QuasarDecimari

Yep. As far as I can tell, it looked like a little thermistor. The pathfinder doesn’t even have a wire on the harness for that pin, so it won’t affect it at all.

Just did this myself about a month ago. The 5th pin on the maxima is for a little thermistor that the pathfinder doesn’t utilize, because the pathfinder has an auxiliary intake air temperature sensor. It snapped on easily, fit perfectly in the stock housing, and boy did it restore a good bit of power. No issues to date!

Depending on the year and engine on this, it might not be possible. I know my 2001.5 3.5L has unique sensors for each bank, so the same sensor can’t be used on the upstreams and downstreams, without changing the wiring. Mostly because wire lengths are different, and so are the connectors, but I don’t know about all pathfinder models being that way. I know it was a huge pain to source the correct O2 sensor for my Bank 2 Upstream sensor because there were like 8 different styles. It’ll be cheaper to change the O2 sensor, and easier, of course. Here’s the thing, the cats typically don’t degrade as fast as the sensors unless you’re having engine problems, like rich conditions or misfires. Its a lot more rare for the cats to go, but not unlikely. I would suggest changing the O2 sensor first, and running a bottle of Cataclean (or whatever it’s called. Just follow the bottle directions. The stuff works really well). Worst that can happen at that point is you have a new oxygen sensor, and that’s peace of mind if you have to change the cat. I’ve got almost 200,000 miles on my pathy, with stock cats. Still passes emissions like new, and that engine’s been through some rough times. IF you’re really wanting to crack down on it before spending the money, pull off the cat and shine a light through it. See how well you can see through it. If its breaking up, or very dirty, it might be worth changing. If it’s dirty, but not breaking up, it might be possible to save. Once it’s off, and looks to be in one piece, grab a bucket and about 1/4 a cup of laundry detergent, and fill up the bucket with water and the soap. Let it foam up, and soak the catalytic converter in it for 12+ hours. When you take it out, give it a good rinse, and allow it to dry. If you have any high-temp rust-protectant paint laying around, it doesn’t hurt to clean up the outside and give it a coat, but it’s not necessary. If it looks much cleaner inside, throw it on, bolt everything up, and see how it does. I also don’t recommend doing the lacquer thinner trick if you read up on that anywhere. It can cause some issues with the fuel pump on these vehicles. Good luck!

If the diameter of the seal is the same, and the threads are the same, you won’t do any harm. I’ve heard mixed opinions about using larger filters than the factory design, but most opinions have agreed that using a slightly larger filter can have positive effects. I know for older engines, it helps to have more oil in the filter to pull from when starting, and for some things like camshaft variable valve timing, I’ve heard larger filters prolong the life of that too. Regardless, compare the filter to another brand. If you’re at a parts retailer, ask to see another brand (like a Purolator), so that you can compare shapes and sizes.

Now THAT’s attention to detail

Even for a QX4, that price is way too high for a 2003. Could snag an R50 Pathfinder for $2000 or less for the most part. The fair market value is around $2000-$4,700, so $5000 is really kinda pushing it. https://www.kbb.com/infiniti/qx/2003/qx4-sport-utility-4d/?vehicleid=2569&intent=buy-used&category=suv&mileage=160535&pricetype=retail&condition=good Fantastic vehicle, of course, but at over 170,000 miles, I wouldn’t pay more for it than you would to rebuild or replace the transmission/engine... which is around $2000-$3000. Given that you might not know how well it’s been taken care of, and that the automatic transmissions in the R50 or QX4 can go bad fast if not taken care of, I’d keep that in mind with the price. Hopefully others chime in, don’t just take my opinion or $0.02... unless it’s reasonable enough to you. If he’s stern on the price, give him your best offer, and let him sit on that. If he gets no better offer, he might hand it over.

New Update: So I let the pathy sit for a few days while I waited for my sensors to arrive. When the weather was nice and warm, I threw on the 2 camshaft variable timing sensors, and a new crank position sensor (rear one to the flexplate). Fired it up and it started instantly, no problems, not a shake or rumble, and it didn’t seem to have as rich of a fuel smell from the exhaust. I have yet to change the oxygen sensor, but I anticipate doing so this week. I let it cool down for several hours, then started it again for a test drive. No problems starting, no misfire. Started it today to drive to work, no misfire. Parked it at work for a few hours, then went to start it and go to lunch... misfired all over the place again. What the heck. When I started it to go home from work, it didn’t misfire at startup then either... I’ve started to see a trend. Every drive I have done, it makes it to operating temperatures for a good amount of time, but it seems when I drive it for shorter trips, then start it the next day or hours later, it has no problem. My drive to work is about 14 miles, and takes about 21 minutes, driving at high RPMs on the highways. I tend to see the rough starting condition after driving to work or home from work. I’m really getting baffled by this. I’m losing no coolant, the oil looks fine, coolant looks fine, no overheating, no performance loss, no strange MPG, no check engine light, new plugs, new coils, new injectors, new fuel filter, new timing sensors, passed emissions, and so on... but the issue remains.

This is really good to know! I’ll have to pull down the sensor and take a look at it. I remember it bring covered in fine metal shavings the first time I removed it a while ago.

So, this continues to get more interesting and frustrating as time goes on. I’ve verified that I don’t have a head gasket problem (whew), but even with the past several starts with misfires, my engine refuses to throw and codes. For some, that’d be a good thing I guess, but to me, especially when I know something is wrong but the computer doesn’t, it bugs me. So I called in a professional. A super friendly mechanic from a group I’m in (NORAC) decided to swing by and have a look. He hooked up his diagnostics computer and started probing around. Hiding in the computer were two codes, P1110 and P1135, which are the timing codes for bank 1 and bank 2. They’re both out of range, and as he made an attempt to override the CVVTS and advance/retard timing, nothing happened. Interesting, the timing won’t change at all, even at high RPMs or warmed up, and even more alarming, he sees these codes but my check engine light remains off, and my OBD2 reader says all is well. So there’s a timing issue. The computer is basically guessing at startup, causing some issues temporarily. Plus, the Long-Term Fuel Trim was at 94%... which means it’s DUMPING fuel, consistently, to run... explains the really rich exhaust smell. Oh and on top of that, I’ve got a really lazy Upstream Oxygen sensor in Bank 2. Which again, the check engine light has said nothing about. He proceeded to disable cylinder 4’s injector, to make it misfire, which made the engine hum a little and upset it, but nothing compared to how it misfires when starting (which shakes the whole engine). His explanation on that is that it certainly isn’t just cylinder 4 misfiring at startup, but the computer is only noticing cylinder 4. So with all this in mind, I have a bit of probing to do electronically. I’ve got a new oxygen sensor coming in tomorrow, and I decided to buy the two camshaft variable timing sensors as well just because they’re not too expensive and easy to replace. This has turned into something a bit more alarming, though. I’m happy to not have to worry about a head gasket issue, but it’ll be unfortunate if the computer is going out, or something of the sort. It’s just confusing that no codes are popping up at all... ESPECIALLY considering that she just passed emissions too, with no problems or weird numbers. So there’s my update dump. Anyone else wanna hop on this adventure?

Sounds like a plan. In the recent coolant flush (a bit of a mishap with the freezing temps in Colorado...), I never observed any small bubbles while running. One thing I hate about these engines and cooling system stuff is I have never had luck with running the engine without the radiator cap. It overflows as it warms up very quickly, and even with a very large funnel, it’ll erupt once it hits operating temps. Dunno if that’s normal, but its a PITA.

Unfortunately, I have bad news. The issue isn’t gone completely, just seems less drastic. I’m running out of ideas, and slowly getting cornered in the dreaded “Blown Head Gasket” realm. New spark plugs, new coils, new Injector, PCV system fixed, new fuel filter, new MAF. Just yesterday, I added about half a quart or coolant to the radiator, even though there was plenty in the reservoir. Under the oil cap looks fine, and pulling the dipstick, the oil is nice and clean, no milky substance signs still. Regardless, that doesn’t mean I’m in the clear. I’m starting to think that the cooling jacket is leaking into cylinder 4 from the head gasket, so when the engine is shut off, the residual pressure in the system depressurizes through the cylinder and the small amount of coolant sits in there until it doesn’t have the force to push any more in. Then, by starting the engine, it has issues in that cylinder until it’s burned off. The 127 PSI of compression in that cylinder trumps the 13 PSI cooling system, making it run perfectly while the engine is in motion... Does this sound pretty feasible? I’m running out of ideas as to anything else it could be. I’d hate to have to tear it down again after just changing the head gaskets 16,000 miles ago

Welcome to the party! That’s what I ended up doing when I “discovered” the valve. I fastened it to where the valve was always loaded for more rear braking. I’m waiting for the midwestern Colorado weather to allow for me to toy around with this a bit, sheets of ice and snow aren’t exactly ideal for brake checks!

Amazes me that people are allowed to drive their car without knowing at least the basic differences between the caps under the hood...

Match a SFD with the lift size for the R50 and CV angles aren’t an issue. Anything over 2” without a SFD is going to cause some headache later on.

Perfect. And while Warm are definitely nice, my Mile Markers have been going strong for a few years now. I would’t worry. Oh, and I’d avoid Carquest axles. I used to work at an Advance Auto Parts and we sold Carquest axles. I swore by a lot of things there, but not those. I’ve broken more carquests than anything else, and I saw so many of them returned constantly.

Of course! Get some manual locking hubs when you get the chance too. You’ll see most everyone praising them in Pathfinder pages. They help gas mileage a little, and definitely keep those CV axles in good shape while you’re not needing 4WD, so they’re nice and tough when you actually need them.

Some perspective: My OEM CV axles lasted 150,000 miles. I only changed them because there was a tear in one boot, but otherwise they were still strong. My recent axles (remans, usually) have lasted anywhere from 10,000-20,000 miles or less. I do, however, now have 33” tires, which puts a lot more stress on the little guys offroad, but still.

Of course! That’s what this community is here for. Hopefully it all goes well from here. Just check on it periodically, especially the dipstick, to see if anything changes. Depending on the engine model, Nissan makes some pretty robust engine designs, I really wouldn’t worry. Glad I could help.

Definitely a key point, hence the reason it would be a desirable fix to lower the LSV, than to raise the spring mount. More work, definitely more work, but possibly more accurate. I’ll have to put some thought into that one

Oh trust me, I remember! When I tore my engine down recently to rebuild it and freshen it up, the alternator was the biggest pain to reinstall when putting all the pulleys and accessories back on. You’d think for an item that undergoes the stress that it does, it would be a little easier to get to. I also despise whoever’s idea it was to make the rear nut of the thing removable. I always lost it right as everything would get into place. Ended up using superglue to hold it in place temporarily while I got everything put together. But yeah, if certainly sucks to do, but getting it off and testing it off of the vehicle is going to give you a better place to hit the ground running.

Just as another bit of supporting evidence, Here’s some pictures from when I rebuilt my engine. The first picture is when I was taking it apart to clean it and replace the timing, the second is after. Look at the timing stuff and rear timing cover and you’ll notice loads of the dark brown dust/gunk. It was just oil residue that had been burned onto the aluminum over time. The engine was otherwise perfectly healthy. It’s a normal thing as engines get older, and this VQ was at 186,000 miles when I did this teardown. Now its bordering 200,000.

Don’t be alarmed, I did the same thing recently after rebuilding my engine and having a misfire issue. I pulled off the oil cap, and there was some sort of residue there, and I freaked out, assuming the worst. In this case, what you’re seeing looks normal, at least from what I’ve seen. However, lets not just shrug it off immediately. What you’re likely seeing is the results of colder outside temperatures (assuming its winter where you are currently), short driving trips, or potentially a clogged PCV system (unlikely, but possible). You see, when your engine warms up, it dumps a lot of fuel to help it warm up faster and get the catalytic converters warmed up so emissions and oxygen sensors play nice. A warm engine is more efficient, and your crankshaft bearings take less of a beating at higher temperatures. While everything’s expanding due to heat, and oil is being whisked around, that excess fuel dumped into the cylinder can blow by the piston rings a little under idle/warming conditions. This is called blowby. The result is a small amount of gasoline mixing in with your oil. Conveniently, modern engines have a preventative measure for any damage that would cause, called the PCV (positive crankcase ventilation) valve system, which allows the pressure from the blowby, and the evaporating gasses from the fuel, to be safely vented into the intake to be burned off. The oil cap, being at the top of the engine, and being made of plastic, is typically cooler than the rest of the engine. Residual gasses from the oil and fuel blowby can condense on the oil cap, leaving behind a range of strange debris or colors (sometimes yellow, tan, or dark brown). This is completely normal, and should only really raise a flag if there is a lot of it, your valve covers and other sealed surfaces seem to be seeping oil, or you have poor engine performance/idle (this would indicate a possible faulty PCV valve). This sort of thing tends to pop up the most during colder weather, and especially in winter climates, due to short trip driving or letting the engine idle up to temperature for too long. So now that you have an idea of what the issue COULD be, it’s a lot less alarming. I really wouldn’t worry, but lets check a couple things! First of all, you said you changed the oil. By dumping the oil or checking the dipstick, a very alarming and fast indication of a blown head gasket would be a milkshake-like oil substance. Usually, it looks a lot stranger than brown sludge, so cross that off your list. Do a quick google search on blown head gasket oil, and you’ll see what I mean. It doesn’t take much for the coolant and oil to mix to make the nasty stuff, and you’d definitely notice it if it were severe enough. You also mentioned checking the radiator. While it’s less likely for the oil to make its way into the cooling system with a head gasket issue, it’s still possible, of course. Typically, the exhaust gasses are what make their way into the coolant, and while it can be hard to detect, there are texting kits for about $40 at local auto parts stores that allow you to test and see if you have exhaust gasses in your cooling system. They’re pretty simple to use, but you might only want to for peace of mind if you’re still not convinced. If you want to put some time into diagnostics further, pull your spark plugs and look at the color of the ceramic tips around the electrode. There are plenty of images online that can tell you how to “read” your spark plugs to know if you’re burning oil, running rich, lean, or have a head gasket problem. If it’s a small leak, it may not be noticeable. While you’re at it, rent a compression tester, check cylinder compression, and perform a leakdown test on the cylinders. This can be one of the fastest ways to indicate a failure of some sort, whether it’s a compression issue, valve issue, or head gasket. You could also rent a cooling system pressure tester. If you have a borescope, this can be really useful, but not everyone has one. You can perform a leakdown test according to the factory PSI specs of the vehicle. Typically, if it holds the indicated pressure (typically 13 PSI for older pathfinders), for 5 minutes or more without dropping significantly, you’re fine. Take it with a grain of salt, because a rental kit may not be 100% accurate, and could leak down even if you don’t have a leak, but it’s usually very slow. Sometimes, if you’re lucky (and unlucky I guess), coolant will come out of the damaged part of the head gasket around the heads or block, indicating failure. With a borescope, in short, you could look in each cylinder after a leakdown test to see if there is any coolant puddled up on the piston. Finally, an old trick from one of my mechanic buddies: Get a white piece of printer paper. Take the dipstick and wipe it off, dip it again for fresh oil, and put a good drop of it on the paper. Try and keep it as collected as possible and not splattered all over it. Let it sit until it soaks into the paper all of the way. It could be a while. If there is any small residue from a head gasket failure, typically it’ll sit on top of the paper and not soak in. Otherwise, the oil should soak into the paper and have very little variances in color. Obviously this is no engineering test, but it’s another quick and easy one for peace of mind. With all of this in mind, “brown sludge,” as you called it, could potentially be a different issue, sludge buildup. This comes with a range of other symptoms, however, and can be found various ways. If the previous owner took good care of her and did routine oil changes, cross that off your list. Regardless, throwing in a little Seafoam into the oil a few hundred miles before your next oil change can’t hurt, and could break up any potential sludge you do have (I usually drain about a quart of oil, dump a bottle of seafoam in, and run it like that for a day, changing the oil the next day). Good luck! Let me know if you have any questions!

Though the shop did the repair, and I’m not entirely sure where you’re located, did you pull off the Alternator? If so, would you be keen on removing it again? Ideally, I would get that sucker off of there and borrow a ride to a local auto parts store. I used to work at an Advance Auto for a while, and we bench tested the alternators there. Doing that, you’d be able to isolate if it is the alternator that’s the issue, or something with the vehicle. Not exactly a simple job, but if you know what you’re doing to remove and reinstall it, testing the alternator on its own gives you a really good place to start troubleshooting.

Actually, I don’t think there would be much issue with this. I had it attached for the longest time with the 7” rear lift and the spring still seems to have retained its shape. Its a tough little sucker. This is what I was thinking of doing, ultimately. I can’t imagine it being too difficult to extend either, just a plate with a few bolt holes. Regardless, I’ll still see if I can conduct some stop-times and hard-braking angles beforehand. Sent from my iPhone using Tapatalk

So here’s a followup on the issue: This was a user-induced issue, as I modified the PCV system slightly when changing my intake for a snorkel setup. I put a small breather filter on the PCV breather inlet, instead of reconnecting it to the intake. By doing so, crankcase pressure and gasses caused oil to buildup in that filter until it was barely breathing and clogged. The engine only had one area it could vent crankcase pressure, which was the PCV. With the PCV constantly blasting pressure into the intake manifold, oil could be picked up at that velocity, spitting oil into the intake manifold. If you look at the lower plenum, before the manifold collector on the VQ, the PCV releases pressure and gasses through a tube right above the intake valves for cylinder 4 and 6. Noticing a small trickle of oil draining into cylinder 4, that would explain a lot. The oil would get into that cylinder and take a moment to burn off when starting the engine, causing the misfire. That would also explain why cylinder 4 was the only culprit. By fixing the PCV intake so that it is connected to the air intake, as originally designed by Nissan, all the small oil seepage around the engine has stopped, the intake doesn’t have oil in it, and it seems happier altogether. The misfire still persisted after doing this fix, until I changed the spark plug for cylinder 4, which would make sense if it was burning the oil off in that cylinder. Lesson learned? The PCV system is important and designed the way it is for a reason. Don’t mess with it. If you suddenly have a misfire upon starting, and it points to cylinder 4, check your PCV intake for blockages, and replace the $2 PCV valve. For just a few hours and a couple dollars, it saves a bit of headache.