Reasons to Get Hot: This is Why You Should Watch Your CVT Temperature!

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VStar650CL
Technical Expert
Posts: 8403
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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Well, folks, there's at least one Nissan dealer someplace that I'm completely, utterly, desperately ashamed of. Read this and you'll immediately see why. It's pasted from a PM conversation with @phmichel, who just saved his CVT from certain catastrophe by simply monitoring his CVT temperature:

phmichel wrote:
Mon Aug 02, 2021 2:15 pm
PAUL:
Hi again Vstar. I decided to do the CVT service at a local Nissan dealer to save time and ensure (I hope) proper fluid level. They told me they would do a flush and not a drain/fill. The service ticket says they only used 5 qts of NS3 which does not indicate to me they did a flush. ?

Also - The CVT temp (measured by the CVTz50 app) has been running 170-175f (highway) on this vehicle for the 4 years we've had it. This past year it started to go to 180+, so I thought it was time to service the CVT. Van has 83k on it (I know, I should have done this sooner). On the way home after the CVT service (1hr drive) the temp climbed to 194 and would not go below 189. It's NEVER been that high. You think this is normal? Could they have underfilled the CVT? Could they have changed some parameter in Consult that would affect the way CVTx50 reads the temp? They did reset the deterioration to 0. Would appreciate your perspective on this.

Thanks, Paul
VStar650CL wrote:
Mon Aug 02, 2021 6:58 pm
ME:
That's definitely not normal. The 194 isn't dangerously high for one drive, but it shouldn't run that high all the time. The real danger is that they may have overfilled it, not underfilled. Overfilling causes foam that will not only make it run hot, but will cause "hot spots" on the belt that will quickly destroy the fluid. Your '17 will have a leveling plug, so you can check it yourself without lifting the vehicle, just sliding your shoulder underneath. Get yourself a shallow drain pan and (I think) a 14mm box wrench for the plug. Crack the plug to finger-tight before you start, while the van is cold. Then on level ground, warm the tranny fully (160F or higher) and leave it running, slide the pan underneath and remove the plug. You should get only a thin trickle of fluid. To be safe, I'd let it drain till it stops. That will leave it about a half pint low, but low is much better than high. If what comes out is more than half a quart, the dingbats overfilled it and you should holler like hell. If nothing comes out, leave it running and add a little at a time until you get a trickle. Same deal if it's down more than half a quart, then they underfilled it and you should holler a little.

I doubt they flushed it. Lots of dealers call it that, including the one I work at, but they shouldn't because all we do is drain-and-fill. Forward flushes on a CVT are pointless and back-flushes are downright unhealthy.

This thread on another site has a great pic of the leveling plug location, it's a '15 Murano and your Quest should be identical:

https://www.nissanmurano.org/threads/cv ... ps.221288/

Sad, but I guess this proves that if you want it done right, do it yourself (sigh).
phmichel wrote:
Tue Aug 03, 2021 1:13 pm
PAUL:
So that Quest is so low I couldn't get under it far enough. Put the front up on ramps and the back on jack stands and level. Followed your procedure. Popped the overflow plug and fluid gushed out. Got 1.5 qts or so before it went to a thin line. I will be contacting the service manger at the dealer that did this.

Questions: I am concerned they put this "VG" stuff in it as a "cleaner". Have you guys used that at your shop?
Could I do a simple flush by running a case of NS3 through it while its running with the overflow plug out? Would that cycle through the fluid in the torque converter?

Again, I am grateful for your help with this. Would you be OK if I copied this conversation to the Quest forum? Might be of help to others...

Thanks, Paul
VStar650CL wrote:
Tue Aug 03, 2021 3:14 pm
ME:
I certainly have no objection if you want to copy this over, I agree that other folks will find it useful. The BG cleaner (VG has to be a typo) is pretty good stuff, although a healthy trans doesn't usually need it. It can be beneficial if you're getting Valve Body codes, since those often result from varnish, especially on neglected trannies. I don't recommend flushing of any sort. If the fluid is really degraded, you're much better off dropping the pan to clean it out and then doing a second (and third, if needed) D&F to get most of the old fluid out.

As far as the overfill, OMG. The tech who did the job needs to be hung by his thumbs, along with the Service Manager and the Shop Supervisor. It's very fortunate that you were watching the temperature and caught it, an overfill that severe can wipe out a CVT in a few hundred miles!

That last is no exaggeration, 1-1/2 quarts high is a very rapid death sentence if it isn't rectified immediately. I hope Paul gets his money back and I won't blame him for trashing that dealership very publicly on Facebook and anyplace else he cares to avail. Keep in mind, he went there because he was unsure of his own skills and wanted the job done right. The treatment his vehicle got isn't exactly criminal, but it ought to be.

The real lesson here isn't even about CVT's. It's about inept repair, and why, to whatever extent your skills and knowledge allow, you should double-check the work you paid for. When your ride behaves differently than what you're used to, investigate. I may know more about Nissans in general than you -- but you, the owner, know your particular ride far better than any tech who will ever work on it, including me. If you don't own a scanner or a trans gauge, get one, and as Obi Wan told Luke, "Trust your instincts." You don't need the Force to know when something is wrong.


Dbarry
Posts: 91
Joined: Wed Jan 24, 2018 1:23 am
Car: Nissan 240SX

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Great tip! That should save a lot of headaches.


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