DIY Spark plug service tomorrow - Plugs, Seals & Leads.

[jace]

Hi all,
Tomorrow (start of the Easter long weekend - just in case it goes wrong and I need time to fix mistakes!) I'm going to change the spark plugs and repair some leaky spark plug seals on my 2000 NM paj.

I will have to take apart the intake system to get at the Valve covers which makes this the biggest job I have attempted with this (or any other) car.

Going off details from my Haynes book I will remove the air intake stuff, kill the pressure in the fuel lines (by un-plugging the relay and running the engine till it dies), drain the coolant, remove the intake system, open both valve covers (rocket covers), replace the spark plug tube seals (tiny little things like glorified O rings that cost me $18 each!), replace the valve cover gaskets ($40 each thanks very much MM), replace the spark plugs ($148 for the set!!!), replace the leads (wait for it...$169!!!!! 'Trade price') and rebuild.

The rebuild will include a new air intake gasket ($21) and new coolant ($41).

Sorry about the whinge but I am pretty sure I just paid over $550 to replace my spark plugs.

Any rate 2 things.

Firstly I would really appreciate advice from anybody who has done this job before (the little things I should watch for etc). I'm sure it is one of those jobs that is simple when you have done it once but there is always a first time and it's all a bit daunting right now.

Secondly, because I am sure there are other Pajero newbies out there who would like to have a go at their own plugs, I plan to take photos and make up a how to sheet when it's all done. I'll let you all know when this is done.


As always thanks for any help.

[Matatak]

some quick things i can tell you.

You WONT need to touch the fuel system.
Theyre called RockeR covers . (or Cam covers, or Valve covers etc....but not RockeT covers)
There is 2 bolts on the Lefthand side (Passenger side) of the manifold securing it to the head which need to be removed.
8 bolts at the kind of middle of the motor securing the manifold down which are different lengths so keep them in the right order.
the bolt at the back of the manifold is small and can be fiddly, and try not to drop it
2 bolts securing the fuel lines onto the manifold.
Various brackets for electrical connections that need to be undone and moved out the way.

I Leave the coolant lines on and secure (tie) it up out of the way to get the plugs under it then move it to the other side and do likewise

The Lead order is written on the manifold itself in the order the leads plug into the coils.

trying to think of more for ya...

[psproule]

I did mine on the older NM without completely removing the manifold. Just unbolted and removed enough to lift it up about an inch and I was able to get at the plugs. From memory the fuel line came off and a couple of Vac hoses but I didn't touch the coolant lines.The inlet gasket is stainless steel wafers so I didn't replace.

Why are you removing the rocker covers? Are they leaking? The plugs come out with the rockers in place and it is a whole lot less messy. I cant understand why the Haynes manual would tell you otherwise.

[mrbitchi]

Yes. No need to replace the plug seals. Never heard of them leaking..

[jace]

I have to open the Rocker covers (not Rocket - silly me) because 2 of the oil seals are leaking on the left hand side (I figure I will do the right side as well to prevent the same happening down the line). That is causing oil to leak from where the leads go down into the cover.

The parts guy at MM said that the seals are a common issue and that he has a monthly standing order of 24.

The manual does not suggest removing the covers if you are just going to change the plugs.

Just about to make a start now - thanks for the tips.

[mikey]

Yes. No need to replace the plug seals. Never heard of them leaking..

they are always leaking, i work at mits and nearly every nm paj has leaking tube seals, we do at least 1 a day

[mrbitchi]

they are always leaking, i work at mits and nearly every nm paj has leaking tube seals, we do at least 1 a day

Fair enough. Not something that's been raised on the forum but...

[dolphin]

Jace, it would be nice if you could either show us a pic or measure the actual size of these sparkplug 0 -Rings . reason being if there a suitable size that VITON manufactures , the cost per 0 - ring would be well under half the MM costs of $18 ea. for any guys that arn,t familular with this product VITON, they supply the best O -Rings availble that withstands excessive heat etc etc , so good there used as a coupler / isolator on high performance race 2 and 4 stroke engine / pipe systems.

[mikey]

Jace, it would be nice if you could either show us a pic or measure the actual size of these sparkplug 0 -Rings . reason being if there a suitable size that VITON manufactures , the cost per 0 - ring would be well under half the MM costs of $18 ea. for any guys that arn,t familular with this product VITON, they supply the best O -Rings availble that withstands excessive heat etc etc , so good there used as a coupler / isolator on high performance race 2 and 4 stroke engine / pipe systems.

we have used the non gen ones before are they are too small
it is worth paying the extra for the genuine ones, same with rocker cover gaskets use genuine

[gaz1]

Oh goody, something else to keep an eye out for! Mikey what are the obvious places we V6 owners should check for signs of leaks from these 0-rings? Does it just appear at the top of the rocker covers or show up somewhere else?

Cheers

Gaz

[mikey]

you just pop one of the easy to get to ignition leads out and if it has oil around it then u know the tube seals are leaking, if they are leaking bad, u also gotta replace the leads cos they swell up

[jace]

Spark plug tube seal details:

They are about 42mm across the top.

I have attached one pic of the seal and one of them installed on the tubes. They slide over the plug tube (fairly snug) and then the rocker cover completes the seal.


I have finished the job now. It took me about twice as long as I expected but no real issues other than breaking one of the electrical fixture bolts - annoying but no big deal.


I was surprised at how bad the seals were. Judging by the oil leaks I assumed that there were 2 on the left that had failed and I was doing the full 6 as a precaution. It turns out they were all failing to one extent or another and on 2 they had leaked enough that the spark plug was sitting in oil. These were both on the right which I thought were fine (no external leaks were visible).

The plugs were very worn. I suspect that they had not been changed for quite some time.

The leads definitely needed the new set as well. Apart from being generally deteriorated they had also swollen where they joined the oil seals (essentially they had been soaking in oil). In some cases they had expanded so much they had broken their seals and were sitting 3-4 mm above the rocker cover.

Anyway she is all back together now and chugging along happily. I was expecting a minor improvement in engine performance and was happily surprised at the extent of power gain achieved by the exercise. I also expect a small improvement in fuel economy.

I took some photos as I went and will post a bit of a guide over the next few days.

[gaz1]

Good info, Jace.....more pics will be good. Did you have to renew the intake manifold-to-head gaskets? I noticed Pat Sproule mentioning he didn't need to replace them.

Bloody big parts list!

Gaz

[jace]

Gaz you could probably reuse the gasket if you used a bit of sealer - They are metal so clean up ok. I did this for the gasket that joins the upper and lower parts of the manifold - just added gasket sealer to both sides.
But personally I would replace the main one (that joins the manifold to the head). If only because it is such a pain to get to in the first place. The new gasket has a slightly raised section that would compensate for some difference in pressure - they are flat as a tat when they come out.

I have put a pic of the two sections I am talking about but didn't take any of the gaskets.

I'll put a full sequence of pics up shortly.

[jace]

Here is the full set of pics from the operation.

1 - the parts list: Leads 1 set, Plugs x 6, Rocker Cover gasket x 2, Tube Seals x 6, Inlet Manifold Gasket x 1, Coolant concentrate (Ignor the transmission flter and ATF - ther're next!).

2 - the engine before the work.

3 - the issue not the best shot but you can make out the oil leak on the valve cover and the slightly raised lead.

4 - the engine after I have drained the coolant and removed the battery and filter box.

5 - the electrical leads with my labels on (to make sure I connect the right plugs when it's time to put it back together).

cont.