Water pump issue

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chithi

Member
Joined
Aug 19, 2010
Messages
11
I didnot want to make this my first post to mnl, but others at the bayleaf event suggested I put this out so here goes:

I got my leaf end-aug and the next day had noticed a sound when driving and when charging that seemed to be like a loud fan. On opening the hood its source was unclear. It is a fairly innocuous noise and gets dwarfed by ambient noise so is hard to percieve when driving. However it was definitely there when I charged in my garage - with both l1 & l2.

So overcoming my lazyness I finally took it in to the dealer:
The folks there took some convincing that the noise was there - its noisy in the shop as it is and I had called in and said that I could hear a loud noise :) But the shop foreman came over and immediately identified it as the water pump. He said that if the part is available locally, they could do this is 3/4 days else they would have to order from Japan which would take 2 wks!

I attached the dealer-report for those interested, they did not have any additional details on what went wrong and only re-iterated that all leaf issues go directly to nissan-engineering. WP2 is the one on the right (just above the bumper) when you open the hood.

I guess 1 failure in 5000 is not bad, but I was a little disappointed with the experience.


The car though is great (pics below) and so is this forum!


 
smkettner said:
What makes you think it is not a normal noise? The pump and motor to circulate coolent do need to run and they all make some noise.
Good question. Mine makes the same noise and I notice it is louder in hot weather (fan speed?)
 
smkettner said:
What makes you think it is not a normal noise? The pump and motor to circulate coolent do need to run and they all make some noise.
Quite frankly I have never heard a water-pump on my other (non-ev) cars - the ice dwarfs out any other noise there :) The only thing I can compare it to is my pond's water-pump and that makes more of a 'gurgling' sound and this noise was less like a pump and more like a fan - something like a fan on gone bad on the cpu-heatsink of a motherboard.
 
davewill said:
I'd just be happy that the problem has such a clear cause. Replacing the part should be a 100% fix instead of dragging on and on...
True - I am glad that the shop foreman could identify the issue so quickly.

I was more concerned whether there could be any long term damage to the battery-pack from this pump going bad.
 
chithi said:
I was more concerned whether there could be any long term damage to the battery-pack from this pump going bad.
If there were no other warnings displayed and the car was still functioning OK, I don't think you have anything to worry about regarding the battery pack. The water cooling is for the inverter and BMS, not the traction pack, and if anything had overheated, it would have thrown an error code and stopped you from driving/charging the car, in all likelihood. It seems that they engineered many failsafe measures into the software to protect the pack from damage, and a water-cooling failure would certainly be one they anticipated, I would think. The fact that you heard noise says to me that the pump was still turning (maybe a bearing or impeller failure?) and pumping some coolant, just perhaps not optimally.

No worries, drive it and enjoy it!
TT
 
The battery pack in the Leaf is not liquid cooled like the Volt so it would have no affect on it. The pump only cools the charger.

chithi said:
I was more concerned whether there could be any long term damage to the battery-pack from this pump going bad.
 
smkettner said:
What makes you think it is not a normal noise? The pump and motor to circulate coolent do need to run and they all make some noise.

I tend to agree. Of course, we'll never know if it was REALLY bad because the shop/dealer would never come back and say "we were wrong", right?
 
Stanton said:
smkettner said:
What makes you think it is not a normal noise? The pump and motor to circulate coolent do need to run and they all make some noise.
I tend to agree. Of course, we'll never know if it was REALLY bad because the shop/dealer would never come back and say "we were wrong", right?
With any luck we will get a post after the swap with a noise reduction report.
 
For the first weeks (or month) I did NOT hear the cooling pump running when I first turned the LEAF on in the morning.

Then, I changed to 12A L2 charging from 12A L1 charging, and days got a bit warmer. Strangely, I began hearing the pump run, for a while at least, when I first turned the car ON in the garage, without even moving.

Now, months later, I charge to 80% much more often, and I will have to listen for the pump(s). Yes, I believe that there are two, both with variable speed control.
 
garygid said:
Yes, I believe that there are two, both with variable speed control.
A quick check of the service manual verifies that there are indeed 2 electric pumps. One is located under the reservoir (de-gas tank) and the other is located on the other side of the motor compartment. That's why you when you raise the hood you hear the pumps in stereo! :lol:

I noticed the pump sound all the time when I first got my Leaf, but I've long since gotten used to the sound. Now that we're getting into fall, I'll have to pay more attention to it to see if they don't run as much as during the "warmer" season. (That's what most of you call "summer", but most of us up here in the Seattle area don't figure we got one of those this year!) :)
 
I was going to start a new thread but I see that others are already discussing this issue.

My experience is that, for the first few months, I would only hear the noise of the fans/pump while charging the car, after charging the car for a while, or after driving and using regenerative braking -- at least in warm weather. In other words, I would only hear it running when it was needed. On days when the car had not been used or charged recently, the car would remain silent when I powered it up.

After a couple of months however, it started to run all the time. No matter how cool the ambient temperature, no matter how long since it had been last charged or driven (even after a day or two), as soon as I power up the car, the noise of the cooling fan/pumps can be heard. It runs constantly now. Not only is it sad (I miss my silent car), I don't like the notion of expending energy to keep that pump running all the time.

Can someone confirm for me that the car can indeed be silent as I remember? In other words, you power it up and so long as you haven't been charging/driving recently (say, overnight) and the ambient temperature is cool, you don't hear anything? Of course the climate control system should be off too. (I ask because mine's been making noise like this since like July and I'm starting to doubt my memory.)

And if the answers come back yes, it can/was/is silent, how many never get silence now? Who else starts up their car and *always* hears the same sound you hear when you plug-in for charging -- the apparent sound of the cooling fans/pumps for the invertor (and motor?)?

Thanks!
 
I feel like I have always heard the pump when I start the car and also when charging. I only got mine in early October, however, so maybe it w has been too warm to run without it. I was actually a little disappointed since I had been given the impression that the car was relatively silent. No big deal, but it's no quieter than the hybrids int neighborhood.
 
Debugging noises is often futile and frequently fruitless over the Internet, and sometimes it's so even with mechanics whose hearing may be suspect, or who has had little experience with/exposure to a particular model/area of problem.

Isn't the Bay Area crawling (probably literally! :) with LEAF's? Have you asked another LEAF owner to meet up and do a side-by-side comparison?
 
BTW, is the noise much different, or does it go away entirely, after the water pump replacement? Also, did you get any indication as to which water pump it was (other than "waterpump 2", that is)? Just gathering info... Thanks.
 
Probably the bearings in the pump were going bad. I'm also curious whether the OP got it replaced and how the process went.
 
johnr said:
Probably the bearings in the pump were going bad. I'm also curious whether the OP got it replaced and how the process went.


Not likely, there is crap in the lines form the factory that can jamb the tight pump tolerances. Mine had junk in the pump. Got a new one.
 
TomT said:
The battery pack in the Leaf is not liquid cooled like the Volt so it would have no affect on it. The pump only cools the charger.

chithi said:
I was more concerned whether there could be any long term damage to the battery-pack from this pump going bad.


I was concerned it would not cool the radio and the cigarette lighter :lol: Since the LEAF has a sealed pack that is not cooled, it is almost a given the inverter and charger would be on the same loop as in most modern EVs.
 
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