120k mile service coming up ...

[szh]

Hi, all.

In a few more months, I will need to get the 120k service stuff done on my 1995 Infiniti Q45. I have relied on the Infiniti dealer doing the work in the past, but I kinda feel that they tend to do more than is necessary or required.

I have read the Q owners manual listing for the 120k service, but, in the opinion of people here, what is the real list of items I should have taken care of? Car is running pretty normally, except for:

1. Suspension (struts and upper links), which I am hoping to DIY soon.2. Needs new tires - also within a few weeks.3. Slightly noisy fuel pump - I may DIY, if I can find the time some weekend.

These three above are all stuff distinct from the 120k service, of course, so I will do them (or get them done) separately.

Thanks!

Z

[elwesso]

A complete list of things that you should do would be as follows:

PlugsRear diff fluidcoolant flushtstatplenum cleaning/tbPS fluid changeinjector/transmission flush (if it hasnt been done already)

That covers about everything I can think of...... If you are planning on pulling the plenum, do a search, as there are tons of other things to do with the plenum job....

[elwesso]

Also, the fuel pump (as I hear) is DIYable..... I have been in there, and it doesnt look too bad...... Maybe a couple hours at worst.......

[szh]

Thanks, Wes.

On the rear diff fluid ... replace or top off?

I did the PS fluid change recently. Also had the transmission double flushed with Mobil 1 Synthethic ATF (and pan drop plus filter replacement in between flushes) about 5k miles ago (just before the replacement transmission warranty ran out), so I don't intend to do these again this time.

To change the plugs, does the plenum need to be pulled? If so, that would be an excellent time to do the plenum cleaning, I would guess! I forgot to ask the dealer to do the cleaning when I had to have leaking head gaskets replaced some months back! Argh ...

Z

[elwesso]

Rear diff........ The plugs take a 1/2 in drive (square), and you undo the bottom one, and let it drain...... I didnt warm it up first, but that would probably be best...... Let it drain for a good 20 mins, and while its draining take out the top plug (its on the top, drivers side of the diff) and clean it out........ when its done draining put the bottom plug in...... Youll need 2 quarts of 80w90 gear lube...... The board recommended mobil 1 synthetic, but i couldnt find it so i used valvoline synthetic..... I got a pump thing that screws on to the top of the bottle, and that makes things 10000000000xs easier, since there isnt enough room to get the bottle up there..... Youlll pump a quart and a half into the diff, and its full when it starts coming out of the filler hole...... Make sure you clean off both drain plugs really good, especially the top one....... Then tighten both plugs to roughly 40-50ft/lbs......

Plugs- described in 5 words: straight-foreward, but no fun....... The plenum doesnt come off, and taking it off wouldnt make it any easier....... Simply take off all the allens on the black covers, undo the ignitor pack (the box with the 2 plugs on top of the black cover)..... Once you get that off, you will see the individual coils..... I took off all of the coil wires and moved it aside, as it makes things easier...... There are 2 bolts holding on each plug...... undo those and pull the coil out....... Youll need a good extension to get down there to undo the plugs..... undo, and then replace...... Its really easy.......

If you are concerned about plenum cleaning (and not underplenum hoses), just take off the TB and clean it out, and the inside of the plenum.... If you cant do it, have someone reach in there with really skinny arms reach in there and get it as clean as possible........

[greg_atlanta]

If you are sure plugs were replaced with OEM plugs at 60K then you can probably wait another 20K miles.... they do last a long time.

[szh]

Hi, Greg.

If you are sure plugs were replaced with OEM plugs at 60K then you can probably wait another 20K miles.... they do last a long time.

I seem to remember that I had the Infiniti dealer do the spark plug replacements at 60k miles - I assume they used OEM plugs (but I will verify this ... both that they did the work and that they used OEM spark plugs). I was planning to replace them again at the 120k mile point ... rather be safe than regret it.

Z

[elwesso]

The plugs could probably last the life of thecar. mine werent too bad, and they were the origional at 120k

[90Q45blue]

With 251,000 miles on my car I can definitively say that the plugs will not last the life of the car. OEM's are recommended to be replaced every 60k but probably could last 100k. The fact that your's seemed ok at 120k is a rarity; however, just because they look ok doesn't mean I wouldn't replace them. For only $66 from Joe for a set it's not a bad deal and the results of worn plugs or non-OEM's are pretty significant. For an example see BIONICQ45's thread on his car troubles.

Nick

[elwesso]

Again, true..... Id go ahead and replace them at the 120k service interval, regardless if they "need" it or not....... Sure, they may be OK, but i wouldnt go too long.......

[Q451990]

As much as anything, I think the 60K rate is to to make sure the threads don't seize! Dennis has told horror stories about terrible noises taking out high mileage and old plugs. I'm scared to death that Q2's 13 year old OEM plugs will be a problem, but hopefully it's the heating cycles that seize the plugs, not age. I always use an antiseize compound on plug threads. My dad had to use a large impact wrench to get plugs out of our old 82 Mazda 626 back in the day. Destroyed some of the threads, but I think there was enough left to get the new plugs back in. In any case there hasn't been a Roberts-installed spark plug without antiseize since!

Heath

[elwesso]

Yea, I remember some of the noises my plugs made when I took them out....... I had to use a 2ft breaker bar to get them undone.......