4th water pump failures in the last 1.5 years.

2015VolvoXC60 · Post by **2015VolvoXC60** » 12 Feb 2025, 18:57

My 2015 Volvo XC60’s water pump recently failed. Just stopped running. I replaced it with a new one and all is fine. This is the 4th water pump I’ve installed in the last 1.5 years. The last one ran 7 months. After opening the pump I found several electrical components on the circuit board burned up. If I open the previous water pump, I’d guess it too has burned components. What could possibly be burning out water pumps? Fuse is correct, 30 AMP and fuse has not blown once. I have found no recall info and no similar issues with this same make/model. Taking car to see if any codes are stored tomorrow. Head scratcher.

2015VolvoXC60 · Post by **2015VolvoXC60** » 12 Feb 2025, 23:23

A few images. Note the burnt components on the circuit board. Q3, Q5, Q8 Transistor or MOSFET are burned up.

Post by **Blacklab467** » 13 Feb 2025, 17:42

I have to ask; are you using “brand -X” parts or genuine blue box Volvo parts. Seems to be a very high failure rate.

2015VolvoXC60 · Post by **2015VolvoXC60** » 15 Feb 2025, 18:57

The first replacement water pump was a Volvo, per the mechanic. Made in Germany. There is no Brand-X or any other brand name on the pump. The second replacement was from Amazon, it came in a plain white box. No name. No brand or country of origin. The 4th replacement is from Rock auto. It also arrived in a plane white box No name. So, there appears to be no brands. It’s likely they are all made in the same factory. Both the Amazon and Rock Auto pumps came with a warranty. So, weather it’s a Volvo brand or the plain white box brand, 3 have failed in the last 18 months and I’m at a loss as to why. No error codes, check engine light, no indication whatsoever as to why these pumps are failing. I’m on the 4th pump. It’s running fine right now but who knows, in a month, 3 months, or 6 months, this one too could fail.

Post by **matthew1** » 15 Feb 2025, 19:25

Did you talk to the dealer parts desk when the Volvo pump blew? I think they would do something. Return, swap out, etc.

Post by **abscate** » 20 Feb 2025, 05:30

2015VolvoXC60 wrote: ↑15 Feb 2025, 18:57 The first replacement water pump was a Volvo, per the mechanic. Made in Germany. There is no Brand-X or any other brand name on the pump. The second replacement was from Amazon, it came in a plain white box. No name. No brand or country of origin. The 4th replacement is from Rock auto. It also arrived in a plane white box No name. So, there appears to be no brands. It’s likely they are all made in the same factory. Both the Amazon and Rock Auto pumps came with a warranty. So, weather it’s a Volvo brand or the plain white box brand, 3 have failed in the last 18 months and I’m at a loss as to why. No error codes, check engine light, no indication whatsoever as to why these pumps are failing. I’m on the 4th pump. It’s running fine right now but who knows, in a month, 3 months, or 6 months, this one too could fail.

If it didnt have the Volvo part number on it it is a counterfeit or aftermarket. OE is Pierburg but Volvo part numbers will be on the casting somewhere

Post by **pgill** » 22 Feb 2025, 11:22

How much do you want to know about how a brushless DC motor controller works?

I am going to explain what I can but before you read all of that the most likely cause of the problem is not the water pump but something external

For example

- faulty wiring or intermittent power can cause the circuit to stop working and fail like yours did

- if the circuit board is extremely hot it could also cause a failure. Make sure that cool air is getting to the housing per the original design intent

The 3 phase brushless DC motor

If you look closely at the circuit board you will see that the three phases are labeled. U V W
The circuit is switching between the the three phases sometimes Battery + is connected to the phase and sometimes Battery- is connected.

If you look at the failed device you will see that the circuit board actually has 6 of these devices and three of them are facing up and the other three are facing down.

By switching these devices (Transistors) current can be injected into the phase or it can be removed from the phase.

Because you have three phases each device is only being used 33% of the time and if you look carefully at the input pins you will see that one is labeled PWM (pulse width modulation) which will limit current even more. If the PWM is 50% then the device is actually on half of the 33% or 16%

Why does this matter?

If the motor controller stops switching but leaves the transistors on then the current flow becomes 100% instead of 16% and the transistors get too hot and they fail as you have documented

For reference if the problem was isolated to a single transistor that just stayed on then the failure would be between that transistors and its neighbor because the current flow would be directly from power to ground without going through the motor winding. You don’t have this failure mode which indicates that the controller circuit stopped working. (loss of commutation)

If I were looking for the root cause of this problem I would look for an external problem like a bad power or ground connection or a relay that intermittently switches on and off

Good luck

Paul