Plumbing makes no sense? Coolant / plumbing experts weigh in?

Joined
11 January 2021
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961
Location
SW Ontario, Canada
I know there has been some discussion on the cooling system recently, but I just noticed something very odd while changing the coolant hoses in my '01 NSX. 19522-PR7-J02 "Hose A bypass" exits (the block?) winds around in front of the thermostat, goes up and through some piping that's welded to a crankcase breather and then runs back down, practically crossing over itself and connects near the thermostat via 19524-PR7-A01 "Hose C bypass". It looks very strange - why not skip the runaround (and an additional coolant hose) and just connect directly since there are no other connections in between? Heating or cooling the crankcase breather?
PXL_20250315_172917351-min mod.jpg

In the pic, "Hose A bypass" is on the right and goes under "Hose C bypass" as it comes back around. I'm tempted just to plug "Hose A bypass" into the block where "Hose C bypass" plugged in and skip the extra plumbing and Hose C bypass. Will my cooling improve with the lowered resistance? Could I have saved the $10 for "Hose C bypass"?

Who am I kidding? I'm too chicken to not plumb it as Shigeru intended. But I'd love to learn what is going on here.

Bonus question: I got a nice set of tools for accessing those hose clamps from odd angles, but how do I get to the clamp on 19506-PR7-A01 "Hose, RR WATER". The clamp "grabbers" are on the bottom. I can see why, to avoid impinging on 19506-PR7-A01"Hose, RR WATER" beside it and 79728-SL0-A00 "Hose Water Inlet (engine) above it. But how do I get to it with that {air injector?} line running right in front/under it?
PXL_20250315_193557577-min.jpg
 
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I am not going to wade into the piping mystery associated with the stuff around the NA2 throttle body. Even with my little coolant system map and part number list it was hard enough trying to keep track of the 'new hoses go where/' around the throttle body let alone venture into the 'I can do better world'.

With respect to accessing the release tangs on the hose clamp, what kind of tool are you using? I used one of these for most of my hose removal. I tried the cable style removal tools; but, had little success with them. Perhaps because I got a set that was too flimsy.

I also have two rather large heavy needle nose pliers, one with a long straight and one with a long bent nose. I might have used the bent nose plier to squeeze the tangs and rotate the clamp up and then use the locking pliers to hold the clamp open; however, I am thinking that on this one, after the hose was removed from the firewall side I went Rambo and cut the hose off the spigot. With the hose out of the way this gave access to the clamp tangs to allow removal of the remaining portion of hose on the spigot. When the hose went back on I think I positioned the release tangs slightly differently - more to the left side of the engine. However, this could be false memory.

Have you done the heater hose yet - the long one that snakes up behind the EPS rack to the heater valve? I left that one for a future day because I could not even see the release tangs on the clamp at the bottom end. I also had the same problem with the short hose on the oil cooler. I could see the release tangs on the clamp on the far end up could not access them. I did this in late October and it was getting cold with a risk of snow and I was afraid of running out of time before I had to drive the car to the storage compound for the winter.
 
Just happen to be replacing a whole bunch hoses on my RDX thus my "hose replace kit" was there for the capture. I've used every one of these tools in the last few weeks. Longer yet handles like the Lisle above would be nice. 20250316_171129.jpg
 
Answering my own bonus question: There is no way to get a tool on those tangs without removing the air line, which was only about 5 minutes once the main 2 hoses were removed. Should have done that right off the bat. I made a mistake when reassembling, putting the hose on and then trying to put the air line back on. Oops. Engine side, air line, firewall side.

For tools, I bought a hose clamp pliers set on amazon, which included one of the cable operated ones, & I'm sure glad I did. I used several of the pliers with different ends for the different clamps. They had small rotating clips that grabbed the tangs, allowing me to move axis of the pliers while the tangs were still clamped, and they lock holding the clamp, making them easier to move around. Not awesome quality, but good enough for this DIY turkey.

I've done the rad, the tunnel below, and the engine bay ones with the thermostat. I'll tackle the heater hoses & the oil cooler later this week & see how they go. I'll have to make a thread when I'm done.

Still hoping for a cooling expert to explain that labyrinth by the intake.
 
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