Nissan Frontier VQ40 plugs changed at 100K miles

[SC Maintenance]

Changed plugs tonight. My VQ40 just rolled past 170K. I changed them the first time early around 70K. Factory spec is 105K miles. These are factory spec NGK Iridium plugs. Same thing went back in - purchased from RA.

One of the boots came out broken. I have had this issue before. There is one plug directly under the intake manifold, Nissan says to remove the manifold, but I have now done this 5 times on VQ40's without removing the manifold - but it seems this is the risk you run. Strangely this one never had a misfire. I checked the misfire logs in torque pro recently - none - so its not that its not misfiring infrequently - there were literally zero logged on that cylinder. Another cylinder actually had a couple - which still isn't a big deal. Guess I got lucky. Replaced the boot - I have a couple spares.

 

[slacktide_bitog]

They look good

 

[JavierH19]

Electrode looks surprisingly good.

 

[2002 Maxima SE]

I own a 23 Frontier that Nissan also recommends removing the intake manifold to access the front spark plug. What's your process to remove and reinstall without removing the manifold?

 

[SC Maintenance]

I own a 23 Frontier that Nissan also recommends removing the intake manifold to access the front spark plug. What's your process to remove and reinstall without removing the manifold?

I have no idea if the VQ38DD in the new truck is anywhere near the same as my VQ40DE. However on mine there is space. Hard part is getting the coil out - you have to push the coil forward - or back - and bend the boot a bit. Once its out the plug itself is pretty easy as there is a gap in the intake big enough for a socket, but not big enough to get the coil through. I use a flex spark plug socket then a second flex joint then a wobble - or something like that. Getting the plug back in is the reverse, and it can be a bit of a fight. Patience is key - I need to continually remind myself.

I have taken the intake off on my other one - to do the valve cover gaskets, and while its not that hard, it takes a lot more time. 6 plugs I think I did in about 90 minutes - with at least half that time for the one under the intake. Manifold off and on I would guess might be 4 hours total? I actually am more worried doing it that way. There are a lot of connectors to break. My way worst case is I break a $40 coil, or in todays episode a $12 boot.

 

[MolaKule]

Changed plugs tonight. My VQ40 just rolled past 170K. I changed them the first time early around 70K. Factory spec is 105K miles. These are factory spec NGK Iridium plugs. Same thing went back in - purchased from RA.

One of the boots came out broken. I have had this issue before. There is one plug directly under the intake manifold, Nissan says to remove the manifold, but I have now done this 5 times on VQ40's without removing the manifold - but it seems this is the risk you run. Strangely this one never had a misfire. I checked the misfire logs in torque pro recently - none - so its not that its not misfiring infrequently - there were literally zero logged on that cylinder. Another cylinder actually had a couple - which still isn't a big deal. Guess I got lucky. Replaced the boot - I have a couple spares.

View attachment 196534View attachment 196535View attachment 196536

I have a 2012 4X4 and change plugs every 75k miles or so and they look very similar to yours each time. Never had a misfire code.

 

[Soft Cars]

They're dry, but why the brown soot staining the otherwise nice white ceramic insulators?

 

[Sierra048]

My wife and I had a Nissan Xterra and a Frontier with the same engine. Rock solid engines. And I changed the plugs on each one of them. I removed the intake manifold when I did them. With the limited space for that one spark plug I just didn't see the need to fight with it. It was also a great time to replace the PCV valve that's at the rear of the engine on the same side.

 

[SC Maintenance]

They're dry, but why the brown soot staining the otherwise nice white ceramic insulators?

I think thats what there supposed to look like? 100K miles of heat? Maybe someone knows.

 

[SC Maintenance]

My wife and I had a Nissan Xterra and a Frontier with the same engine. Rock solid engines. And I changed the plugs on each one of them. I removed the intake manifold when I did them. With the limited space for that one spark plug I just didn't see the need to fight with it. It was also a great time to replace the PCV valve that's at the rear of the engine on the same side.

I have an Xterra as well - just gave it to my daughter. It has 395K miles. Only significant issues you wouldn't expect was the timing chain guides (OEM defect in a few years) and the heater core. Best vehicle I have ever owned - not even close.

 

[FowVay]

I recently changed the plugs on my 2017 4-cylinder. I had 105,300 miles at time of removal and the plugs looked just like yours. I think they could have easily gone another 50,000 miles. I had no misfires, rough running... nothing. My engine uses a different plug - NGK PLZKAR6A-11. They're pricey little suckers but if they last ten years then I can't complain.

It's amazing how reliable these ignition systems are on modern vehicles.

 

[SC Maintenance]

So go figure - went on a 100 mile drive and I knew I felt something - very slight misfire on cylinder 5. Not enough to register any codes or pending codes, but the registers don't lie. I guess I will swap that plug again. I have an extra, and a spare coil, so I guess I can try them. Luckily its not the one under the manifold at least.

 

[walterjay]

My 07 Tucson has iridium plugs. They went 180,000 on the factory plugs.

 

[jsean]

Plugs look good! Some contortion and utilization of extensions, wobbles and universal joints is the way to go on these. Doing it the book way is more time consuming and risky as you said.

Didn’t have any coils go bad on me when I did mine at 105k. Plugs looked about the same, but I think my passenger side plug threads had a tiny bit of oil on them. My replacement plugs were the ruthenium ones off RA.

 

[benjy]

seen a great youtube to do plugs without removing manifold!! my 2011 VQ40 fronty has 55 thou on the OE plugs + thinking about changing them. girlfriends vw passat 1.8T had 50 thou when i changed the OE ones, they looked good BUT a 2 mpg gain told another story because even slightly rounded center electrode DONT fire as good

 

[Oliveoil2]

By the looks of the plugs you’ve got a clean running engine.

 

[tbm5690]

This is another example of why I doubt I'll touch any plugs prior to 150k. Iridiums last forever. My VW specs 40k mile intervals on iridium and when I pulled them recently they looked brand new. Prior to that I pulled a set at 160k that looked perfect.

 

[SC Maintenance]

This is another example of why I doubt I'll touch any plugs prior to 150k. Iridiums last forever. My VW specs 40k mile intervals on iridium and when I pulled them recently they looked brand new. Prior to that I pulled a set at 160k that looked perfect.

Its really hard to tell. If you run the plugs too long then it becomes really hard on the coils - they require more voltage to jump the gap and the coils run hotter. Not to mention more chance of them getting stuck in the head.

These plugs look OK, but the center electrode and the top part of the bottom electrode were far from perfect. Doesn't really show up in the photo. Could I have run longer -sure, but I am happy I changed them.

 

[GMBoy]

Its really hard to tell. If you run the plugs too long then it becomes really hard on the coils - they require more voltage to jump the gap and the coils run hotter. Not to mention more chance of them getting stuck in the head.

These plugs look OK, but the center electrode and the top part of the bottom electrode were far from perfect. Doesn't really show up in the photo. Could I have run longer -sure, but I am happy I changed them.

That is exactly right. Running plug longer stress coils more. You won't feel it and think everything is fine. I like to do slightly before the recommended intervals because the recommended intervals are really based on driving styles most don't do so cut the time a little short to be safe. If it's recommended to do 100k I like to do it at 75-80k.