Im a huge forum reader I have been for years and I've tried using Google to find prior aux cooler / warmer deletes or bypasses and I was unable to find them there's been talk about it but I've never read of someone successfully doing it especially doing it the way that I've done it I believe keep it simple stupid k i s s. So anyway I got the four port upgraded cooler I've done installed it I should have replaced my filter while I was doing it but I didn't however I have one ordered and on the way now I'm about to redo it all. So I installed an external transmission cooler and I felt like all it was doing was fighting the aux cooler/ warmer. There's two pretty large diameter coolant lines that run through the stock aux cooler and warmer an engines operating around 200° Fahrenheit which is too hot for a cvts ideal operating temp is 150°f so it's getting pumped in 200° or more into the side of the transmission which all that fluid is just soaking it up plus the internal heat from the transmission running itself that's just not a good combination I feel like it's a engineering flaw. The only purpose I could see it actually work would be for cold starts in the winter. So let's get down to nuts and bolts here's what I did this was an experiment just to see if it would run right for all i knew there could have been a sensor in there and the computer could have freaked out thinking it wasn't the right temperature and it might have shifted funny so I just threw some stuff together and seen if would work and it worked it shifts well definitely runs cooler. So the two coolant lines that run into the aux cooler I removed both of them from the aux ports only and I connected them both together using a double ended male connector that was all I did. All the coolant lines originally done was loop through the aux cooler / warmer anyways so connecting them was essentially the same thing it just kept all that heat from going into my cvt. So here's the test I don't have a infrared heat gun so I had to do the ole hand test. I know for a fact that after long distance driving before I did this mod I would stick my hand on my external transmission cooler that i installed and I could not keep my hand on it more than 2 seconds without it being too hot to touch. So after this mod I took it on the interstate and I was speeding intentionally going high RPM when I didn't need to and I came back and put my hand on it and it wasn't that hot I could have kept my hand on it forever. I plan on keeping this bypass throughout the summer and in the winter I'm looking at installing an electric ball valve that I will tie to a timer switch or maybe even a sensor that will automatically turn it off the coolant running to the aux warmer when it gets to a certain temperature. I know there is downsides to this mod as is currently it is not perfect however I feel a lot better knowing heat isn't getting pumped in to the side of my CVT at least for the summer during the fall I'll turn this into a different mod or maybe even reinstall as it was. Figured id share also open to ideas on how to make a 12v electric ball valve temperature operated. Im good with basic wiring thats about it. Im trying to get 300k out of this car just to say i did. Call it a mechanics challenge. Lol this transmission's been called one of the worst transmissions ever been made. If I get 300K out of it I feel like I'm doing something it's got 156,000 on it right now I've changed the fluid three times and there's nothing wrong with it shifts great. I'm trying to keep it that way and I feel like heat is the enemy

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

ideal operating temp is 150°f so it's getting pumped in 200° or more into the side of the transmission which all that fluid is just soaking it up plus the internal heat from the transmission running itself that's just not a good combination I feel like it's a engineering flaw. The only purpose I could see it actually work would be for cold starts in the winter.

150F is cool for any kind of A/T, whether it's conventional or CVT. Ideal for Nissan CVT's is 176F, most conventional A/T's want around 180F.

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

for all i knew there could have been a sensor in there and the computer could have freaked out thinking it wasn't the right temperature and it might have shifted funny so I just threw some stuff together and seen if would work and it worked it shifts well definitely runs cooler.

Only later model Sentras have 2-speed CVT's that "shift", yours doesn't. If it seems like it's shifting then you have big problems already. The TCM will only freak out if the fluid temp exceeds 220F, then it will go into self-protection and put the car in snail mode.

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

So the two coolant lines that run into the aux cooler I removed both of them from the aux ports only and I connected them both together using a double ended male connector that was all I did. All the coolant lines originally done was loop through the aux cooler / warmer anyways so connecting them was essentially the same thing it just kept all that heat from going into my cvt.

Tranny wear accelerates greatly when the fluid is too cold, just like ring and cylinder wear in an engine with no thermostat. Looping the beehive coolant lines may be fine if you live in Florida or Arizona, but it's totally unadvisable for anyplace that has any "real winter".

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

So here's the test I don't have a infrared heat gun so I had to do the ole hand test. I know for a fact that after long distance driving before I did this mod I would stick my hand on my external transmission cooler that i installed and I could not keep my hand on it more than 2 seconds without it being too hot to touch. So after this mod I took it on the interstate and I was speeding intentionally going high RPM when I didn't need to and I came back and put my hand on it and it wasn't that hot I could have kept my hand on it forever.

180F will feel damn hot to human skin. Try keeping your hand under 180F tap water. If you could keep your hand on the cooler all day then your fluid is way too cold.

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

I plan on keeping this bypass throughout the summer and in the winter I'm looking at installing an electric ball valve that I will tie to a timer switch or maybe even a sensor that will automatically turn it off the coolant running to the aux warmer when it gets to a certain temperature. I know there is downsides to this mod as is currently it is not perfect however I feel a lot better knowing heat isn't getting pumped in to the side of my CVT at least for the summer during the fall I'll turn this into a different mod or maybe even reinstall as it was. Figured id share also open to ideas on how to make a 12v electric ball valve temperature operated.

Dana and Derale already both make perfectly good 180F bypass valves that you can get for around $50. That ball valve will be a complete waste of effort.

Ls1kouki wrote: ↑

Thu Jun 10, 2021 6:34 am

I'm trying to keep it that way and I feel like heat is the enemy

Heat is your friend and your enemy. You need to control it, not stamp it out.

Thanks for the info will most likely take your advice and try to control it best i can. Im going to look into the bypass valve controlling the flow of engine coolant based on my transmission fluid temperature would be ideal i would think.

Ok so i researched the byass valve ive see these before. I agree thats a great idea however the electric ball valve i previously had mentioned was not for the tranny cooler lines it was going to go on the engine coolant output line going into aux cooler i just need a way to power it on and off based on trans fluid temp. That and the derale bypass valve would be ideal. Thatd make a steady 180° operating temp. Basically what im saying is once the transmissions up to temp id like the engine coolant lines to shut off going to the transmission. It can be done just takes research, skill, money and time. Plus i have nothing better to do on rain days. Lol

When i say my car shifts i meant changing between constant variable gear ratios. Its never slipped jerked hesitated or anything like that.

Ls1kouki wrote: ↑

Thu Jun 10, 2021 3:53 pm

Basically what im saying is once the transmissions up to temp id like the engine coolant lines to shut off going to the transmission.

It wouldn't hurt anything to kill the coolant flow, but what you really want is a reversed thermostat. Why not get a heater shutoff valve similar to the ones on older Titans and Armadas, then use an engine temperature switch to drive it? Much simpler than trying to automate a ball valve.

PS - However, I must say, with an H-valve in place the cooler will always be active when the outflow from the beehive tops 180F, regardless of how warm or cool the beehive coolant lines are. So while I see what you're trying to do, I don't see the point of it.

VStar650CL wrote: ↑

Thu Jun 10, 2021 4:12 pm

PS - However, I must say, with an H-valve in place the cooler will always be active when the outflow from the beehive tops 180F, regardless of how warm or cool the beehive coolant lines are. So while I see what you're trying to do, I don't see the point of it.

Maybe I didn't explain that well, let me take another shot. The beehive is a small and relatively inefficient heater, so a properly-sized cooler will be capable of dumping many times the BTU's that the beehive can possibly pump in. So any excess heat added by the beehive will quickly be cancelled and regulated by a short trip through the cooler (and the heat exchanger on cars that have them. Keep in mind that heat exchangers are in the outlet tank where the coolant has already passed through the radiator, so their temperature is much cooler than thermostat temperature).

I recomend anyone thinking this is a good idea to get a infared thermal temp gun and see whats really going on. After a drive my external cooler (not my aux cooler/warmer) was running 140°f with aux cooler coolant hose delete. My coolant hose running to my radiator was running 176 -180°f im going to do more testing. Starting to feel like i made a mistake possibly. deffenetely need a bypass valve for the external cooler forsure. Im going to reinstall and test the temperature difference. Im going to run two tests one normal driving and the other 3000-3500 max rpm 50-80 mph runs with delete vs reinstalled to see what norms and peak temps are. I never go over 3500 rpm even if im running late for work lol

The coolant lines running to aux cooler that i deleted were 104° i didnt originally post this number because it was hard to get a good shot at it so i didnt believe this number. However after your informational post it might just be. Im beat from work roofing in the hot sun all day im going to do extensive testing on my day off tommorow

Sounds good, but if you want a test under "worst case" conditions for comparison, I'd suggest a pull up a long hill or mountainside on a hot day, with the engine either lugging or WOT. With it lugging, coolant flow is low and engine timing can't advance much, leading to rapid heat buildup. At WOT the coolant flow is higher but the engine load and transmission belt load are much higher. I think either one would represent a fair worst-case. If I still lived in El Paso my suggestion would be Guadalupe Peak on the way to Carlsbad. Here in Arkansas the twister up Mount Nebo would probably serve.