QX 4 ?'s

[skinnyphatman]

I purchased a 1999 QX 4 earlier this year with about 95K miles on it. I took it in to have the timing belt chanted (105K service) and it turned out I needed some additoinal work, pretty expensive. I needed to have the breaks re-done, and bearings re-packed along with the timing and other belts. In addition to that, they recomended that I do an induction flush to clean the fuel injectors and flush the transmission. The shop said I could probably wait a little on the last two and since the other items totaled a nice sum, I deferred the indiction flush and the transmission flush.

Now, time to pay the piper... I am interested to see if either or both of those services are something I could do myself. I am pretty handy and with the right tools and good directions, I am confident with most anything (short of major engine work).

The induction flush appears to be more than a quart of STP or other additive in the tank. I saw a show on DIY where they did a flush and it appeard pretty simple with the right stuff (although it was on a Tarus). Basically disable the fuel pump, hook up canister of solvent through a pressure regulator, appropreately set, to the port bewteen the pump and fuel rail (sort of like a tire stem, used to check fuel pressure, etc.). Run the engine on the solvent until it is gone... Re-engage the fuel pump and viola! Done. It can't be that easy, can it?

Now, I will probably have the transmission flush done at the shop, as I probably lack the tools, although I did see a method of flushing by emptying and filling with new transmission fluid a few times until things get a little cleaner. I gotta think that a professional job is better... Right? Also, and I am sure this is bugus, but when I had the vehicle inspected the inspector said the transmission fluid looked OK, but was starting to get a little dirty. But he also said, that some advise against a transmission flush beyond 100K miles. Is that true? false? debatable? wives tale?

I look forward to putting many, many more miles on my QX4. I am happy to have found this place... I guess it really is true, you can find anything on the internet these days. Thanks for any help you can provide.

[driverdriver]

Get a full transmission fluid change. Go to a place that has a transmission fluid exchanger. That tool will change all your fluid and not what is available in your pan (the traditional way of doing it).

I'm not sure whether the QX4 has got a transmission filter that also needs changing.

[Q451990]

The induction flush appears to be more than a quart of STP or other additive in the tank. I saw a show on DIY where they did a flush and it appeard pretty simple with the right stuff (although it was on a Tarus). Basically disable the fuel pump, hook up canister of solvent through a pressure regulator, appropreately set, to the port bewteen the pump and fuel rail (sort of like a tire stem, used to check fuel pressure, etc.). Run the engine on the solvent until it is gone... Re-engage the fuel pump and viola! Done. It can't be that easy, can it?

That really is all there is to it. On the Q45 - and I assume the Qx4 is the same... It's advisable to loop the fuel line to the return line, and then plug the return output on the fuel rail while doing the flush. If you just pull the pump fuse and leave the return line intact, some of the cleaner will bypass the injectors and return to the gas tank - possibly taking dirt with it. You want all of the cleaner going through the injectors and burning. The next question is where to buy the flush kit. I checked with my local BG distrbutor and could buy one for less than $300 - so assuming you already have an air compressor, it would pay for itself quickly.

As far as the ATF flush... the best way is with the machine. There are shortcuts, like multiple pan drains - but nothing beats a total exchange. I have heard the "don't flush after XXXX miles" advice too. I'd say 90% of the time, you're better off flushing. In the other cases (e.g my wife's 93 Tracer with 180K on the OEM transmission and probably fluid) the cleaning might dislodge too much stuff and it's probably better to just let it die of natural causes. In your case, I would try to find someone to do a flush - then an immediate pan drop/filter replacement - followed by another fluid exchange (but no chemical flush on the second round). That should eliminate any concerns about clogging the filter after the first flush.

It sounds like you're well on the way to having a very well maintained QX4 - Welcome to NICO!

Heath

P.S. - Denver is a beautiful city... I used to visit my Grandmother there every summer. Talk about different than the humid south! I thoroughly enjoyed watching the Broncos slam KC on Monday night... never heard the mile high crowd say "in-com-plete" that much in one game!