CVT Temperature

JukeOnly · Apr 30, 2019

Hi Folks! Newbie here but looking time lurker.
It's the wife's 2014 SV AWD with CVT. Got the car a couple of years ago. It had 23k miles. Now it has 51K.

Did oil change and CVT fluid change today. That drain was taking forever. I got a little over 5 quarts out. Put the same amount back in. Warmed it up and shifted the car between R, N and D. The level is somewhere in the between the two notches.
All seemed normal so i took it on a test drive. Drove it in NORMAL and SPORT modes. It shifted normally. All is well.
But....i used CVTz50 for the first time. The CVT temp was running high, the highest was 207°F. The drive was a little over 10 miles. Got home, kept it running to check level. Temp slowly went down. All is good but should i be worried about the temp? Thanks in advance for your feedback.

FastReligion · Jun 8, 2020

whining is just a symptom, hell, healthy CVT's whine. Just because you dont have a runny nose, does that mean you dont have the flu? Overheating with a cooler means the CVT is bad...cant really say it any other way... As for behaving like a stock beehive, yes, it would if the system where clogged only in the cooler itself. Which would lead me back to saying theres and issue with the cooler or lines.

You have a CVT that overheats. That's already saying it needs to be replaced...
Adding a cooler to a CVT that already overheats just buys you a few thousand miles...
You have a CVT cooler that works inconsistently, that tells me the cooler design is not working.

These are things I have already said. Best of luck to you!

JukeyJukeJuke · Jun 8, 2020

You have a CVT cooler that works inconsistently, that tells me the cooler design is not working.

OK thinking bout that, how could the fluid NOT be pumping thru it sometimes. I have to investigate that.

Assuming I wanted to try a new reman CVT can u point me to a reliable source for those? There are a lot of options out there no idea what is good or not

thanks!

FastReligion · Jun 8, 2020

it should flow through it all the time. Again, Ive installed dozens of CVT coolers, and they are always warm on the face. Ive tested 5 or 6 different set ups, all of them hot across the face.

Nissan is the only place you should ever source a transmission from. You know they used oem parts to rebuild them, and you get a warranty with it.

pboglio · Jun 9, 2020

Aeration and cavitation is happening because of fluid overfill, don't overfill or overheat and it won't be a problem. The size of oil cooler you would need to dissipate the heat would need to be very large. It's easier to make a more efficient oil/water heat exchanger that uses high water flow rates, to make the exchange with the radiator. I'll be using a Laminova oil/water heat exchanger mounted at the base of the radiator with radiator coolant flow running thru the core, then a couple of CVT oil feed lines coming off a custom oil filter/thermostat adapter mount going in the stock beehive cooler location. The cvt vane oil pump will drive the necessary flow without the need for an external pump. This has enough heat exchange capacity to keep the CVT oil around 98-100 *C if the coolant is running at 85*C, even at power levels past 330 h.p. The thermostat then bypassing the cooler when it's not needed. IMHO all these other external oil coolers are a waste of time, the CVT thermal heat dissipation levels are massive at full power, almost equal to the engine's waste heat thru the cooling system.

FastReligion · Jun 10, 2020

So, your saying all the people who have had their overheating CVT helped by installing a cooler, including the OEM nissan one are wasting their time? Sorry, but the real world testing by hundreds of people and the data myself and dozens of other people have accumulated sort of prove they work. Transmission coolers are used on all kinds of transmissions. The beehive is too small to be able to transfer heat effectively using coolant. In fact, according to diagnostics I did at nissan, the beehive is actually there to help stabilize cvt fluid temps, but will not prevent the temp from rising as milage increases. On the rogue for instance: Older ones came with the Jukes style beehive, and for CVT overheating NISSAN had us install a OEM cooler as a "fix" that was basically the cvt cooler everyone installs on their jukes. As for 330 hp, no cvt Juke will ever see that power level, so no one can confirm anything about that heat. I can confirm that at the CVT limit of 267ish hp the size cooler you need with extra fluid to help maintain a good temp during WOT pulls is very large. Your system you are making osunds interesting, ad more than likely will maintain decent cvt temps, but as the CVT ages, there is nothing you can do to prevent it from eventually failing in one of several ways.

JukeyJukeJuke · Jun 9, 2020

so you havent actually done that yet, when will u have it done and tested?

as to aeration, u think that may be why my cooler is not getting any CVT fluid? I'll warm it a little and drain it tomorrow to within the hash marks. Fortunately I have a 2011 with a CVT dip stick. I wonder how to check level on the ones without a dip stick?

pboglio · Jun 10, 2020

The external oil coolers are tricky to purge the air, not sure if that's your problem or not but it sounds like you've attempted to correct it. I still think you should check the cartridge filter, if that were to clog the oil flow would be seriously restricted. I replaced mine and the oil temps went down. But the "aeration" I'm talking about is like "oil foaming". Most of the time, the fluid level is not correct. If you get it right, the CVT is very quiet, get it wrong and it will whine. It'll cause transmission overheat, oil pump pressure issues, reduced performance, etc.

The oil lube circuit is a separate low pressure circuit, so I suppose a slug of air in the oil cooler wouldn't make it's way into the valve-body directly. Anything lube related get's either dumped into the cartridge filter, beehive cooler, bearings, & pushbelt oil injection coolant jet, finally into the sump thru gravity. The lube circuit relief valve inside the valvebody dumping anything back to the sump if the coolant circuit become obstructed. I'll have to review the lube circuit again. It sounds like the oil flow in the cooling circuit isn't there, the cartridge filter I'd check first. These cheap coolers also have some decent pressure drop, combined with small oil hose diameter, might cause a problem.

As far as my setup, I haven't run my setup yet, I'm hoping by end of fall but it won't be in time for the summer temps. It's been about almost 2 years on build/development.

The engine is in the final stages of machining process to rebuild it, re-polished crankshaft, upgraded forged rods, upgraded forged pistons, RS oil pump, RS rod bearings, cometic head gasket, the cylinder head is fully ported w/3 angle valve job, custom upgraded springs/retainers, upgraded Crower regrind cams. The CVT is fully rebuilt and upgraded with: Rebuilt/reman CVC torque converter, custom higher capacity 4-clutch forward clutch packs, improved clutch pack release gap clearances, upgraded high torque pulley sheave axial bearings (i.e. cobalt slider pin vs. 6mm ball bearings), upgraded Sonnax oil pump flow regulator valve w/brand new OEM oil pump, brand new valvebody (OEM), latest TCM reflash, custom reinforced forward clutch drum (pending the machine shop), latest factory updated CVT pushbelt 90183, running the high torque AMSOIL synthetic CVT fluid. That's what's done already sitting on the bench, minus the reinforcement insert for the clutch drum I designed, that'll take another couple months to retrofit. The custom Laminova CVT cooler will also have a full flow oil filter like an engine oil filter for improved filtration capacity, plus the oil pan has an additional pan magnet installed already for improved debri pickup. That custom oil filter mount I rapid prototyped and it's sitting on the transmission sitting on the bench, need to get off my butt and send it to the machine shop but it's lower priority for now. Most guys don't know but the stock CVT filter can restrict the oil cooler.........then the oil temps get out of control. When I swapped mine my oil temps dropped, so something to watch out for on maintenance. My solution will make oil filter changes a snap, plus have much higher capacity for filtration.

The CVT filter housing is custom machined, uses a Setrab oil thermostat & Setrab oil filter mount, plus an automotive style filter w/14 micron rating. The Laminova cooler (not ordered yet) mounts at the base of the radiator, replacing the stock radiator hose plastic joint fitting & mounting point and slips neatly in it's place with minor trimming of the radiator hoses. The Laminova cooler is like a super-beehive cooler, much more efficient. I relocated it so I had room for a bigger oil filter, and cause it looks baller......lol. Anyway, all the radiator water flow passes thru the oil cooler, while the CVT oil is pushed thru in counter-flow using the stock CVT oil pump. The CVT oil then stays at between 85*C and a max of about 98*C or thereabouts. Kinda important to keep the oil warm in that range in terms of oil flow and where it needs to get to actually lubricate and flow correctly thru the many orifices. The setrab fanpack cooler is there actually the engine oil cooling instead, which will take the heat load off the engine and give some back to radiator cooling capacity back to the CVT, or I'll run it in parallel with the stock engine oil cooler.

squirtbrnr · Jun 10, 2020

I see you've met the resident thermodynamics expert and mechanical system design guru @pboglio .

Then let me throw this into the mix. 2013 SL AWD with 82.6k miles, tuned and beaten as a daily driver albeit 90% city driving and not a single CVT issue. Ever. Not even limp mode caused by the CVT (my posts years ago about high revs or cutouts on the interstate and not moving were caused by overboost and a failed boost control solenoid combined with a failed tune). Sure I have already had 2 drain and fills and plan to do the third before I reach 100k miles. I don't have a CVT cooler. I don't log my temps. I see no reason for me to get one at this point. Sure some say it's "insurance" to delay when the inevitable happens, but I've seen more anecdotal posts about problems either installing or with one installed.

FastReligion · Jun 10, 2020

99.99% of people do not track their jukes. So all the R and D being discussed is for a road car to prolong life. I would never ever waste my time making a CVT cooler for a race track. Lars Wolfe tried for years and finally just did a six speed swap, it was cheaper and easier than re-engineering a CVT.

The OP definitely is not tracking his car, so all conversation in this thread is about a road car, and problem/solutions associated with that.

I am excited to see what you can accomplish with a more sophisticated system, don't get me wrong, but the applications are apples and oranges for what you are trying to accomplish. There is a proven system available in a dozen places online to help the OP.

I would love to see your designs for your cooler, it sounds like it would be a blast to make, and i hope thats how it turns out for you.

pboglio · Jun 10, 2020

I know he's not tracking it, but the point is that even a track setup can be used on the street. I'd almost recommend going back to stock and checking the filter and beehive cooler or just replacing them, also checking the CVT coolant thermostat which wasn't mentioned.

Yeah, I seen Lar's car. I know nothing about Rally cars or how to build them. In some areas, impressive build, in other's....not what I would do. Because he tried and failed, that's him. He's not an engineer......I am. I disassembled the JF011E and targeted each of it's weak points, including the cooling system. I designed it to be bullet proof on the street, time will tell if it works. If it can see a track day here and there or an auto-x without burning up the transmission, that's a bonus. A stock CVT car has no chance on the track based on the couple of articles I read of those that tested them. They can barely hold together on the street with mods. I built my car for durability, couple tracks days, auto-x, commuter car.

Bulldog281 · Jun 10, 2020

YEP, Matt is 100% right on this one. The Jukes CVT are a ticking time bomb waiting to deteriorate. My daily is running terrible right now due to overeating and causing the cvt fluid viscosity to sponge + foam internally. Im fixing to re-service the CVT actuator modules and completely drain out the old fluid out of the cvt unit on my daily. My cvt didn't even make it to 50,000 thats some sad S**T.

Stick shift juke transmissions are way better and last longer.

Bulldog281 · Jun 10, 2020

I would put the cvt cooler off to the left side and not posteriorly behind the intercooler. Sorta like Porsche and Bentley equips their vehicle. Better air flow, plus you can probably get a fabricated air vent for direct air flow to the cooler as well. Thats a nice diagram thought man, Thumbs up(A+)

Bulldog281 · Jun 10, 2020

Also if that pump fails that you sandwich between the cooler and the lower main radiator hose, then you can kiss your cylinder head goodbye. I would stick with the OEM Nissan non restrictive CVT fluid route.Ive changed a lot of CVT thermostats or just simply delete them and put a straight hose.

pboglio · Jun 10, 2020

It's not a pump, it's a water/air heat exchanger. My head is totally safe, trust me. There is no restriction to coolant flow in normal full flow configuration, though it can be throttled with restrictor caps to gain oil cooling performance, it's difficult to explain the process. The Laminova coolers are intensely efficient due to their .010 or less thick cooling fins which are cut from a billet rod using some fancy shmancy electrode wire cutter, they pack 2x the cooling capacity for an equivalent front surface area, fins transfer heat better because there is no brazing joint, plus they are like a rolled up radiator core so they are super compact. Anyway, very pricey for the special dual core I have shown but I needed the most compact solution for the highest cooling potential. The Setrab oil cooler you see has nothing in front of it except a pressure feed duct, the 2J FMIC is in front of the radiator.

I'll also be trying in the future a rear differential cooler which actually will need a small pump, a modified fuel pump for oil actually, that'll get fitted in the rear passenger fender well. Mishimoto did that on their Ford RS with outstanding track results. Seems the RS was going into thermal protect due to the rear end overheating the clutch packs. The Juke would probably enter limp mode if the AWD-V were active the entire time on a road coarse, the exact problem the Ford RS had.

And so, because I have an expensive built motor along with a completely customized expensive CVT transmission to protect, I'm going a little bit overkill.

Bulldog281 · Jun 10, 2020

Yeah I would put that little guy up in the front where its exposed to direct air flow. Laminova cooler are good but expensive. I have one actually welded internally on a manifold on my H22 for my Supercharged Prelude. The Laminova coolers is cooled by direct water flow from the windshield washer fluid recirculating with a motor pump. Good idea man (A+)

pboglio · Jun 11, 2020

Yep, thanks. Front was an option but the coolant hose routing makes it more convenient to mount it behind the radiator.

Bulldog281 · Jun 11, 2020

Not a problem, that’s a great idea. Also if limitation is due to a rubber hose you can use nylon stainless steel braided hoses and you can route the hose to the front. That’s what I’m using and they hold up really sturdy. A legit spool for AN 6 is expensive but it’s worth it. Stainless steel nylon hoses are more heat resistant and durable against grime and oil corrosion.

SamusFarron · Jun 26, 2020

It's such a complex issue because you want to keep it cooler, but not too cool because the CVT relies on heat to kind of activate the fluid and provide the appropriate grip efficiency with the belt and lubrication capability with the pulleys and other components. It seems like the CVT would be happiest perpetually at 85c but that's probably nearly impossible to achieve using any means.

I have been considering an external cooler but it seems the results are mixed, even using the OEM one that is stock in other markets. Even seen some people say that they saw an increase in temperatures after adding auxiliary cooling radiators with fans. A few years ago I had an idea of attaching some sort of heat sinks, but really at that point you might as well just have a custom CVT pan fabricated that has lots of fins and surface area - but who knows if even that would help.

One thing that has also kept me from adding one using that beehive with the four ports is that I would be concerned that by the time you are adding a large enough additional radiator to really drop the temperature that you might be adding so much additional stress to the pump that you are negating the wear and tear benefits you are after.

It's too bad that all these years later there still isn't a consistent and reliable way to manage CVT thermals. I like the CVT - the torque vectoring alone make its worth it and even in pure driving characteristics it actually has some really positive attributes that you grow fond of like having that nice smooth power available coming out of corners; but the once in a blue moon mine kicks into protect mode I feel like I am killing it and really yearn for a way to prevent that.

pboglio · Jun 27, 2020

The factory are mainly worried about the power loss in pumping the colder oil and also pumping thicker oil, though the thicker oil will cavitate in the pump which is bad too. This is why they are running lower viscosity oils now and doing all they can to turn the oil pump pressures down, even as far as going electric auxiliary oil pumps for on-demand requirements. I'd say 85*-90*C would be ideal but not totally sure.

The Beehive cooler is doing most of the cooling, but it's still not efficient enough. The auxilliary cooler is splitting the oil flow. This can be good or bad depending on how good the oil cooler is and how restrictive it is. Some guys have completely bypassed the Beehive and did see higher temps. Let's say an oil cooler has it's oil flow cut to 50%, it's thermal heat transfer get's reduced to 70%, something like that. Thus if I now have equal (2) coolers in parallel I split the oil flow 50/50 % but pickup 70% + 70% of the total Btu/hr capability. So I'm still up +40% over what I had or 140% of the original heat transfer capacity. That's IF the oil flow is split evenly, and IF the heat transfer capability are also equal. Too many unknowns for that to be correct unless the coolers are identical, and a Beehive and auxilliary oil cooler are no where near identical. Now that I think of it, having a restrictive auxilliary oil cooler is probably MORE beneficial on this type of setup. Running an unrestrictive auxiliary oil cooler could potentially pull a lot more oil flow away from the Beehive without a lot of Btu/hr to go with it, which is exactly what you don't want to do.

More than anything else, this is probably why you see such inconsistent results, since it's a balancing act of oil flow restriction/throttling and thermal capacity of the auxiliary oil coolers.

Macgyver · Jun 28, 2020

If it was me. I would try to source the cooling plate instead of the 4 pipe beehive. We heard they mite leak but the flow has to be better as the channels are bigger as well as the lines / fittings.

JukeyJukeJuke · Jan 4, 2021

Ok here's an update. CVT temps are running usually BELOW the engine coolant temp. The CVT's heat must be going somewhere and when below coolant temp and I think this shows the front cooler's effect and that its not enough in summer. When it was 80 degrees out, the cvt temp was much higher. I was just surprised to see this.. This is in 30 - 50 degree weather and a lot of highway.

Jaxxa · Jan 5, 2021

I've been using the CVTz50 app for a while now and this is exactly what I'm seeing most of the time too. Ambient temp below 50 and the cvt seems to be very stable at around 180-190F, but when it's 75-80 or hotter outside, I get to 194+ after about a half hour of highway driving.

JukeyJukeJuke · Jan 7, 2021

It's been a while, but someone further up discussed about the cooler pump oil pan solution and added some interesting thoughts. But as far as I am concerned, if the CVT can stay nice and cool at 75mph on the highway when its below 50 degrees out, adding enough external cooling should achieve that same result. the CVT has been running below engine coolant temp, so it would seem the beehive is ADDING heat to the CVT fluid. So it must be that my external cooler is working.

BTW, does anyone else see their CVT temp lower than engine temp even after a long drive?

Jaxxa · Jan 7, 2021

Mine will eventually always get hotter than engine temp. From what I've read in other threads it seems like this is pretty common, of course not everyone can check their CVT temp on demand, so whether or not some people's CVT's stay cool or other people's CVT's roast themselves is hard to say. It makes me wonder how many people could have prevented destroying their transmissions if Nissan would have just put a CVT temp gauge in the dash, I certainly drive my Juke differently because of it.

Jaxxa · Jan 8, 2021

He was a nissan technician for a long time and has worked on a lot of people's Jukes specifically, but the way he explains it sounds like he was trying to cool the fluid down to ambient temp, which of course if you are trying to cool CVT fluid down to like 60 or 70 degrees it's gonna be a huge problem. All you need is a reliable way to cool it about 30 degrees maximum, and a thermostat can handle the duty cycle to keep it from overcooling the fluid. As far as evenly distributing the cooled fluid, I think introducing it into a spot where it is closer to the primary pulley should probably be best (but of course low enough to be always full of fluid and not take on air), since it's the spinning action that pumps fluid into the beehive cooler (from what I've heard) makes sense to me since both of those things are toward the front. I read through this thread a while ago but I've been doing a lot of my own research into how CVT's operate, so I know a lot more now than I did 6 months ago.

One problem I just realized that he probably ran into but didn't mention, He opted to have the pump not full of fluid when the CVT is not operating, which he said caused aeration. But even if we keep fluid in the system the whole time, when the pump is off, that fluid will continue to cool and not circulate through the transmission, so instead of stopping the pump completely when not in demand, it has to be ran at a lower rate so it can still idle fluid through.

I am kind of interested, but really don't want to go tapping holes into the oil pan of a vehicle I daily drive. There are some less invasive options I want to try out first, personally

pboglio · Jan 10, 2021

Well, here is how the stock CVT cooling system works. Oil is picked up from the sump by the oil pump. Then it's fed into the valvebody so it can split the flow to hydraulics (clutches, pulleys, etc.) then another low pressure circuit is used for lubrication & cooling, about 75 psi or so. This then hits the oil filter/cooler, then hits the CVT belt injector and roller bearings. That then falls into the oil pump and it starts all over again. IF you run an external pump and cooler, you are simply running a parallel circuit that is ONLY dedicated to cooling. There is ZERO lubrication in that circuit because it's not tied into it. This works because the oil pump can now draw from the cooled sump oil which will help it out if all other things are equal.

Follow me on this guys, OIL FLOW is what keeps the CVT alive. When you replace the clogged oil filter on a CVT......it doesn't tend to overheat because you have increased oil volume to extract the heat. I did that and AMSOIL and I could not get it to hit limp mode when previously it would do it almost every time without mercy. I'll preface that it was mainly the wrong oil fluid LEVEL that caused overheating and cavitation, but the higher oil flow definitely helped even better with oil cooling. When the CVT wears out, then it overheats no matter what you do. I'm not saying this will solve all problems, but how many guys have their oil filter in perfect condition & their CVT fluid levels perfect? I guarantee this isn't a common condition so you have to be meticulous about that and the CVT oil level has to be bang on.

Hopefully that's clear, just because you slap an external pump on does NOT mean you increased oil flow to the things generating heat. If I did that and drastically cut the lubrication circuit flow for the lubrication circuit, the entire CVT would die very quickly even with an external oil pump and big cooler. The CVT oil pump has to push large volumes of oil flow in the lube/cooling circuit just to keep the belt and bearings alive, cooler is better but oil volume matters too.

Here's another one: Too cold and the oil pump starves and cavitates because the oil is too thick to pump.....very bad. Too HOT and the oil level rises due to thermal expansion and the belt whip aerates the sump oil.......and cavitates the pump, and you lose belt pressure. This is why when you nail the oil sump levels perfectly........magically the CVT stops overheating and whining. I live in Chicago so maybe the western states things are different.

It's possible a slug of air in an external oil cooler that dumps oil directly under the oil pump pickup might aerate the oil. I think it's B.S. but I haven't tried it. The CVT belt itself is churning the oil like mad and normally this is OK as long as the oil level is bang on perfect. This is the primary reason the oil pump cavitates but thick oil can do it without any air in the oil sump, so can a stuck oil pump flow relief valve which is it's main job to control pump cavitation. This is my point, there are many things in the CVT that can fail over time that will overheat it, this is a mechanical problem.

Why that setup didn't achieve it's goal? It was a false idea that reducing the heat would somehow magically increase belt traction. Heat does cause slip due to cavitation, but that's not going to increase the belt traction beyond normal levels. You want the oil temperature not too cold and not too hot, so I'd say that 194*F is a pretty darned good target if I had to pick one.

I'm not saying the external coolers aren't needed. I'm saying lot's of times it's a crutch for an existing problem. Fix the problem first......then add the cooler and you now have an even better setup.

Bargeld · Jan 10, 2021

Just one of the reason I haven't done am external CVT cooler. The risk of introducing problems is more than the return of the cooler.

Regular & early fluid swaps at a dealership are a better solution for me.

squirtbrnr · Jan 10, 2021

Same here. I thought about doing an external cooler because I’m tuned but instead I stick with CVT drain and fills at the dealership every ~40k miles. The added risks of modifying the existing CVT fluid system outweigh the rewards for me.

Jaxxa · Jan 11, 2021

I feel like that is a very detailed explanation as to why we all have seen such little returns with our CVT coolers. I will say that when I was having my beehive cooler swapped out I suggested to the tech to swap in a new CVT oil filter, and they said I probably didn't need it, and I'm thinking I probably should have pushed for it a bit more.

CVT Temperature

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