Just had coolant changed, now this crazy clicking noise...

Just got home from my coolant change at the dealer and now I have a rapid loud clicking noise which stops and starts. I noticed the noise with the car in park, so it's not from the traction motor or drivetrain. Sounds a bit like a valve rapidly oscillating. I sent a video to the dealer (too big to upload here) but the dealer is stumped. The dealer is supportive and will deliver a free loaner and tow my car in. I will let the car heat cycle overnight to see if the coolant burps which I hope might solve the problem.

Has anyone else experienced this? Or would like to speculate what the problem is, or suggestions for diagnosis?

Thanks
Knoa.

 

Thanks KiwiME! I am attempting to reproduce the problem today to see if the overnight heat cycle has burped an air bubble (although the coolant level in the reservoir did not change so I doubt it). The mechanic did say he had a tough time bleeding the coolant. He says that the dealership usually uses a special tool to suck out coolant during a coolant change on ICE cars, but it didn't work on mine. Perhaps an EV variant or adapter of this coolant sucker is the special tool referred to in the TSB? I will look for a coolant low light on my test drive but I didn't notice one yesterday.

A few more details: I didn't notice the noise until I had driven home from the dealership, about 90 minutes at highway speeds. Temperature outside was about 0C / 32F and I had the cabin heat on the whole time. The replacement coolant was the older spec low-conductivity blue 07100-J2A20. The refill used 12.5 litres which means that about 1 litre of old fluid remained and/or there is an air pocket in the cooling system.

 

After a couple of heat cycles noise is less now, more like a buzzing, but it seems to get worse with longer drives. The service manager himself delivered the loaner car and listened to the noise. You can feel the vibrations most strongly on the hose that leads to the heater core. It will need to be towed back to the dealership, unfortunately. At least the dealership's response to this problem has been excellent so far.

 

Thanks again KiwiME. I am bumfuzzled how a coolant pump can break during a coolant change. I will update the forum once more is known.

 

Yes I will keep the forum up to date on how this goes.

Charges for the coolant change were: $99 for labour, $85 per 2l jug of coolant (7 required), plus taxes and shop fees. I shopped around including dealerships in the Calgary, Vancouver and Seattle area and the price at my local dealership was among the best. FYI to my American friends - this service was actually cheaper in Canada, so it's worth considering if you live near the border.

I would also advise anyone to inquire if the dealership has done this service before. I did ask my dealership this but it turns out they lied and my car is their learning tool. Still, I would rather have this hassle closer to home.

 

Anyone know if the coolant pump is an impeller type or a diaphragm type? In my experience impeller pumps don't make that kind of noise when they fail, but a diaphragm or other reciprocating pump might.

 

Problem resolved! It was just air in the system. The mechanics at the dealership consulted their helpline and bled it one more time with good results. No more noises. All's well that ends well (and if not there is still another 40,000km warranty on the cooling system).

Too bad there was a hassle, but I was impressed with the efforts of the dealership to solve it.