How long can you get out of a set of spark plugs.

[Johnp33]

I really recommend the very best plug you can afford, places like Rock Auto, you can get them cheap.
You want to be sure you use Never-size, as they will size in some engines and then you have a bigger problem.
Extending the mileage on a set of plugs with the price of fuel does not make any sense.
I do all my own repairs and will remove the plugs at about 1/2 their life to inspect and re-gap them and re-coat with never size.
If you have a Ford 3 valve 5.4 it is especially important.

 

[Alan L.]

2001 GmC Yukon XL - changed the plugs at 160K and they looked fine.

 

[duroc]

If you have a Ford 3 valve 5.4 it is especially important.

I don't necessarily agree with waiting until you accumulate 100K miles before pulling spark plugs. The above mentioned Ford is a good example. A friend of mine bought a 2005 F-150 that only had 29K, but was 5 years old. I advised him to have the plugs checked because they are known for seizing and/or breaking when removing. Upon doing-so, the dealer broke 3 of the plugs and the remaining plugs were not all that easy to remove, plus, they weren't all that great looking. Ford has a tool for removing broken plugs, but the cost of removal is not always cheap. IMO, it doesn't hurt to pull the plugs sooner and at least check them for wear. YMMV!

 

[super55]

See this is interesting about broken plugs. I've changed a fair amount of plugs over the years and only had one break and that was on a GEO years ago with an aluminum head. I've never had an issue with cast iron heads. Any particular brand more prone to break than others? I've owned GM products the majority of my life and never had an AC Delco break on me the only one that did break was a champion.

 

[duroc]

See this is interesting about broken plugs. I've changed a fair amount of plugs over the years and only had one break and that was on a GEO years ago with an aluminum head. I've never had an issue with cast iron heads. Any particular brand more prone to break than others? I've owned GM products the majority of my life and never had an AC Delco break on me the only one that did break was a champion.

Can't say that one is more prone to breakage over the next, but when I wrenched at a Chev dealer we had several vehicles with plugs that were a total bear to remove. One of the most common one was the pickup truck. The plugs that gave the most problems were #6 or #8 because the exhaust heat riser was located near them. When GM changed to the gasketless plugs is when the problems began. I haven't heard of any of those problems to date, other than the Ford.

Sorry for the hi-jack.

 

[Johnp33]

By far Ford has the most problems with plugs seizing and breaking, you have to let the unit cool before you ever start and blow out the area, then when the plug first starts turning blow out the area again. An aluminum head with the engine even warm can seize onto the plug.
90% of the people I know that moonlight will not touch a Ford 5.4 3 valve as most times if the plug breaks you have to remove the head to remove the broken piece and repair the threads. Many will turn out a few threads then seize.
I actually know a guy that specialises in those engines, and removing the heads.

 

[jonyyuma]

Driving until you have started noticing a miss or stumble seems to be asking for extra trouble...After 100k, then the risk of having a siezed plug seems to be normal.. Myself, they come out sometime close to recommended mileage. Plugs all need to fire perfectly to stretch out your mileage..Ie I like the iridium plugs they seem to wear less and fire longer..

 

[rsewill]

Seems with electronic ignition you need to change the plug wires more than the plugs. I'm just glad mine are all Diesels.

 

[Diamondpilot]

By far Ford has the most problems with plugs seizing and breaking, you have to let the unit cool before you ever start and blow out the area, then when the plug first starts turning blow out the area again. An aluminum head with the engine even warm can seize onto the plug.
90% of the people I know that moonlight will not touch a Ford 5.4 3 valve as most times if the plug breaks you have to remove the head to remove the broken piece and repair the threads. Many will turn out a few threads then seize.
I actually know a guy that specialises in those engines, and removing the heads.

You do not have to remove the heads. My BIL had one break and $40 at the local Ford Dealer had it out. They have a special tool to fix it.

I also had a customer of mine with a 2003 V10 F-350 blow 3 plugs out. They fixed it for about $400 in the truck.

Chris

 

[Diamondpilot]

Seems with electronic ignition you need to change the plug wires more than the plugs. I'm just glad mine are all Diesels.

Plug wires? I have not owned a vehicle in 10 years with plug wires. Now all them are Coil On Plug design.

Chris