VStar650CL wrote: ↑

Tue Aug 01, 2023 5:06 pm

Then Hayden must be using something in there besides a traditional H-Valve design, but if that's the case, I stand corrected. I'll have to check that out. I wouldn't sweat the bubbles if they're diminishing, just if you still have them after driving awhile. It may be that your cooler is connected with pressure on the top, that makes it harder for the pump to flush out trapped air because it's fighting the buoyancy of the bubbles. That's the main reason for all that bottom-up designing Nissan does.

Here's what I found on the Hayden website. Seems to work as designed:
https://www.haydenauto.com/en/products/ ... ss-coolers

Very cool. I'll have to read their patent, I bet it explains exactly how they're making it bi-directional.

Oh, this is sooooooooo effing clever. They've added a special entry tube to a standard thermostat design that uses a reed valve to open flow on whichever side has pressure and close it off on the opposite side, so it acts like the fluid equivalent of a full wave bridge in electronics. Whichever side the pressure enters from is automatically diverted to the "plus" exit of the bridge (the thermostat) and the other side automatically becomes the minus (return). So the actual fluid flow through the coils is always in the same direction regardless of which side the pump is on.

"Elegance" in engineering is accomplishing the most beneficial results with the least parts. On that scale, this thing is pure genius! I'm so impressed!

I'm going to take the cooler I removed from the Rogue and install it on our 2017 Quest since it doesn't have the bypass valve (the Quest runs pretty hot). I intend to cut the fluid return line from the radiator and route it through a cooler mounted to the front of the AC condenser, then back to the beehive return. Can you help me with 2 questions per the diagram below?
1. Which hose is the return line - 21631 or 21631+B?
2. Which side is the primary fan?
Sorry to extend this Vstar and I am grateful for your help.

Admin - Please move this to the Quest forum if needed...

The B hose is pressure. Like I said, all the side-tank units are easily identified, the hose to the bottom of the exchanger is always pressure, top is always return. The fans run in tandem, there's no primary and secondary. Very few OE's use split fan setups except when an electric is an auxiliary to a mechanical, like the R51 Pathies. The reason is parasitic airflow. If only one fan runs then a lot of the air simply deflects off the front of the engine and goes back out through the other fan, to be sucked back in again through the grille in a vicious circle. Your fans should run together, both at the same speeds.