing to worry about. Where do you live/what do you do to get the plugs that dirty?

They have probably been replaced - platinum are recommended to be replaced at 100k, most replace them before that.

Are the 41-110 what the manufacturer recommends? If no, are they the same heat range?

Also - don't forget the dielectric grease on the boots - keeps them from sticking to the plug ceramic.

 

[joutlaw]

Looks like it's running a BIT rich, but nothing to worry about. Where do you live/what do you do to get the plugs that dirty?

They have probably been replaced - platinum are recommended to be replaced at 100k, most replace them before that.

Are the 41-110 what the manufacturer recommends? If no, are they the same heat range?

Also - don't forget the dielectric grease on the boots - keeps them from sticking to the plug ceramic.

I've had my PCM tuned so I'm not sure if thats why I'm running rich. The electrodes look pretty normal from what I've read. I live in MS and this truck goes off-road a good bit. I wasn't expecting it to be so dirty.

The 41-110's are recommended by GM for LS engines.

Yep I used some dielectric grease just in case I ever do this job again. I ended up keeping the old plugs in my truck's toolbox in case something ever goes wrong down the road.

 

[5150MyU]

P2 is dark because that cylinder has...........just drive the thing.

 

[AMCRambler]

P2 is dark because that cylinder has...........just drive the thing.

Lol. He does have a point though. Those plugs look pretty good for the number of miles they've probably got on them. I don't think you have to worry that one is slightly darker. As SuperSix stated that cylinder might be running a bit rich. Maybe that injector is wearing out or it was replaced with the wrong size injector and is shooting more fuel. If the truck is running fine, I don't think you have to worry about it.

 

[5150MyU]

Also I wouldn't be concerned with the threads as much as the tips P3+P4 look rough.
Those look dark.You need a full engine analisys and rings, and valves and,,and ,,and.

 

[SuperSix]

Also I wouldn't be concerned with the threads as much as the tips P3+P4 look rough.
Those look dark.You need a full engine analisys and rings, and valves and,,and ,,and.

They look fine, they are platinum plugs, they are supposed to look like that.

 

[5150MyU]

^^^I was talking about the black on the plug itself and not the electrode AND I was just kidding.

 

[Pacfanweb]

Plugs look fine. They all pretty much look like that. Unless you have one cylinder totally flooding or not getting any gas at all, you can't tell much by reading plugs with today's engines.

I removed plugs from my 99 Tahoe last weekend that were original with over 150k miles on them.....they really didn't look much worse than yours. And were still firing just fine.

Biggest gap was MAYBE .070", which a modern ignition can easily jump.

In fact, up to a certain point, a good ignition will produce a bigger/hotter/better spark as the gap increases.....it HAS to to be able to jump the gap.

I don't think it makes as much difference with OBDII cars as on older ones, but back in the early 90's, I remember the Explorers coming with platinum plugs that didn't get replaced until 60k miles. They had very powerful DIS (distributorless ignition systems). As the gap on the plugs increased, the spark got a LOT hotter, and fuel efficiency went up as a result.

We had a lot of people come back after their 60k tuneups complaining of decreased fuel mileage, with no apparent problem with the way the engines ran. After awhile, we and Ford figured out that the decrease came from the decreased spark caused by smaller plug gaps.
Some of the plugs I removed had over an .080" gap and were still firing fine. I believe the gaps started at .052-.054".

 

[sjwaste]

Those look fine. Color is going to vary - on some engines, certain cylinders run hotter than others. On mine, #5/6 (its a straight 6) are the hottest and those plugs always come out a lighter tan than the rest. As long as you're not seeing melted bits all over the electrodes and they're not white, you're in good shape. They're rarely going to come out identical, and yours look close enough to not worry.

 

[alkalinetaupehat]

An option if you're concerned about where the engine is at mechanically is oil analysis. Blackstone Laboratories does analysis for $25 a sample, I've enjoyed their services with samples from my car and my sister's new car. They noted higher upper-bearing wear on her car and a beginning coolant leak on mine, it's been worth every dollar for me.

 

[5150MyU]

^^Upper bearing wear?So is that the topside of the camshaft bearings.I would have to say normal wear and tear.
Coolant leak-=PPM(parts per million)is it significant -=I'll bet I can do an engine analisys on any engine and find something amiss in there.

 

[Pacfanweb]

^^Upper bearing wear?So is that the topside of the camshaft bearings.I would have to say normal wear and tear.
Coolant leak-=PPM(parts per million)is it significant -=I'll bet I can do an engine analisys on any engine and find something amiss in there.

Yep. Analysis is pretty much useless on regular cars, and truly useless if you don't do it every oil change so you get a total picture and can see if anything is changing or it's just normal.

Lots of engines use a little coolant, and all engines wear. Nothing new there.

Change your oil when you're supposed to and forget the analysis, unless you just like geeky things and don't mind paying for them.

 

[5150MyU]

Yeah, what I meant-getting sarcasictic with some of these people-sorry.