Mouser

A Few Tips For Changing Spark Plugs

Recommended Posts

I did a spark plug change at 60k, following the usual pdf guide and thought I'd share some tips.

Remember to disconnect the Battery first. Note that doing so will cause a self check on the next start up and clear your MPG records. The first start also takes ~ 0.5 seconds longer, so hold the start button down else it may stall and you'll panic!

The 5mm allen key you need has to be a long thin one, multi-tools & socket sets are no use here. Don't get the useless ones with a ball on the end. Use a pair of pliers / mole grips to gain leverage if necessary. The one closest to the firewall is the most difficult of all, so do that first, then the one in the centre so that they are under the least load (less torque to undo them).

Have a nice strong magnet to hand to help draw bolts out (attach to screwdriver) so you don't drop them.

A 10mm ring spanner is essential for removing the bolt on the side of the throttle body unless you want to be frustrated. Also make sure you have a good 10mm socket and 10mm long socket, same goes for 12mm. Always make sure you know which way loosens and which way tightens when working in awkward places.

Removing the Battery and the case completely it's in might seem fiddly, but the improved access to the bolt at the rear of the intake manifold makes it well worth your time.

The spark plugs are down a deep (20 cm?) hole, so your socket extension needs to be long enough for the job. 16mm magnetic spark plug socket is what I'd recommend.

The large jubilee clip on the air intake hose may need some jiggling to relax its grip once you have loosened it.

The passenger side rearmost spark plug has something grounded kind of in the way, loosen that to rotate it out of your way, it's torqued down very tight from the factory, make sure it's gud'n'tite when you tighten it back up as well.

The spark plug connector is easiest to loosen using a fine flat screwdriver rather than your thumb. Insert from the spark plug side (not the wire side) under the catch and gently release it by lifting that side up a mm.

Undoing the 10mm nuts holding the plastic wire housing which routes to the spark plugs makes access much easier. Even if it's not obviously necessary. It's obvious how it goes back on, and you're not going to cross-wire your plugs.

What might you forget to do back up? The jubilee clip on the air intake; the clips which secure the vacumn hoses to the intake manifold; the bolt that secures the intake manifold to the engine block; the nuts on the Battery; the hose holders which help with routing and secure hoses to the intake manifold / air intake; the wire which connects to the air intake; the Battery sensor on the side of the Battery case.

Overall the job is very easy if you use those tips.

Share this post


Link to post
Share on other sites
 

Nice one Mouser....I'm sure that will be valuable to a lot of people.

Seems like a comprehensive guide.

You could put that in the 'How To' guide area for the is 2005- Onwards

here

http://www.lexusownersclub.co.uk/forum/tutorials/category/6-lexus-is-2005-onwards/

Share this post


Link to post
Share on other sites

Thanks so much. Great job putting all tips together.

Share this post


Link to post
Share on other sites

Additional tips:

Get a surge tank gasket set (3 sets of 17176-31050) and a throttle body gasket and do the them at the same time.

Don't use a ball allen for the cap head screws. I snapped a ball off down a long tunnel, but the ball got trapped because it deformed the screw head. I ended up having to epoxy a slightly too small socket to the bolt. The best tool is a 1/4" socket set with hex bits and a 15 cm extension bar - this works perfectly.

If the spark plugs don't turn completely smoothly on the way out, send a rag on a stick down the spark plug hole to clean up the threads. You don't want to be tightening a plug into a carboned up thread.

I couldn't get the behind throttle body bolt back in at all. The manifold is pretty solid, and there are plenty of bolts in, so I didn't try too hard as the bolt is pretty much superfluous and it'll make the job easier next time.

In case you lose any bolts, remember that ISO M8x20mm bolts have a 13 mm head, but Japanese 8mm bolts have a 12 mm head - same bolt size, but different spanner. I lost one on the under tray, I did search for it and try to get it with a magnet, but couldn't find it. Worth also having some spare M6x30mm zinc cap head screws in case you damage or lose one.

Share this post


Link to post
Share on other sites

Additional tips:

Don't use a ball allen for the cap head screws. I snapped a ball off down a long tunnel, but the ball got trapped because it deformed the screw head. I ended up having to epoxy a slightly too small socket to the bolt. The best tool is a 1/4" socket set with hex bits and a 15 cm extension bar - this works perfectly.

That's why I said "don't get the useless ones with a ball on the end". I tried with my socket set allen keys, but the one at the back isn't reachable using those. They're not torqued all that tight fortunately.

Toyota advise that it's not necessary to replace the gasket, unless you notice or cause damage, even though it's listed as a non-reusable part.

Has anyone ever found a good use for the balls on the end of allen keys? I tend to find they're only useful for getting stuck in nuts and requiring a powerful magnet or epoxy to remove.

Share this post


Link to post
Share on other sites

Thanks for a great guide , it's a job I've been putting off cos it looks like a lot of work ! A couple of questions if I may , are the manifold gaskets easly available ? Is it really necessary to change them ? How long would you say to complete this job ?

Allan

Share this post


Link to post
Share on other sites

Mouser, As Allan said in the above post - I have been putting it off but will do it at some point. I believe there are 6 gaskets in sets of two, so 3 are required. I have read on other forums that they do need to be replaced when changing the plugs but like you said - if not damaged do they really need to be?

Did you replace yours when you done it?

Share this post


Link to post
Share on other sites

If you want to be confident you won't need to change them, then order a set in - a nearby Toyota/Lexus dealer should be able to help you with that. My nearest advised it's not necessary unless damage is found, so I didn't.

Share this post


Link to post
Share on other sites

Mouser, As Allan said in the above post - I have been putting it off but will do it at some point. I believe there are 6 gaskets in sets of two, so 3 are required. I have read on other forums that they do need to be replaced when changing the plugs but like you said - if not damaged do they really need to be?

Did you replace yours when you done it?

The service manual says they need changing. I didn't change mine, despite what I said earlier, because I didn't have them, and didn't really know what I was doing.

The issue is that if you damage the gaskets when taking the manifold off, then you've got a problem if you don't have spares. They're not expensive, I think something like £5 a set from a dealer.

Share this post


Link to post
Share on other sites

Great tips, it seems the fuel line needs to be disconnected from the manifold, so does that mean we need to change the crush washer on the fuel line and what torque do you re-tighten to?

Share this post


Link to post
Share on other sites

Also, do the O rings underneath the manifold need replacing? These rings are rather expensive to replace almost £30 for a set of 3.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.