Hi,

Now have 114,000km so it's time to change the spark plugs on my Magna, 2004 TL. After getting a quote from my local dealer I'd like to save the $220 labor cost and put it towards buying some tools and do it myself as I have the time to learn......... plus need some tools anyway as have recently immigrated to this fine country.

He quoted an additional $105 for the 6 plugs but I can get them from Super Cheap Auto or Repco.

3 on the front seem straight forward but found out that the 3 on the back are platinum and well hidden by the intake manifold

Watched this quick movie clip of what to remove to take off the manifold so can follow it no problem https://www.youtube.com/watch?v=iUhJd2L3BZs. I also noticed in another post it mentions to mark the position of the accelerator cable attachment before you remove it and that the gasket is made of steel so is reused

The dealer also mentioned that it may take longer for them to work on it if the rocker seals were worn and oil was leaking into the plug chamber so I'd like to be prepared for the worse should the chambers be oiled up.

Can anyone please advice me on which seal to purchase before I start? I'd rather have it handy so I don't have to remove the manifold twice.

I really would like to do this job myself and have the Max Ellery manual to refer to if things get wild but if you think changing the rear plugs is not for the novice then I will bite the bullet and get the dealer to fix it.

Many thanks,

Andrew

Go to any auto parts store & ask for a rocker cover gasket kit for a 6G74 Magna engine. The kit will come with the spark plug tube seals.

Cheers

Thanks for the reply. After you mentioned the gasket kit with tube seals I looked more into it all and can get the parts no problem. Also it's been quite interesting / entertaining reading this forum about changing the gaskets but doesn't look impossible for me to take on.

Looks like I need some sort of extension to get the plugs out as they are way down inside so will check to see what's available. Will also look into seeing if the manifold needs a gasket also as that's certainly coming off.

An extension to grab the plugs isn't necessary, if your plug socket has the rubber insert it should pull the plug out. Alternatively you can use a plug lead, pushing it onto a loosened plug to lift it out. Putting them back in is a bit trickier if your socket's lacking the insert, but it is possible to use a lead for this too if you fit the plug in loosely so it drops off with a bit of a wiggle. I believe other members have used a short length of garden hose to good effect as well, so long as it fits nicely over the insulator.

Re the manifold, you only need to remove the plenum chamber, not the whole manifold, so you'll just need the manifold-to-plenum gasket. Also worth grabbing the plenum-to-throttle body gasket as well. On that subject, the throttle body need not be removed with all the associated disconnecting of things, the bracket up the back supports it independently of the plenum chamber.

You'll need a torque wrench that's capable of low settings, most don't go low enough for the valve cover bolts which need to be pretty accurately 3 to 4 Nm to avoid leaks caused by too loose or too tight bolts (too tight warps the cover face causing leaks). I believe Supacheap Auto stock a little 1/4" torque wrench that can go that low. You might also need to re-gap the groove in the cover into which the seal pushes. If the new seal, once pushed into the cover, falls out when the cover is held up gasket side down, tighten the groove where the gasket doesn't hold in by gently squeezing with pliers, slightly bending the inner flange of the groove in. Don't be tempted to use any sort of sealant on this gasket, or any of the others.

Thanks for the extra info. I'll get some tools this weekend and have a go.

From memory, if you want to do the spark plugs, you need a 16 mm plug spanner, not the larger (21mm?) one. The cheapie socket sets sometimes have both sizes, sometimes only one. Check and get one with the smaller plug socket - preferably one with the rubber insert as well.

An extension to grab the plugs isn't necessary,

If your plug socket doesn't fit well - like my own, Most of cheap crap parts auto stores (and better stores) have magnetic pickup tools - the one I have is telescopic - Spark plug tops are easy to pickup down a recessed bore as the tops are very metallic, you can even lower the new ones down with a bit of a flick to leave them behind and then use the plug tool to tighten.

I have said it before, but it is worth repeating now. When you do the rocker cover gasket, do NOT use sealant. I had a 6G74 engine rebuilt and the guy used heaps of silicon everywhere. After 3 km, I had to have the engine totally stripped again and there was oil in 3 of the 6 plug tubes, despite having fitted new tube seals. The original design allowed for slight compression of the tube seals and additional sealant should not be necessary.