If your belt is slipping, which it sounds like it is. I’d service it , today and start shopping new and or used cvts. The only failure I ever had was on an 09 under extended warranty that started whining. The dealer thought a service would fix it but I pushed for the tranny. I never changed cvt fluid, didn’t know. It went out at 95k. That replacement tranny is as good as new at 75k, but I also learned and replaced fluid every 10-20k. Heat kills the fluid and Nissan never tells you that, why I have no idea.

VStar650CL wrote: ↑

Wed Aug 25, 2021 4:19 pm

I have to revive this thread because I have a Blue Light Special in the Live-and-Learn department. Some of you may have noticed I just installed a CVT temperature gauge on the wife's '13, mainly because I got tired of using my phone for an instrument panel. That CVT has always run 160~170F in hot weather, 140~150F's in the winter. We've had the car for 70K and it gets new fluid every 20~25K, and it's always run at those temps. Not that 170F is harmful, but I kept noticing that D1dad's Altie and a lot of other forum folks generally saw temps 20F or so cooler than that. My customers who watch their temps generally ran a bit cooler too. I wondered why, so along with installing the gauge, I started poking around looking for a reason. Lo and behold, I discovered that the embedded thermostat that's supposed to shut off coolant to the beehive was stuck wide open, not just a bleed-flow when warm like it's supposed to. So it was dumping hot coolant into the beehive all the time, not just when the tranny needed warming. It's probably been that way since we bought the car. I changed it out and presto, 140F on flat highway instead of 160F, 150F in the hills instead of 170F.

That's like -- c'mon, man. That 'stat is something nobody ever thinks about. Lots of techs don't even know it's there.
Now I'm wondering how many cases of "repeated failure" might owe something to that butt-stupid little valve.

Reviving this old thread.. there is definitely a wealth if info here, shared by VStar650.

I have had my 2014 2.5L since new, and I have replaced CVT fluid thrice in 80k miles. I have Hayden bypass cooler installed in-line with the radiator oil cooler, which activates at 180F, so its not used most of the time. I have noticed that CVT runs at 125-130F on highway drive, when its 30F outside. It runs at 150-165F on same highway drive, when its 65-80F outside. So there is a direct correlation of CVT temperature to outside air temperature. Engine coolant is always between 180-195F.

I live in Boston, in winters CVT takes good 15-20 miles highway drive to even get to 125F; in short trips lets say city drive of 5-6 miles, it barely reaches 80-100F.

I have noticed that if I sit in traffic, the CVT temperature starts climbing quickly, even in winter. In a recent trip, I was on highway with CVT at 130F, after that I sat in traffic for 20 mins, CVT temperature gradually climbed from 130F to 185F. My gut feel is engine coolant is dumping heat in the CVT fluid.

I believe there are two point where engine coolant sends heat to CVT (1) Beehive (2) Radiator bottom tank. Beehive thermostat may be closed (so no hot coolant going to Beehive), but Radiator bottom tank is still heating up the CVT fluid, when Radiator is cooling the coolant. The Radiator bottom tank is around 180F, and that's always heating up CVT fluid.

As per my understating, Nissan has designed the system to keep CVT fluid around 180F (Radiator bottom tank temperature).

Let me know if I am thinking right.. some of you senior guys like VStar650CL, definitely know a lot.

The outlet tank, which is where the heat exchanger is located, will run a lot less than 180F unless the cooling system is very stressed. The radiator's job is to dump heat, and the coolant in the outlet tank has already passed through the fins. I've also discovered that the CVT thermostats operate like a normal 'stat, which is opposite what I was originally told and seems completely nonsensical. In essence, Nissan is heating up the fluid endlessly with no thermal limitations or controls, then relying on the exchanger to counteract the excess before it gets back to the tranny. To me, that's a Blue Light Special in the "I Don't Get It" Department.

Anyway, in real life, your 180F cooler isn't doing you much good. It will drop the temperature when it cracks, but the 185~190F that results is already above optimal, which is in the mid 170's. The trouble is, the fluid in the pan and hive has thermal mass that the cooler needs to overcome after cracking, so the steady-state temperature will always be above crack temperature and it will always go too high before it levels out. I've switched to a Hayden 697 on the wife's Altie and it's much better, with a crack temperature of around 160F. That also works better with my self-designed CVTsaver, which replaces the thermostat with a temperature-controlled poppet valve that kills flow to the hive above the 170F's. For the cooler, another very good alternative is to swipe one from an R52 Pathfinder in the junkyard, those crack in the 140F's because they're specifically intended for towing.

VStar650CL wrote: ↑

Tue Mar 05, 2024 7:45 am

The outlet tank, which is where the heat exchanger is located, will run a lot less than 180F unless the cooling system is very stressed. The radiator's job is to dump heat, and the coolant in the outlet tank has already passed through the fins. I've also discovered that the CVT thermostats operate like a normal 'stat, which is opposite what I was originally told and seems completely nonsensical. In essence, Nissan is heating up the fluid endlessly with no thermal limitations or controls, then relying on the exchanger to counteract the excess before it gets back to the tranny. To me, that's a Blue Light Special in the "I Don't Get It" Department.

Anyway, in real life, your 180F cooler isn't doing you much good. It will drop the temperature when it cracks, but the 185~190F that results is already above optimal, which is in the mid 170's. The trouble is, the fluid in the pan and hive has thermal mass that the cooler needs to overcome after cracking, so the steady-state temperature will always be above crack temperature and it will always go too high before it levels out. I've switched to a Hayden 697 on the wife's Altie and it's much better, with a crack temperature of around 160F. That also works better with my self-designed CVTsaver, which replaces the thermostat with a temperature-controlled poppet valve that kills flow to the hive above the 170F's. For the cooler, another very good alternative is to swipe one from an R52 Pathfinder in the junkyard, those crack in the 140F's because they're specifically intended for towing.

I have Hayden 696 installed, I thought it opens at 180F, good to know its 160F.

Another observation, I have babied the car since beginning, installed cooler and did fluid change with Nissan NS3.. simply because, soon after buying it new, I realized the CVT was not very robust. But despite all that the CVT had developed noticeable vibration and noise. So, I intentionally switched to Valvoline CVT fluid (its NS-3 compatible), as its a little thicker fluid (higher viscosity).. and that did take care of a lot of noise/vibration. Now CVT is much smoother.
I know, its strongly suggested to stick to Nissan NS3, but in my experience, that fluid is too thin (low viscosity) to protect the CVT properly, and is probably one of the cause behind a lot of CVT failures.

Yah, I contacted Hayden and they told me the 69x's all open at 160F. There wasn't anything in the literature, so I took their word for it. The one in the wife's car was new last fall, the hot weather will tell if they were lying to me.

NS3 is a good fluid but very noisy. It's formulated for gas mileage and not quietude. Valvoline is actually pretty noisy too. If you really want quiet, try Eneos or AMSoil.

VStar650CL wrote: ↑

Tue Mar 05, 2024 10:16 am

Yah, I contacted Hayden and they told me the 69x's all open at 160F. There wasn't anything in the literature, so I took their word for it. The one in the wife's car was new last fall, the hot weather will tell if they were lying to me.

NS3 is a good fluid but very noisy. It's formulated for gas mileage and not quietude. Valvoline is actually pretty noisy too. If you really want quiet, try Eneos or AMSoil.

surely, next time AMSoil.. its also a thicker fluid, so should help with vibration/judder.
In my opinion, as the vehicle age.. with wear and tear the clearances/gaps between various moving parts increase.. so higher viscosity fluids typically do a better job of protecting, be it engine or transmission, I recently switched to 5w30 in engine from 0w20, which I have always used in past (ofcourse at the cost of mpg).

Don't go thicker than 5W, you'll start getting P0011's in cold weather. AMSoil isn't really much thicker, it actually has a much lower cold pour point than most of the competition and I recommend it to anybody who lives in the snow belt. CVT's are just glorified friction-drives, and all CVT fluids need to be compromises between allowing belt traction and keeping metal off metal. Those ends are obviously somewhat opposed, so the fluids have some very special properties to walk the knife edge of that compromise. Some do it better than others.

VStar650CL wrote: ↑

Tue Mar 05, 2024 11:52 am

Don't go thicker than 5W, you'll start getting P0011's in cold weather. AMSoil isn't really much thicker, it actually has a much lower cold pour point than most of the competition and I recommend it to anybody who lives in the snow belt. CVT's are just glorified friction-drives, and all CVT fluids need to be compromises between allowing belt traction and keeping metal off metal. Those ends are obviously somewhat opposed, so the fluids have some very special properties to walk the knife edge of that compromise. Some do it better than others.

Thanks for the advice!
one more observation, I have noticed that when CVT is at 180-190F (which is not very frequently), there is CVT fluid smell, I can smell it inside and outside, near the hood. I noticed this after changing over to Valvoline (last 3-4k miles), never before. Any idea what's going on ?

There's a J-shaped vent hose on the CVT which comes up on the righthand side of the airbox.

VStar650CL wrote: ↑

Wed Mar 06, 2024 7:24 am

There's a J-shaped vent hose on the CVT which comes up on the righthand side of the airbox.

What do I need to do with the vent hose ?

Nothing, but the smell is probably coming from there. The fresh air intake is about 18" away from it under the cowl, so any smell coming out of the vent would undoubtedly make it inside the cabin. If you didn't DIY the last fluid change, make sure they didn't overfill it.

VStar650CL wrote: ↑

Wed Mar 06, 2024 9:24 am

Nothing, but the smell is probably coming from there. The fresh air intake is about 18" away from it under the cowl, so any smell coming out of the vent would undoubtedly make it inside the cabin. If you didn't DIY the last fluid change, make sure they didn't overfill it.

Thanks much!

Can I ask your opinion on a totally off-topic thing.. since you are a tech. Couldn't find a way to send you an IM, so posting here.
Any thoughts/experience with Acura MDX (its a Honda Pilot clone) ? I am looking for getting 2020 MDX.

Nope, sorry. I'm strictly a Nissan guy and they don't make me do used car UVI's anymore.

I’m at 79k on the wife’s rogue, just drove 600 miles round trip to northern kentucky and back. I serviced the cvt with 5qts of Lubegaurd complete prior and saw higher than normalish cvt temps. Generally 180-200 in hot weather and hammering down through the hills. The occasional 215 reaching the top of a mountain. This time I averaged around 200 the whole time. I still have 6k left on the extended warranty, but will for sure add an extra cooler after. The trans has never sounded better that with Lubegaurd, but the cvt did run a few degrees hotter with the fluid for some reason.