Towncivilian

I would advise against using any engine oil additives. Just let the oil do the cleaning. That can of harsh solvents has no place in a crankcase. The oil blenders spent millions in research and development and certification testing for many manufacturers' stringent standards as well as API certification; you can't outsmart them with an $8 "tune up in a can".

The door handles have a spring underneath that can break out of its place. My driver door handle's spring broke like a year ago and I've been lazy about replacing it. I can't find non broken door handles at junkyards. RockAuto has aftermarket handles, maybe I'll try one.

Shine a flashlight under the oil filler cap and try to see if there is any sludge or build up. Pull one of the IVTC sensors, make sure it doesn't look like this:

Fuel filters have no impact on starting or low RPM operation. If they are restricted, ability to attain higher RPMs will be impacted. If the fuel filter hasn't been replaced in several years, it's still wise to replace it.

My apologies - I was on my phone and admittedly only skimmed your post. Please use some paragraphs next time for easier readability. I second the suggestion to swap the two sensors (the guide I linked has pictures of their locations) and see if the problem moves (i.e. you get P1145 instead). If so, just replace the sensor and you should be good to go. Welcome to NPORA, by the way!

Check the actuator vacuum hose.

P1140 is not the MAF sensor. It's a camshaft position sensor code. Your dealership is incompetent. See this: www.jensbits.com/2008/08/30/pathfinder-ses-light-p1145-and-p1140/

Do use the air relief plug at the back of the engine at the center of the firewall. It is covered by a black rubber cap. What would be the best method to do a DIY flush? Drain, fill with distilled water, drive around a few days, repeat until it drains clear? How do you get the proper concentration of coolant if the system is 100% water?

The fuel filter on WD21s and D21s is in the engine bay next to the power steering fluid reservoir. Be sure to release fuel pressure before replacement by pulling the fuel pump fuse and starting the engine then waiting for it to stall. Put a drain pan underneath to catch gasoline.

Plugs, tune up, belts, rear shocks, fuel filter, oil pressure switch, brakes are easy to do yourself. Maybe even muffler replacement and a couple other items on the list. The rear drum brakes should last forever, just clean, lubricate, and adjust them yearly and you'll be good. Bring a flashlight and look under the oil filler cap, see if you can see any significant amount of sludge or crap build up. Check all the condition of all the other fluids too, if they are clean it's even more proof things were maintained well. Also bring a magnet and check body panels for Bondo - if there are any spots where a magnet doesn't stick, it is Bondo (but that isn't necessarily a bad thing, just nice to know). Look for rust in the strut housing areas - see the recall TSB for examples of what to look for.

I don't know, sorry. Hopefully someone else knows.

Ford Exploders and Rangers often have stacked plate coolers (Exploders have bigger ones probably). If you decide to use a junkyard cooler, flush it out very well with dedicated cooler cleaner as shown in the OP. It wouldn't hurt to flush out your stock cooler while you're at it too. Add a Magnefine on the cooler return line when it's financially convenient too.

No it's rated for 13K BTU which is 19k GVW.

I think on a WD21 a B&M 70268 is best due to its thin profile and stacked plate design. I'm sure Tungsten will agree here. I think AAP should have it, so you can get it cheap if ordered online with discount codes.

Glad to hear you've finally got the leak fixed. Looks pretty clean under the valve cover, looks like there's a decent amount of varnish but it's harmless. If you'd like to try to clean some of it out, use a synthetic oil marketed for its cleaning ability such as Pennzoil Platinum or Pennzoil Ultra. Don't use any engine oil additives ever. You can extend oil change intervals to 6-7k if you'd like with synthetic oil.

Mileage isn't everything. I'd be more concerned about whether oil & filter was changed at a regular interval rather than total mileage on the engine.

P0409 does not exist on your Pathfinder according to the factory service manual. I guess the EGR valve is something UK models have. I'm afraid I don't know what to suggest except to take it to the dealer perhaps; there's no circuit diagnosis in the service manual so it'd be difficult to diagnose yourself if it truly is an electrical problem.

Oh yeah, that stuff stinks. Almost as bad as gear oil I'd say. It's good fluid though, it's synthetic too.

Great, glad to head everything went well. Hope it stays that way!

68551-0W700

You shouldn't use anything on the pan gasket. You can stick some pan bolts through to help align the gasket on the pan before securing it. There is a significantly more expensive all metal version of the Magnefine that is reusable; you just replace the filter cartridge and clean the magnet. It's not worth the cost though in my opinion.

I believe the stock gasket on my R50 was rubber. You can buy the filter online, it's about $22 shipped. Search Magnefine on Google, it'll be the first link. You replace the entire filter every 30k; once unscrewed you shouldn't put it back together. It should be installed on the trans cooler return line.

I do not know if the OEM filter has any specific markings on it; mine was covered in a light coating of grey clutch wear material and I did not wipe any of it off to look. That magnet looks alright I guess. I don't remember what my in-pan donut magnet looked like. You may want to consider installing a Magnefine in-line filter which has an additional magnet that catches all ferrous wear material, and additional paper filtering media in the range of 35 microns to catch any other stuff (the in-pan strainer is more like a rock catcher in comparison). The pictures of the magnet don't show the other side which had quite a bit more grit than the visible side. I saved that donut magnet and will place it in the transmission pan next time I do a pan drop.

Coat the O-ring with petroleum jelly before putting it on the filter. I would install the filter then put the pan back up, making sure to secure the cooler line clamps first before the other pan bolts. Filter and pan bolts are 61 - 78 inch pounds, drain plug torque spec is 22 - 29 foot pounds. Use a new crush washer for the drain plug. Refill with the same quantity drained, turn engine on, select all gears then return to P, check trans fluid level. Use "COLD" range, check HOT same way later.

What brand/type of ATF did you use? What is the fluid condition currently? Does it smell burnt? Where is it seeping from specifically?