peejay

This is gonna make me download every Nissan FSM, isn't it? Thank you for your explanation, as always. The warm liquid rises thing (ya made me google it)..."convection", I think that's part of the physics puzzle! Thanks for the suggestion on the 300ZX cutaway, it makes it a little better to visualize, but they really need a better team working on those flowcharts! Maybe they don't know how the system works, just that it does! (It still makes it look like (to me) that the outlet is acting as some sort of diverter, but I'll let it go...for now!) If I get bored enough, I'll rig up some wiring adapter between the Coolant Temperate Sensor and the harness, to try and monitor real-time the voltage change engine running, or resistance as the system cools, engine off.

Okay, question simplified (courtesy of AI) How does the temperature signal change (shortly after warmup) if warmer/hotter coolant only "touches" the coolant temperature sensor (via the Water outlet housing) once the thermostat opens? By my flawed logic, the system would run rich until the thermostat opens.

Alright, @Slartibartfast, just a few more pieces to the puzzle that I'm missing... (I'm trying to figure out how the Coolant Temperate Sensor responds to the coolant gradually warming up...) When coolant leaves the Intake manifold and reaches the Thermostat housing (and the closed Thermostat), how does the gradually warmer coolant reach the coolant temperature sensor/water outlet, or does it ONLY reach the outlet/CTS once the thermostat is open? But if so, wouldn't the CTS only read "cold" and "VERY HOT" coolant temperatures? And I may be confusing myself a bit here, this circuit is from a '02 Frontier FSM (I'm assuming the VG30/33 cooling systems are identical?), and it makes it look like coolant leaves the Intake manifold, gets to the Water outlet housing, then [if thermostat is closed] goes to By-pass hose, reaches Thermostat housing, and recirculates: (Also, the above circuit makes it look like (to me), that if the Heater is on/selected, coolant will not go to the Water outlet housing, but that can't be right, right?) I added lines which I thought represent the above circuit: Based on that, why wouldn't coolant leave the Water outlet housing as well as the bypass hose, even when the thermostat is closed? *** Last point (and this is WAAAAAY out there, but)... Is it possible, that coolant is "constantly" flowing out of the Water outlet housing and into the radiator, but because the bottom hose is closed off at the (cold) Thermostat, the coolant flow "stops", or better yet "backs up" and seeking the path of least resistance, is diverted into the Bypass hose? I'm sure that is not what happens, but why? Thank you for your time!

Thanks as always, Slart! I kinda see it now, I didn't know it was metered air coming in, and your explanation of it bypassing the THROTTLE seals it. (Also, I've tabled the wiring thing...for now...exploring other worm holes!)

HI, there! The way I understand it, when the engine is cold, this valve is OPEN, to allow air to bypass the intake, and thus give a richer mixture? And when the engine (and the heater in the regulator) warm up, the shutter in the regulator closes, and now air is no longer bypassing the intake, but is instead going INTO the intake, to give a less rich mixture? But that doesn't seem right, because the way the regulator looks to be plumbed, it seems that when it's open, it allows air into the intake? Help me see things clearly, please!

Anyone know where the "Main Harness Adapter Connectors" are, particularly 342M? Are they behind the fuse box? I've lost continuity between the fuel pump fuse terminal and the fuel pump relay input terminals, and need to track that circuit down. (Edit: For the time being, I'm dumb, I was testing the wrong terminals on the fuel pump relay socket!) Thanks! Or...are those adapter connectors gonna be one of those, or in this area? (Sorry, I keep finding "new stuff")... Or is THIS it, and the connectors are over on the RH side, behind the dash?

Your explanation makes perfect sense, my apologies to the engineers! However, had they gone "conventional" they may've been able to avoid that %#%#*@!! bypass hose, so for that, there is no forgiveness!

Thanks, Slart! And thanks for the REAL diagram, you've been telling us for years to get the earlier FSM's as well, now I see why! They must've omitted the drawing from later ones to hide their illustrious "design" of the cooling system. (Tstat being on the "cold" side is well-stated!)

Clear up this confusion for me, please! On these VG engines, when the thermostat opens, does hot coolant exit the engine via the lower radiator hose? And cooled coolant exits the radiator via the upper radiator hose?

The "easy" way would be use the VG33ER block, heads and accessories, and use the VG30 intake/fuel delivery, that way you won't hafta do any ECU swaps. Keep the VG30 heads for down the road (supposedly they have better cam profiles?) and keep the supercharger and intake stuff for later. The main catch is, the a/c compressor for the VG33 has different plumbing and won't match with your WD21 tubing so you would have to have them cut and brazed/tig welded to the VG33 tubing.

Thanks, all! Happy Holidays! (Edit) As usual, you all were right! Maybe if I'd've serviced this thing years ago, the cover/spacer wouldn't've been seized on there, and would've just fallen off, like the new one did! (This pic might show the spacer/bushing thingy better):

Oh? Pics? Does rebuilding require a press? Here's a pic of the backs of pulleys, OEM one on the left, incorrect aftermarket one on zee right:

Whoops, busted, forgot which forum I was in! It's a WD21 with a VG33. (I went ahead and ordered it from Nissan parts deal, couldn't find it (reliably) elsewhere.)

Is there an aftermarket source for thi or does it hafta be Genuine Nissan? I ordered a Gates one, but it's too loose/looks like a different design.

Wait, wait, wait, you can't just toss that in nonchalantly and expect us not to ask for a write-up!!!

Will do, thanks! (Thanks for the tip about how the dust cap is attached, I will not be opening that can of worms!)

Thanks, hawairish! So to remove the caliper (well, I actually need to remove the rotor) do you recommend removing the dust cap (and ifo so, does it pop/pry off?) and getting to the bolt underneath, or is it better to remove the two large bolts that secure the caliper to the backing plate? Or just remove the one (exposed) bolt, and the caliper should be able to be pulled off, no need to mess with that dust cap at all? (Also, I've been following/studying your writeup on the R50/D22 disc swap, thanks! That's what's led me to reviving this old post!)

Just stumbling upon this myself. I'm guessing the caliper can pivot on that pin, but the pivot pin cannot be removed? The floating caliper, and the caliper mount, are one assembly, and to remove the caliper, you have to remove the mount, by those 2 large bolts (17mm socket) @in2challenges mentioned?

Okay @Slartibartfast, managed to get what I needed (minus the hood insulation, forgot all about it!), everything you said held true! Now, because I'm not the sharpest spoon in the haystack, I didn't know that the parking brake cables separated in the middle. So me and my bro did it the HARD way, of removing suspension components to give enough clearance to slide the axles through the frame...yeah, don't ask... Of course we ended up mangling one of the dust shields in the process, but that's nothing a MAPP torch and some careful hammering, dollying, plyer-ing, can't get back close to shape, right?

Thanks, slart! Just the insight I needed! I'll report back how it went (if it's still there). (On the rear end, I've pulled one from a boneyard before and it was no joy, and that was in me younger days, so trying to get away with axles only if I can...last time was because I needed the LSD and the discs, this time it's just for a (potential) D22 disc conversion). (Oh, and they do still make the hood insulation (hopefully asbestos-free!) clips, so destroying the factory ones may not be such a bad take.) Edit: The insulation clips don't spin off (misleading design!), probably hafta use some sort of panel removal tool.

Found a decent parts WD21 this past weekend at the junkyard, but there was intermittent rain and I was too lazy to pull the parts I wanted, so I'll be going back. Could use some tips on the easiest/best ways to remove the following: - hood insulation panel (do the retaining "clips" just unscrew? Could test it on mine, I guess) - rear disc brakes (once I get the calipers off, just remove the 4 nuts from the inside of the axle housing and the axles should just pull out? Will I need a slide hammer? (Gonna try and get the parking brake cables and hard lines while I'm at it) - spare tire carrier (not looking forward to this, I really just need the main swing out portion (mine got bent from being rear-ended), but will I hafta remove EVERYTHING, including mounting brackets behind the interior trim?) Thanks!

Lol, I thought for sure you were about to say "stepped my foot on my [sheet metal brake]. Way to be resourceful, gives hope to us all, thanks!

Don't quote me on this, but according to this site, the gear ratios (and nearly everything else) should be the same: https://hgmelectronics.com/blogs/hgmelectronics/re4r01a-and-re4r03a-transmission-control-and-the-compushift-sport

Mighty fine job, level9! What kind of undercoating did you use and how did you make such nice bends in the aluminum?

(Is a faulty timer the cause of closing (slamming) the doors sometimes causes the door locks to lock on their own?)