Installed my Aux. Trans Cooler

[PowerslavePA]

PICS:








I pulled the return line off he factory warmer, and used a coupler
to leave the factory trans line in tact:

Even though the factory return line elbows into the factory cooler,
it was very pliable and shaped well.

[PowerslavePA]

I could not edit my post so:

Oddly enough, when I pulled the hose off the factory cooler,
nothing poured out of the hose, or the cooler nozzle.
I got a drop or to, which made it that much easier, but I
did have a pan under the car just in case.

[VStar650CL]

Nice job, neatly done.

If the car has been sitting for a bit, you won't usually get a torrent of fluid coming out of the pressure-side hose. I usually pinch them off anyway, but there's often just a trickle. Not sure why, maybe the way the pump is constructed won't let the lines vent back to the case and it's holding fluid like coolant that won't drain till the radiator cap is removed.

[PowerslavePA]

The Aux cooler is installed on the transmission fluid return line from the lower rad.
The Aux cooler does not go in the engine coolant lines at the cooler/warmer.

[VStar650CL]

The return line is the top one on Nissan side-tank heat exchangers. The engineers claim having the pressure at the bottom and the return at the top makes air bubbles more likely to chase out (not that a healthy pump with sufficient fluid should make many bubbles). So if you're into the lower line from the beehive, it's the pressure line.

[PowerslavePA]

There are four lines at the cooler/warmer on the transmission.
There are two lines, TOP RIGHT and BOTTOM LEFT, the coolant lines, and they
don't go anywhere near the radiator. They are also larger in diameter.

The smaller fittings, Top left, and BOTTOM right, are CVT Fluid lines.

Looking down into the engine bay:
Top left is the Trans Fluid OUT to Radiator.
Bottom right is the return FROM the Radiator.
Top Right is coolant line.
Bottom Left is coolant line.


Is that the wrong direction of flow?

Diagram seems to show that the bottom left is FROM the radiator, and the
top right is TO the radiator? Do I need to reverse the lines? Looks like it
from the diagram I saw.

[PowerslavePA]

Which side is TO rad, and which side is FROM rad?

[VStar650CL]

I think you have the inlet and outlet fluid lines reversed. Outlet is the bottom hose on the hive (driver's side of both the hive and radiator). It would be the bottom fitting on the radiator on a side-tank setup like the Altima. Return is the top hose on the hive (passenger side of both the hive and radiator). Like I said, they always want the fluid flowing uphill as much as possible. The coolant lines aren't really relevant, but the inlet is always the side with the thermostat on it (twacked, I know, but that's how Nissan does it).

[PowerslavePA]

I need this verified, before I take the hoses off the factory cooler,
and start the car and see which fitting fluid shoots out of...

I can put the lower right hose back on the fitting, but I will need
to cut a longer hose for the upper left, to cooler. Still have to
pull the grille off...

According to this diagram, fluid goes out the top, and returns
through the bottom:

[VStar650CL]

If that's right then it's backward from everything else in the Nissan line, but I won't say it couldn't be backward. The Rogue '10D is slightly different from the sedans. Or it could be a typo by the technical writers, that wouldn't be a first. Good to know either way.

[PowerslavePA]

If that diagram is right, then the cooler is hooked up correctly.

That is part of the cleaning instructions for the lower rad cooler when
you rebuild, overhaul, or replace the transmission. If you find shavings
that are 1mm or more thick, they want you to replace the radiator before
installing the new, rebuilt or overhauled trans.

[VStar650CL]

I know, I'm just wondering if maybe they mirrored the drawings (that wouldn't be a first) or if the Rogue '10D beehive really is backward from the other '10D's. If it is, good to know, because I never noticed it.

[VStar650CL]

Btw, unless the cooler has a bypass valve (it doesn't look like yours does), I personally don't think it makes much difference which side of the heat exchanger the cooler is mounted on. With a bypass you obviously want it sensing the beehive temperature, but with an open series loop it just means one does a little more work instead of the other. That shouldn't make any difference to the total BTU's the system can dump.

[PowerslavePA]

The side does matter, because it goes through the radiator
after the trans mounted cooler. So, it is heated by the
coolant lines at that cooler, then cooled to the temperature
of the coolant in the radiator after exiting the trans mounted
cooler.

If I put the cooler on the wrong side, it will cool, then go into
the rad, and then temp match the coolant there. I won't get the
5-10 degree drop in temperature after the rad.

That is why it needs to be on the RETURN line from the rad,
after that stage of cooling, then the 2ndary stage through
the AUX cooler, then back to the trans mounted cooler/warmer.

[VStar650CL]

If you're not exceeding the soak capability on either side, then you're simply shuffling the heat around. The total BTU's being soaked off the fluid will be identical.

[VStar650CL]

For those interested, this is why the FSM specifies back-flushing the cooler and not forward. This is a dissection of a typical Nissan heat exchanger element (air-cutter used, so before anyone sounds off, I know it isn't very neat):

You can see in the last pic how fine the cross passages are, smaller than a millimeter. Nothing larger than that will pass through, so if you're evaluating debris as suggested in the FSM, you won't ever find anything on the return side. Whatever debris enters from the lines will always be trapped at the inlet.

[PowerslavePA]

Seeing that? I may bypass it with one of these:

That will eliminate the radiator exchanger. Can mount it on the
K-frame cross-member, just below the rad...

[VStar650CL]

That will do it, but if you're in western/northern Pennsylvania you may need to worry about over-cooling in the winter months. That isn't healthy either, I'm sure you know how much cold lubricants can accelerate wear. You might want to consider a shunt you can throw seasonally to bypass it in the cold weather.

[PowerslavePA]

My 2016 has a thermostat at the CVT mounted cooler/warmer.
No matter what, it will be ~180 degrees going through that bypass
one. It would behind the radiator, just below the built in cooler
on the K-Member.

The CVT fluid should between 175 and 225 degrees Fahrenheit. Temperature
can be lower than 175°F is still healthy, well-maintained, while temperatures
higher than 225°F can indicate a problem.

During acceleration or hill climbing, the internal temperature inside the torque
converter can quickly rise above 350°F.

Being around the 110-120F is not bad, instead it provides thicker MOFT mitigating
boundary lubrication and oil oxidation phenomena, and that's positive. You'll
have less gas releases with colder, but not too cold fluid. CVT is still flows well
down to 70 degrees, even 50. With the thermostat, I don't think it will get lower
than that, or even close to that.

However, I probably won't use that other cooler unless the one in the rad
breaks or clogs.

[VStar650CL]

Pretty much all the '10x versions have that thermostat, but particularly with the gen2 Rogues, in very cold weather many people here from Canada and the northern US have complained that the car artificially holds low gear ratios for a long time after startup as the transmission struggles to warm up. Not that it necessarily hurts anything, but the trans temp doesn't come up quickly even with the beehive when driving on a flat road in very low temperatures. So whether over-cooling is an issue depends a lot on how cold your local climate gets and how flat the terrain is. You're quite right about the TC temperatures, so if you're climbing hills right out of your driveway then it's probably a non-issue. Ditto if you live in say, Philly, where winter is cold but not usually sub-zero. Pittsburgh or Happy Valley might be a different story. That's a judgment call which only you can make based on your own circumstances.

[KoiMaxx]

Pretty much all the '10x versions have that thermostat, but particularly with the gen2 Rogues, in very cold weather many people here from Canada and the northern US have complained that the car artificially holds low gear ratios for a long time after startup as the transmission struggles to warm up.

I can attest to this as someone who regularly drives in -20C or colder weather around 3 months of the year.

[PowerslavePA]

Being in PGH, lots of hills. It is not very flat here. Though, I run to
Ohio three days a week, 400 miles per day. That is flat, and it is
colder there.

[Svtrit]

My 2019 runs around 2500 Rpm at 30 MPH below 20F for the first 2-3 miles. It’s very annoying, but part of CVT ownership, I guess! My 2016 did not do that.

[PowerslavePA]

That is also because TCC lockup is not available till the trans fluid
reaches about 140 degrees. You're ~200RPM higher until the TCC
locks up.

[phmichel]

The return line is the top one on Nissan side-tank heat exchangers. The engineers claim having the pressure at the bottom and the return at the top makes air bubbles more likely to chase out (not that a healthy pump with sufficient fluid should make many bubbles). So if you're into the lower line from the beehive, it's the pressure line.

Vstar - I just swapped the external CVT cooler on my 2013 from a Hayden 678 (non-bypass straight through) with a 699 (bypass "valve" activates about 165dF). With the 678 it cooled great but took forever to get warm in the winter.

I pinched off the hoses on the old unit when removed and pre-filled the new one as much as I could before install. When I checked the fluid after a 20 mile test run, there were some bubbles on the dipstick. Will any air vent out or should I be concerned?

And... On the gen 1 the top beehive fluid line is the pressure send port to the cooler, right? Thanks...

[VStar650CL]

There are no concerns about it venting, there's a weird looking hose that comes out next to the airbox that vents atmosphere to the transmission case. The pump should purge itself after a little driving, but if you keep seeing bubbles then it's a worry. Been awhile, but I don't think that's right about the fluid lines. I recall with the retro kits the bottom/front fitting definitely went to the bottom of the cooler, and Nissan normally engineers everything with the fluid bottom-up, specifically so buoyancy can help the pump chase out any bubbles that form. So I'm pretty sure the top/back fitting is the return. The H-valve in the cooler won't work right if it's plumbed backward, so you should pull a hose and double check.

[phmichel]

There are no concerns about it venting, there's a weird looking hose that comes out next to the airbox that vents atmosphere to the transmission case. The pump should purge itself after a little driving, but if you keep seeing bubbles then it's a worry. Been awhile, but I don't think that's right about the fluid lines. I recall with the retro kits the bottom/front fitting definitely went to the bottom of the cooler, and Nissan normally engineers everything with the fluid bottom-up, specifically so buoyancy can help the pump chase out any bubbles that form. So I'm pretty sure the top/back fitting is the return. The H-valve in the cooler won't work right if it's plumbed backward, so you should pull a hose and double check.

This is the factory cooler layout from the 2013 FSM, and this is how I plumbed mine (with a different cooler and just hoses straight from beehive to the cooler). Hose #2 coming from the top of the beehive to the top port on the cooler. Is this correct?

[VStar650CL]

That's the retro kit I was talking about. Nissan plumbs all (to my knowledge) of their factory CVT coolers and exchangers bottom-up, so I'm pretty sure 11 is the pressure side and 2 is the return. Like I said, your cooler won't work if the inlet and outlet lines are reversed (it will constantly bypass and the 'stat will never open). The inlet has to be connected to pressure and the outlet has to go to return. So you'd be well served to pop a line loose and check it, I'm fairly sure it's backward.

[phmichel]

That's the retro kit I was talking about. Nissan plumbs all (to my knowledge) of their factory CVT coolers and exchangers bottom-up, so I'm pretty sure 11 is the pressure side and 2 is the return. Like I said, your cooler won't work if the inlet and outlet lines are reversed (it will constantly bypass and the 'stat will never open). The inlet has to be connected to pressure and the outlet has to go to return. So you'd be well served to pop a line loose and check it, I'm fairly sure it's backward.

I appreciate your expertise VStar buddy. According to the Hayden installation manual for these coolers: "Fluid may stream through the cooler in either direction." The previous cooler w/o the bypass valve ran for over 40k and worked great in summer. With this new cooler the CVT heats up to around 165F in about 10-20 mins on the hwy, then just stays there (at 80+F ambient). Haven't climbed a mountain or serious hill yet but I think I should be OK. ?

The fluid still had a few bubbles on the dipstick today but I noticed it was over-filled just a tad. However - it's been at that level for 30k miles and every time I've checked the level there were no bubbles. The fluid still looks new. No discoloration. It's time for another Drain & Fill anyway so I'll correct the level.

[VStar650CL]

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.