Can anybody say what has to be done to R&R the plugs next to the firewall on a V6 3.0L? Car is an '03 6.

Related question: is there a service manual for this engine and car? Where do you get these, and how much? are they worth it?

Would love to have the Haynes book for this car, but believe they have not made one.

 

I have mastered the fine art of replacing the headlight bulbs on my V6 6 5spd. It is not easy, and you have to be pretty adept at working strong tiny spring clips that you cannot see w/ bare fingers But once you "get it" it can be done. Note: the air filter box on driver's side comes out easily enough (loosen the hose clamp on the intake, and the wire connectors, and pull -- it comes right up), and that extra room aft makes the job much easier, although not absolutely required. As to the other lights (turn signal and running/parking lights) I have no real clue, especially on the rt side. I'm guessing you can R&R the windshield washer tank, and that would help a lot, but not sure that is an easy job. Have not given it a proper go yet, electing to ask here first. I have seen some posts about taking off the bumper !!!, and holy sh** Batman, are you serious? For the stinking bulbs? Anyway, someone here has certainly tackled this from a sane point of view. Or I hope so. Any pointers for how to do this w/out dismantling the front of the car, on either/both sides, will be much appreciated.

 

this last part was supposed to be a new thread, but I am a rank newbie here, and have not got the system down yet.

However, if you know the answer, pls say . . .

 

You should remove the intake plenum to change spark plugs by firewall. Disconnect ground wire on battery (it also will re-set your ECU which is required with all the changes you are about to do). Remove cosmetic piece of plastic engine cover.
First remove Mass Airflow Sensor, then accordian tube (inspect for cracks), then throttle body (now would be a good time to clean MAF and throttle body).
Unbolt EGR valve, carefully remove wire harness attachments from intake plenum, loosen bolts from plenum (they don't lift out, they stay with plenum). Clean plenum.
When re-attaching please change the following gaskets/seals:
Mahle W0133-1807640 Throttle Body Gasket | Auto Parts Warehouse
OES Genuine W0133-1639826 Intake Plenum Gasket | Auto Parts Warehouse
Rough Idling Issues |*MotorWeek is a video on how to clean throttle body (since you have battery disconnected no need to worry about it moving and depressing gas pedal).
PICS are from my 2006 car: Mazda Forum - Mazda Enthusiast Forums - UseYourNoggin's Album: Intake Plenum & PCV Valve. 2006 Mazda 6 V6 3.0 ltr.. Good time to change PCV valve as well (easier now with plenum removed). Inspect vaccuum lines.
Ignore my throttle body gasket as it is an extra one due to my Steeda throttle body spacer (yours does not look like it, click on link supplied)

 

Dear UYN,

Txs very much for the details. My '03 and your '06 likely a little different, but maybe not enough to negate the message as a whole. Great pictures, BTW. Clearly not a 1/2 hour job. Car has ~70K mi. and I figure it might be time. I have no complaint about how the car runs, starts or any such thing at present. But figure plugs need to be swapped out somewhere along the line. What do people usually get out of Ir tipped plugs, anyway? Plus I get a MAF clean and PCV update out of the adventure as well. Should I put this on my to-do list, or just wait until trouble shows up? And the next obvious question: Is there a clear favorite for brand/style of replacement plugs? At this point, I'm going to say that considering the trouble this would be, money for plugs would not be an obstical (?). Your opinion?? And what would be a reasonable charge at areputable shop for thsi sort of service? Normally, I am DIY all the way, having wrenched more than a few cars over the years. Just curious.

 

Stick with NGK plugs. I believe they are OEM. Iridium plugs are a bit hotter but do not re-gap them (heard iridium is not good when re-gapped).
I would definitely change the PCV, clean MAF & throttle body since it is accessible easily. Inspect all Vac lines. Possibly even clean EGR (it's partly off & accessible).
Some people would not change, however I personally think there is enough mileage. Your pre-cats depend on a good running car. Once problems start (like misfires, bad PCV) then pre-cats are more of a concern because they don't like oil or misfires. Change the throttle body seal & plenum (6) seals. This is preventative maintenance to ensure a good running car. Driving around with problems, and waiting a week to get it properly looked may cause damage (I am not a believer in that especially for these items).
I actually did the work myself. I would say 2-3 hours max. I did not torque bolts down, but did not overtighten them either (hand tighten).
Do not remove throttle body from engine, unbolt it clean it, and let it hang there catching all the fluid with paper towels (do not force moving it).

I would also do this while you are there: EGR Modification/Optimization: - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum
At the bottom of the first post it also does give you torque specs.
It also gives you step by step instructions on intake plenum removal.

 

Like this:

How to replace the spark plugs on a 2005 Mazda 6s sport - YouTube

 

More data: recommended plug is w/ platinum tips. Service interval is 90K mi, they say. There is a T fitting from the radiator w/ coolant in it, small rubber tubing runs low right near the side of the battery. Advice is to be very careful here disconnecting as is easy to break this plastic thingy, and then you are back to buying more parts.

So the story is a shown by UYN above: take off a whole lot of stuff from the engine top, and be careful doing it. You gotta dig for those three plugs.

 

That thingy is why you are to be careful with throttle body, not forcing it to move.

 

Why in heaven's name do they design vehicles like this? This is how Fiat's used to be built.
Sure, wanna change plugs, or replace a timing belt? No problem. Do you want to remove the engine first, or should I?

I have NEVER understood this kind of engineering. That's more trouble than working on an old British Leyland sports car... which I used to do. 'Got a lot of bloody knuckles doing it too.