Spark Plug Change

[MLW]

2002 LS430.

Did a service today and did the spark plugs.

I am very experienced on cars, but it is a tricky job and took two hours in all. The passengers side is worse because of limited space, the drivers side is better when you remove the air filter box and the other black box above it (3 bolts and some rubber pipes in all). You can then swing it upwards and all 4 holes are revealed. See photos.

A few points.

Get a 3/8 socket set with two extensions (long and short) and a universal joint. It really is a contortionist nightmare. Can't see how you can do it otherwise. I have a Bahco set which is fantastic. Best £33 you will ever spend. https://www.amazon.co.uk/Bahco-S330-Socket-Piece-Square/dp/B0001JZRYY/ref=sr_1_1?ie=UTF8&qid=1537888968&sr=8-1&keywords=bahco+3%2F8+socket+set

I removed 4 of the coil packs with the wires still connected. This seemed less brutal than pulling them off. The 4 wires that go into the connector are very thin. I was terrified of snapping them as I tugged them off. A new loam looked on the cards.

Do not cross thread. I took Denso's advise and did not grease the threads. The all came out easy but you MUST gently ease them in by hand for at least 3/4 way up the plug thread. There is quite a lot of thread on it. Put them in dead square, back turn till they click, and then screw in by hand.

Use a good torque wrench. You cannot see anything, so although I usually 'feel' the torque, I was so scared, I bought a great £44 Teng low torque wrench. I have wanted one for a bit, and it was critical to getting 22 Nm. The washers can be felt scrapping the head as you screw in by hand. It then seems like you are over tightening, so must use a wrench as it is surprising how the washers give when compressed. Also, when it clicks, you feel good!

The most difficult is the front left one by the dipstick. There just isn't any room to get the coil tube out. Eventually by carefully 'bending' the dipstick tube away and rotating the coil you can JUST get it out and back in. But I was terrified of snapping it. Anyone know a better way?

Snapping all the wires and tubes under there, is a constant fear anyway.

Took the car for a test drive and although it is probably physiological, it did seem very smooth and pulled great. Fuel economy thoughts after more miles.

Get good genuine plugs. There are a lot on eBay that are very cheap, and look iffy. I got mine from Opie Oils, (made in Japan) at £51.51p including delivery and a bit of on-line discount. Not bad for iridium plugs that should last another 60,000 miles. Don't want to do this job for some years, although I would be quicker next time.

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[steve2006]

A little tip...when refitting the new plugs and to avoid cross threading I used a piece of rubber tubing that can be fitted over the nipple on the plug. Gently lower the plug into the head and then twist the tubing to start off the threads and screw the plug in as far as possible with the tubing. Once safely threaded pull off the tubing and fully tighten the plug to the correct torque.

[MLW]

A very good tip. However I found these plugs to be very deep and having a metal 'linkage' gave the process 'feel and gentle purchase'. However, it must be done by hand. In an Austin A40 with an iron head total observable plugs, it was all so much easier! 4 plugs changed in 20 mins top.

[plexus914]

Regarding Removing Spark Plugs:

- Remove spark plugs on an alloy engine only when engine is cooled down.

- Do not use anti-seize on spark plugs. Put them dry back in.