Advice on 2003 QX4 2WD

[tommyabward]

Just picked up a 2003 QX4 the other day with 83K on the odometer.

Everything I've read about this truck and its reliability is reassuring, but I'm concerned that everything, including fluids, is probably all original. I had a chance to look over some general info on the forum, but I wanted to get some more direct information. What steps should I take at this mileage to prevent any common problems in the near or distant future assuming, worst case, the previous owner (one owner) did nothing in terms of maintenance?

There's also a pending code, P1491 which I found out is for the vacuum cut bypass valve - does this most likely need to be replaced? If anyone can shed some light I would be incredibly appreciative!

Thanks in advance.

[yeldogt]

Are you in a warm dry part of the county? - shame it's a 2wd. The R50 (that's what they are called) was recalled for rust in the front rails in winter states with salt. Most of the 2wd cars got delivered to Fl and other warm states without a lot of off roading activity.

What did you get from the owner? any work orders/ paperwork -- did he take to to the dealer?

I picked-up a low mile 02 Path LE 4wd a few years ago from the original owner. Have had three. This vehicle had a mix of dealer/ independent repairs. Previous owner did have the coolant replaced at the dealer -- but, it was due when I purchased. When a older vehicle is purchased form an original owner with little done to it and no record of being changed -- changing out the fluids is prudent. The transmission just needs to be drained and refilled -- get the proper fluid (Nissan D-matic) and new drain plug metal gasket (so no dripping) from the dealer (or on-line dealer) I think it needs 4 quarts -- check the specifications (the manuals are available here). I would do the same for the coolant if you have no record and it looks to be the original fluid. Just drain and refill with coolant and distilled water 50/50 -- you can get a gallon of distilled water at the drug store for $2. The fluids from the dealer have the proper additive pac and will cost you maybe $20 more -- your doing a refresh. In my case the tires needed to be replaced and the rear brakes needed some attention -- so, I did the brake fluid flush at that time. Any quality brake fluid is OK - make sure it's a new bottle. Mobil 1 gear oil is a good choice for the rear differential - in the proper weight.

The rear brakes often require some attention -- all of mine have. They are drum .. and tend to rust/stick. Also, the cylinders and boots often need attention at this age. I would have someone look at them and fix if not working properly. I would only use OE parts and shoes -- a tad more money .. but less problems.The OE shoes are high quality. For front brakes I have had great luck with Zimmermann rotors and the OE pads.

I have a great independent who lets me get my own parts .. so getting good prices online is easy. The drain/fill plugs on the differential are known to be a problem - they stick. I could never have done this myself -- they had to heat the plug.

Good luck -- great vehicles .. don't try and reinvent the wheel or save $10 ... fix it once and it's done.

If you don't have a code reader .. get one. You only need a cheap/ simple one for $35.00. Reset the codes and see if they come back -- the valves on the emission systems are a known failure point .. simple and easy to replace if the problem.. sometimes it can be a wire.

[brando73]

Just curious. How much did you pay for your '03? I'm getting ready to put the wife's '04 LE Platinum edition up for sale this weekend. She went back to Germany to finish her Masters. Just don't want it sitting in the garage for two years and I don't need two vehicles. It's been an awesome vehicle.
I was thinking $4100. It has 138K miles, Toyo Open Country tires with less than 5K miles on them, new rear shocks, new brakes all around, and I recently did the valve covers and oil catch can. Needs absolutely nothing and everything is up-to-date. Think it's reasonable?

[yeldogt]

I sold my 02 LE in similar condition 140k -- for $4500.00 . Unfortunately, that was 5 years ago ... Edmunds is saying $3300 in clean or even outstanding condition today for your 03.

[AlanAZ]

In addition to all fluids, I would replace the fuel filter and run a couple bottles of Techroline fuel system cleaner, install a Magnefine filter in the AT return line, clean the MAF, & replace cabin filters.

[tommyabward]

Are you in a warm dry part of the county? - shame it's a 2wd. The R50 (that's what they are called) was recalled for rust in the front rails in winter states with salt. Most of the 2wd cars got delivered to Fl and other warm states without a lot of off roading activity.

What did you get from the owner? any work orders/ paperwork -- did he take to to the dealer?

I picked-up a low mile 02 Path LE 4wd a few years ago from the original owner. Have had three. This vehicle had a mix of dealer/ independent repairs. Previous owner did have the coolant replaced at the dealer -- but, it was due when I purchased. When a older vehicle is purchased form an original owner with little done to it and no record of being changed -- changing out the fluids is prudent. The transmission just needs to be drained and refilled -- get the proper fluid (Nissan D-matic) and new drain plug metal gasket (so no dripping) from the dealer (or on-line dealer) I think it needs 4 quarts -- check the specifications (the manuals are available here). I would do the same for the coolant if you have no record and it looks to be the original fluid. Just drain and refill with coolant and distilled water 50/50 -- you can get a gallon of distilled water at the drug store for $2. The fluids from the dealer have the proper additive pac and will cost you maybe $20 more -- your doing a refresh. In my case the tires needed to be replaced and the rear brakes needed some attention -- so, I did the brake fluid flush at that time. Any quality brake fluid is OK - make sure it's a new bottle. Mobil 1 gear oil is a good choice for the rear differential - in the proper weight.

The rear brakes often require some attention -- all of mine have. They are drum .. and tend to rust/stick. Also, the cylinders and boots often need attention at this age. I would have someone look at them and fix if not working properly. I would only use OE parts and shoes -- a tad more money .. but less problems.The OE shoes are high quality. For front brakes I have had great luck with Zimmermann rotors and the OE pads.

I have a great independent who lets me get my own parts .. so getting good prices online is easy. The drain/fill plugs on the differential are known to be a problem - they stick. I could never have done this myself -- they had to heat the plug.

Good luck -- great vehicles .. don't try and reinvent the wheel or save $10 ... fix it once and it's done.

If you don't have a code reader .. get one. You only need a cheap/ simple one for $35.00. Reset the codes and see if they come back -- the valves on the emission systems are a known failure point .. simple and easy to replace if the problem.. sometimes it can be a wire.

Thank you! This is really helpful. I live in Las Vegas, as does the previous owner, so warm and dry would be an understatement. Still good to know about the rust issues, planning on moving back east soon, so that'll probably become more of an issue then. I'm gonna go ahead and swap out all of the fluids this weekend and see where that takes me. Didn't really get any records or info, in that regard, from the previous owner. Took a risk because of the low mileage. All new brakes in the front, tires were balanced and have about 60% tread left. The drums in the back look like they haven't been touched, so I'll look into that.

Only thing that worries me slightly is swapping out the transmission fluid. I've read different things that honestly confused me-- people say don't touch it because it'll just cause problems, others say change it every 30K. What's the correct answer? Am I just paranoid at this point? I can't imagine a simple drain and fill causing issues, but obviously the last thing I want to do is deal with trans issues.

Thanks again.

[tommyabward]

Just curious. How much did you pay for your '03? I'm getting ready to put the wife's '04 LE Platinum edition up for sale this weekend. She went back to Germany to finish her Masters. Just don't want it sitting in the garage for two years and I don't need two vehicles. It's been an awesome vehicle.
I was thinking $4100. It has 138K miles, Toyo Open Country tires with less than 5K miles on them, new rear shocks, new brakes all around, and I recently did the valve covers and oil catch can. Needs absolutely nothing and everything is up-to-date. Think it's reasonable?

I just paid $6500 for the 03 - seemed high in retrospect but the low mileage was a big deal for me.

[yeldogt]

Between my company and business I have about 15 cars at any one time -- this has been the case for over 25 years ... 100's of cars.. millions of miles. Keep it simple ... people spend more time trying to find cheap alternatives to what is really very easy stuff. Cars with drain plugs on the transmission -- there for a reason. Most transmissions don't have a true filter -- it's a screen inside what is called a filter and rarely needs to be replaced. A simple dump of the filter in the pan will get out enough fluid to allow you to refresh with new. Same with the coolant -- dumping the radiator -- will get the stuff at the bottom of the system and refresh the coolant - it's the additives against rusting and corrosion that are important. I only go to the next step -- flushing the system, or dropping the pan if needed ... Frankly I can't remember the last time. If the fluids look dirty you can always do another refresh in 10-15k. Most people can't tell clean from dirty -- transmission fluid always looks a little dirty.

The first step is doing the simple refresh and see what you have. I can't stress this enough -- just get the correct fluids. Order them on Amazon ..whatever. You can't screw anything up if your putting back in what the factory put in when the vehicle was made. Don't listen to people who say -- it't all the same. I would not put a after market filter on the transmission line as mentioned above. Replacing the cabin filter is a very good idea as is the engine filter -- brand not important with this. Leave the MAF alone -- do no harm!.

Have the rear brakes looked over -- it's not unusual for them to stick/ rust and not be doing much. and the cylinders leak. Be mindful of what I said above about the differential.

Both of my 02's bought used had aftermarket belts -- and both squeaked. Get the OE belts if you ever have to replace -- they cost no more online and are high quality. Same for the wiper blades -- if the car still has it original wiper blade/frames -- Nissan sells the inserts (made by Denso) -- very high quality. Never replace a wiper blade on a Nissan or Toyota -- the blade frame is not generic .. it's designed to have the insert replaced. Cheap and long lasting.

The other very common item on theses -- The HVAC fan will stop blowing or stick on high -- its the module near the cabin filter. Just get the OE on line -- about $100. Fixed in 20 min.

[barnaclebob]

There's also a pending code, P1491 which I found out is for the vacuum cut bypass valve - does this most likely need to be replaced? If anyone can shed some light I would be incredibly appreciative!

Thanks in advance.

I had a P1491 code and replaced the vacuum cut bypass valve solenoid which is located in the rear of the car on the drivers side, somewhere around the spare tire or suspension maybe. I think if you ignore it, it could send extra fuel or fumes into the fuel tank charcoal canister and could ruin that which is a more expensive repair.

Its a fairly easy job that was made slightly more complicated for me because the solenoid i got in the mail was a mirror of the one on the car and the wire harness wouldnt reach so i had to flip it around and get creative with zip ties. I think the bypass valve and the solenoid are usually sold together and you can find them used, they are a common part on many cars. This is what you are looking for and they appear to go for about $70 ebay:

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/ ... 880000500F

The hardest part is getting the vacuum hoses unstuck but you can buy a special tool for that or use some hose p0ker things. Talk to the guys at the autoparts store if you are having trouble unsticking the hoses. You can also come back here for advice issues too. You may also have the bolts shear off but there is plenty to zip tie the bracket too if that happens.

Another possibility for this code is that one of the vacuum lines is plugged up but I haven't had to troubleshoot that. If you do some googling you can find some diagnostics on the cut bypass valve to determine if its faulty.

Just do a drain and fill on the transmission and I wouldn't touch anything besides brakes and fluids unless you get a code. Be ready for O2 sensor and MAF codes too, those are common but pretty easy to fix..

[yeldogt]

The car has a couple valves -- Nissan is famous for them failing when 10+ years old. I just got a P0447 -- that's the vent control valve. It's also an "open circuit" -- that can be the coil on the valve being fried or one of the wires -- the valves live in a nasty world back behind the rear tire. I will give a look when the weather gets better and replace if necessary.