Postby smj999smj » Sun Sep 20, 2020 10:15 pm
The Denso plug will probably work fine, but Nissan has used NGK spark plugs in 99% of their engines and I've used NGK plugs in, literally, everything I own, including generators, lawn mowers and chainsaws. They are a terrific plug and NGK is the world's largest manufacturer of spark plugs. There are several plugs in the NGK line-up that will run just fine in the VQ40DE and the VK56DE engines. Any of the NGK "Laser" spark plugs were made for OE applications. The Laser Iridium 93759 is the actual plug that came from the factory in your engine and while the service interval recommendation if 105,000 miles, you can actually get 130,000 miles out of them. A lesser cost option that will give you 105,000 miles is the Laser Platinum 6240, which was the OE plug in 2005-2006. The Iridium IX is even less costly, but should be changed out around 60-70,000 miles. The Ruthenium HX 96355 came out about three years ago and I am currently running them in my 06 Pathfinder (I run the 6240's in my 08 Pathy). NGK claims they have better ignitability and are more durable than their other lines of plugs and you should have no problem getting 105,000 miles on them. They are also a few dollars per plug cheaper than the Laser Iridiums. As far as performance, I haven't noticed any difference between any of them. Power "feels" the same and gas mileage is the same, so it's really your choice as to which one to use.
PCV valves in Nissans usually don't fail unless the vehicle is badly under-maintained. That said, if I was going to go through the work to remove the PCV valve on a VQ40DE, I'm going to replace it with a new one. They are plastic and threaded and I would assume like most plastic engine parts, there comes a time where the heat makes them become brittle. It's not an expensive part.
I can't help you with the hose size to put on the bleeders. I have a vacuum brake bleeder kit so whatever size I have in the kit that fits is what I use. Make sure you follow the proper bleed order: right-rear, left-front, left-rear, right-front. Any DOT 3 or DOT 4 brake fluid will work fine, as will DOT 5.1, which is what I use. Do NOT use DOT 5!
The early years of the R51 with the V6 had problems with belt squeak or squeal. Nissan put out a TSB with instructions to check the P/S pump pulley alignment and adjust if needed and recommended replacing the tensioner with an updated belt, which was 1/2" shorter than the original belt. The slight decrease in length causes more tension to be put on it by the tensioner once it's installed. As a side note, tensioner springs do lose tension over time and should usually be replaced around 70-80,000 miles. That's why serpentine belt component kits are popular. If it were me, I would go to Rockauto and get Gates accessory belt drive kit # 90K38378B for $75. It has the shorter belt, a new tensioner, a new idler pulley and a lifetime warranty. If the belt wears out or a pulley starts squeaking, just order a new kit from Rockauto under warranty and send the old parts back (it'll cost you about $7 for their discounted shipping). Do it once and do it right.. Plus, Gates makes the OE parts on the North American R51's. If you do insist on replacing just the belt, then go with the Bando.
Coolant replacement is also due at 105,000 miles; your 2011 probably has Nissan blue, which is actually Pentosin Pentafrost A3 coolant which is sold at Rockauto and some parts stores (my local Autozone carries it). Valvoline Zerex blue coolant for Asian vehicles is a good alternative.
And don't forget about checking the wiper blades and cabin filters!