How to - Change spark plugs VQ35HR (MY07+)

[AK350Z]

Hello folks, thanks to recent messing about with spark plugs, I have created a guide for changing the spark plugs on the VQ35HR engine found in the Model Year 2007+ 350Z.

 

This Guide is for the 309BHP HR engine, not the VQ35DE and rev-up engines found in 2002-early 2007 Zeds. The later engine is identifiable by the twin air intakes and the humped bonnet.

 

Please note the spark plugs in the HR engine are smaller than those in the DE and Rev-up, M12 threads versus M14. The HR engine also has Irridium plugs as standard!

 

Should you need the guide for the earlier engine, Ming has already covered that base here: http://www.350z-uk.com/forum/viewtopic.php?f=35&t=4021

 

First things first. Tools. You will need:

 

14mm deep socket with a magnet-on-a-stick or 14mm spark plug socket

10mm socket

5mm Allen Key

Needle nose Pliers

30mm spanner (across the flats) or big adjustable spanner.

Phillips screwdriver

 

A well stocked 3/8ths socket kit should cover most bases.

 

Your HR engine should look a bit like this:

 

 

Note the large plastic cover that obscures all the bits we want to get to. To get past it to the oily bits, we first need to remove the strut brace.

 

To aid refitting at a later date, I drew a line with a permanant marker so I could retighten the nuts to the same position.

 

 

Slacken off the two outer nuts of the three with your spanner or big shifter (If you're rough like me). These are the lock nuts that stop the brace undoing itself. The left-hand nut turns toward the front of the car, the right-hand to the rear. Let them off a couple of turns.

 

The center "nut" needs to be slackened off to take the pressure of the brace. I found two whole turns to be enough, turning towards the back of the car.

 

Remove the plastic cable clips from both ends of the strut brace.

 

 

Take your 14mm socket and remove the 4 bolts at each end of the strut brace.

 

 

 

Remove the brace and place to one side.

 

Next, the engine cover. Take your 10mm socket and undo the 4 bolts first from the front, and then the rear part of the engine cover.

 

 

Bare naked plenum! No chance of a nice shiny polished one here.

 

 

Next up is to remove the intake piping from both sides of the engine. It looks complicated, but you only need to undo a couple of clips and screws to take the whole lot out!

 

The removal can be simplified by popping the trim clip of the air scoops in the front panel. This lets you lift out the intake easier. Remove the two small screws from the air sensor and carefully place to one side. The air box is held down with one screw in a vibration mount. (All in red below)

Squeeze the spring clips and remove the two small pipes from the intake, in yellow below.

 

 

Undo the Jubilee clip (Blue below) on the throttle body and wiggle the intake pipe off. The whole assembly will now lift out.

 

 

The left hand intake is pretty much the same.

 

Undo the 4 5mm allen bolts from each throttle body and cable tie the body out the way.

 

 

 

Take a 10mm socket and remove the bolts from the three coil pack plugs on each side, unclipping the cables. The rearmost ones shouldn't be too tricky as the obscuring pipes can be bent out of the way.

 

 

 

Next the trickiest bit! The spark plugs on the HR engine are small and deep set. A 6" extension for your wrench is necessary, as well as decent thin walled 14mm socket. If you don't have a spark plug socket with a rubber insert to grab the plug, you can improvise with a magnetic probe or screw retriever, or maybe some ghetto style blu-tack stuffed in a socket!

 

Once all 6 plugs have been changed, all you have to do is put everything back in the reverse order you took it off. Don't forget to tighten both ends of the strut brace down before tensioning it back to its original position.

 

Easy as pie! Please feel free to correct me if I've made any errors.

[lrh]

Good guide and pics

 

But unless you bolt the strut brace down in exactly the same position as before, lining up the nuts won't apply the correct load to the bar. The manual says tighten the centre bolt 660° or 1.7 turns.

[stanski]

Excellent guide Andy - this is the sort of pic heavy guide we like - makes life a lot easier

[Beavis]

Nice work Andy

[smudga]

Andy,

 

As above a good guide as have just done the same, but I have a suggestion or two...

 

1. You don't need to remove the strut brace. The plastic cover is in 2 halves and can be removed with it in place. Also the filter housing & pipework up to the throttle bodies can be slid out from under the strut brace.

 

2. Just disconnect the wiring plug from the MAF sensor & leave it in the housing as this will stop it getting any dirt in it or being knocked in the engine bay.

 

3. Disconnect the wiring plug from the throttle bodies and the two pipes and they can then be removed completely from the car, again just to help keep any dirt out and to save twisting the pipework too much. these 2 pipes do have coolant through them so be prepared for a little dribble or two.

 

4. With the strut brace still in place as long as you have a 3/8" socket set with a 6" extension bar you can still get th the foremost plug on the nearside of the car.

 

I'm not being critical as without this guide I wouldn't have known where to start, but just thought that my experience may help others, as getting the brace back in place can be a pain.

[ZMANALEX]

Great job Andy, superb guide:

[Mavrik]

Anyone know the Denso product code for these 313 HR plugs?

 

EDIT>: The Denso plug product code is FXE22HR11...

 

Thanks for the guide AK350Z

Edited April 22, 2017 by Mavrik

[SHEZZA]

Anyone know the Denso product code for these 313 HR plugs?

 

I should think most traders on here could supply the plugs. Maybe try a PM or two. Here's one for example.

 

http://h-dev.co.uk/product-category/350z/service-parts/?v=79cba1185463