VW's 40K Plug Interval: The Result of Doubling It

[Jarlaxle]

Originally Posted By: bepperb
I thought everyone specd plugs for 100,000 miles or more? There's no reason that same double platinum plug wouldn't be in the engine for 100~120,000 miles if it was an American or Japanese car.

They look decent to me. I'd be surprised if there is a big mileage difference, but at the same time you'd need to compare the gap to the new to say.


My Hemi Magnum called for plugs (and it used 16) every 36K!

Just one reason I no longer own that car.

Having said that, those look better than the Delcos that came out of my uncle's F-250!

My first LT1 Caprice had its original[/i] plugs and wires with 130,000 miles! Needless to say, there wasn't much left of them...though the car ran perfectly right up until I drove through a huge puddle. Then they got soaked, and it ran...well, let's say it ran.

 

[hattaresguy]

40k miles? Really? Well its VW so that's not a surprise.

I'd just change them at 100k or more like every other car on the market. I doubt most owners every change them.

 

[Colt45ws]

Originally Posted By: scurvy

Before removal, the base of the threads always sees a shot of P'Blaster and I only use a 1/4" drive ratchet & socket. Spark plugs or glow plugs always go back in with a tiny dab of nickel-based anti-seize on the threads and a similar tiny dab of dielectric grease on the insulator where the boot goes. Otherwise next time they can and do squeak and groan and gall threads. Do I know better than the propellerheads in Wolfsburg? Depends on who you ask. I know what works for me...

Except for bottom of the barrel copper plugs, most plugs have a nickel plating on the threads. So effectively they have their own anti-sieze.

 

[The Critic]

Originally Posted By: mechtech2

Good thing she didn't listen to your advice a while back.


Was I supposed to blatantly ignore the mfg's service interval and not advise accordingly?

I find it ironic that we are critical of the lax fluid change intervals suggested by OEMs, but we turn around and seem perfectly okay about running plugs for 2-3x the recommended interval per the mfg.

 

[scurvy]

Originally Posted By: Colt45ws
Except for bottom of the barrel copper plugs, most plugs have a nickel plating on the threads. So effectively they have their own anti-sieze.


Could be - but how do you know for sure? How do you know if there's enough of it to last the entire time your plugs are in there? If I had a dollar for every squeaky, binding glowplug I've had to nervously sweat over slowly getting out, I could buy a lifetime of anti-seize.

A few pennies worth of nickel anti-seize is worth belt & braces protection in my opinion.

 

[threeputtpar]

I believe that there are two reasons that VAG recommends 40k mile plug intervals. My A6 2.7t has the same recomendation.

Yes, on the 2.slow and 2.5 engines you could run them longer than 40k, but the recomendation is really for the 1.8t and 2.0t engines. I've seen plugs from a 1.8t 40k, and those plugs were in need of changing because of the forced induction I believe.

The other reason is they don't want the aluminum head's threads to be damaged when someone leaves plugs in there for 100k miles. For that reason, I at least check them on my A6 at 40k and if I feel it's necessary I change them. The last 40k mile interval, they were all past the acceptable gap, so new ones went in.

Same thing for the 4.0 in my Mountaineer. Those were changed at 50k because the plugs in the two cylinders closest to the firewall were in rough shape. Ford calls for a 100k mile interval.

 

[mechtech2]

"Same thing for the 4.0 in my Mountaineer. Those were changed at 50k because the plugs in the two cylinders closest to the firewall were in rough shape. Ford calls for a 100k mile interval."

Should Critic blatantly ignore the factory intervals here also?
answer: Again, yes.

Moral:
Check plugs for type and condition.

 

[The Critic]

Originally Posted By: mechtech2

Moral:
Check plugs for type and condition.


The plugs cannot be reused once removed. The washers are one-time use and may not reseal properly.

 

[antiqueshell]

Originally Posted By: The Critic


The plugs cannot be reused once removed. The washers are one-time use and may not reseal properly.


For most modern vehicle applications this is correct.

WARNING! If you remove a spark plug with a nickel plating on the threads and then reinstall that plug those threads might seize the next time you try and remove it!!!!! Something to think about. Don't be penny wise and pound foolish!

 

[The Critic]

Originally Posted By: threeputtpar
I believe that there are two reasons that VAG recommends 40k mile plug intervals. My A6 2.7t has the same recomendation.

Yes, on the 2.slow and 2.5 engines you could run them longer than 40k, but the recomendation is really for the 1.8t and 2.0t engines. I've seen plugs from a 1.8t 40k, and those plugs were in need of changing because of the forced induction I believe.


Note: The 2.0T requires spark plug changes every 60k instead of 40k. Judging from the info online, 40k may be more realistic, but YMMV.

 

[229]

Antiseeze decreases the conductivity and manufacturer's discourage use. I had to change a set of plugs because Antiseeze was causing misfires. Use good plugs, preferably factory spec that have a nickel coating already applied.

 

[The Critic]

Originally Posted By: 229
Antiseeze decreases the conductivity and manufacturer's discourage use. I had to change a set of plugs because Antiseeze was causing misfires. Use good plugs, preferably factory spec that have a nickel coating already applied.


OT, Honda states to use anti-seize in the FSM on the Honda 2.4 engine that I was referencing. They also say to torque to 13 ft-lbs, which is less than the 18 that most others recommend, fwiw.

 

[229]

Good to know. Use sparingly.

 

[rcy]

Originally Posted By: The Critic
Originally Posted By: 229
Antiseeze decreases the conductivity and manufacturer's discourage use. I had to change a set of plugs because Antiseeze was causing misfires. Use good plugs, preferably factory spec that have a nickel coating already applied.


OT, Honda states to use anti-seize in the FSM on the Honda 2.4 engine that I was referencing. They also say to torque to 13 ft-lbs, which is less than the 18 that most others recommend, fwiw.


The FSM for my 2006 Acura MDX also states to use anti-seize on the plugs.

 

[PandaBear]

Originally Posted By: antiqueshell
Originally Posted By: The Critic


The plugs cannot be reused once removed. The washers are one-time use and may not reseal properly.


For most modern vehicle applications this is correct.

WARNING! If you remove a spark plug with a nickel plating on the threads and then reinstall that plug those threads might seize the next time you try and remove it!!!!! Something to think about. Don't be penny wise and pound foolish!



Seal may not be perfect, but it should still "seal" significant enough that you will not notice any problem. Like reusing drain plug crush washer once or twice would not cause problem. Now if you reinstall the plug 15 times then that's a different story.

Even the Ford OEM plugs that do not have nickle coating and rust would not seize at just 30k. If you take it off at 30-60k and inspect, and install it back for another 30-60k, it should be fine. If you take it off at 120k and reinstall it back for another 120k, that's another story.

But we human has to deal with our own comfort level. Just because you can wear your underwear for 1 week doesn't means it is something people will feel comfortable to.

 

[The Critic]

I measured the gap on the plugs tonight.

The gap on the new NGK PZFR5J11 plugs is supposed to be 0.043".

The gap on all of the old plugs was 0.049". So, the plugs were not significantly worn.

 

[UG_Passat]

part number ending in 11 = 1.1mm gap

 

[GSCJR]

I have used NGK plugs exclusively in ALL my engines for years. Regardless of make or model without any issues.

Same as above with the use of Anti-seize on ALL threads.

 

[tarbasd]

Originally Posted By: PandaBear

Seal may not be perfect, but it should still "seal" significant enough that you will not notice any problem. Like reusing drain plug crush washer once or twice would not cause problem. Now if you reinstall the plug 15 times then that's a different story.


LOL, I reused my drain plug washer on the Corolla about 10 times with no problem. I usually forget to get a new washer.

I would reuse a spark plug in a pinch, but I prefer not to.

 

[Ryan02SS]

Originally Posted By: threeputtpar
I believe that there are two reasons that VAG recommends 40k mile plug intervals. My A6 2.7t has the same recomendation.

Yes, on the 2.slow and 2.5 engines you could run them longer than 40k, but the recomendation is really for the 1.8t and 2.0t engines. I've seen plugs from a 1.8t 40k, and those plugs were in need of changing because of the forced induction I believe.

The other reason is they don't want the aluminum head's threads to be damaged when someone leaves plugs in there for 100k miles. For that reason, I at least check them on my A6 at 40k and if I feel it's necessary I change them. The last 40k mile interval, they were all past the acceptable gap, so new ones went in.

Same thing for the 4.0 in my Mountaineer. Those were changed at 50k because the plugs in the two cylinders closest to the firewall were in rough shape. Ford calls for a 100k mile interval.


I agree. On our 1.8T it is every 40K or sooner. Same goes for the air filter. The 1.8T is very hard on plugs.