[pugguppy]

I recently purchased a used 2017 Bolt at 36,000 miles. At the lot, I checked under the hood after my short test drive to find that all coolant levels were normal. I drove it 180 miles home and began charging it. I looked under the hood again to find that the coolant in the center had dropped about an inch. Could this be due to the fact that I'm charging it or do I have bigger issues at hand? I don't see any coolant on my garage floor.

 

[XJ12]

I looked under the hood again to find that the coolant in the center had dropped about an inch.

Welcome to the forum. Fluids change volume with temperature. Possible your drop is due to the fluid being colder than when you previously checked. Keep an eye on it though.

 

[sbachman7117]

I don't see any coolant on my garage floor.

I think the concern would be that the cooling system within the HV battery assembly is leaking. In that case, the battery housing would contain the leaked coolant, so it wouldn't be apparent externally.

 

[pugguppy]

I think the concern would be that the cooling system within the HV battery assembly is leaking. In that case, the battery housing would contain the leaked coolant, so it wouldn't be apparent externally.

If this is the case, would it be covered by the warranty?

 

[GJETSON]

If this is the case, would it be covered by the warranty?

I am pretty certain it would be. The battery cooling system is essential on this EV, and you could not charge it without a functioning cooling system. I would keep an eye on it. If it continues to go down, the blue thing is a level sensor on the reservoir. If it gets too low, it will throw a code, and the dash will say you can not charge.

I just went out to check ours sitting in a cold garage overnight. It is a 2017 with 35K miles, and I have never added coolant. The battery reservoir is a half inch above the line. The power electronics reservoir is one inch above the line, and the cabin heater reservoir is on the line.

 

[sbachman7117]

If this is the case, would it be covered by the warranty?

If the leak is inside the battery, I can't imagine any argument against it being covered by the 8-year/100K warranty.

 

[drdiesel1]

Fill it to the correct level with deionized water and keep an eye on it.

 

[wesley]

I second keeping an eye on the levels, but advise against adding deionized water as it would dilute the fluid. The level definitely fluctuates as it circulates and is affected by temperature. I’ve seen it dip slightly below the line even when it was new.

 

[Sean Nelson]

I photograph the four fluid levels (three coolant, one brake fluid) periodically to act as a record. I've never seen any of them budge since the car was new. If one of them went down an inch on me I'd be all over it trying to figure out what happened.

 

[cwerdna]

I second keeping an eye on the levels, but advise against adding deionized water as it would dilute the fluid. The level definitely fluctuates as it circulates and is affected by temperature.

Ditto. Also, on page 262 of my '19 Bolt manual it says:
"Hybrid Cooling System
Pressure Caps
The hybrid cooling system
reservoirs have tamper resistant
pressure caps. The coolant should
only be serviced by a qualified
technician."

Also page 261 says:
"It is not necessary to regularly
check coolant unless a leak is
suspected or an unusual noise is
heard. A coolant loss could indicate
a problem. Have it inspected and
repaired by your dealer"

I recall I've also seen my coolant levels fluctuate a tiny bit.

 

[Mompantero]

This is not normal, the coolant is leaking out somewhere. At 36k miles you're not likely to be covered by the warranty. According to the owner's manual you should take the car to the dealer to have it inspected and repaired. Not a good sign, goodness knows where the coolant is going but it can't be good for the car.

 

[drdiesel1]

I second keeping an eye on the levels, but advise against adding deionized water as it would dilute the fluid. The level definitely fluctuates as it circulates and is affected by temperature. I’ve seen it dip slightly below the line even when it was new.

That amount of deionized water won't make a difference, at all.

 

[drdiesel1]

Ditto. Also, on page 262 of my '19 Bolt manual it says:
"Hybrid Cooling System
Pressure Caps
The hybrid cooling system
reservoirs have tamper resistant
pressure caps. The coolant should
only be serviced by a qualified
technician."

Also page 261 says:
"It is not necessary to regularly
check coolant unless a leak is
suspected or an unusual noise is
heard. A coolant loss could indicate
a problem. Have it inspected and
repaired by your dealer"

I recall I've also seen my coolant levels fluctuate a tiny bit.

They have a simple metal tab to stop them from being opened by the less intelligent would-be cobblers. Simple flex it away from the cap and remove it. This is done to prevent someone from using tap water and adding minerals to the system.
He purchased a USED CAR. He has no history information.

Over reacting to a simple low recovery bottle level isn't the way to handle this. Add the water and monitor is the first thing to do. If it drops again, then you can consider it has a leak. My car had an air pocket in the system and I had to add to it after a few months of operation.

It's never dropped again. Mine was new and I know where the level was when I did the PDI before I took delivery.
I have proof and history info. HE does not! Always use the K.I.S.S. method

 

[Sean Nelson]

Over reacting to a simple low recovery bottle level isn't the way to handle this. Add the water and monitor is the first thing to do. If it drops again, then you can consider it has a leak.

I agree, except that the OP checked the levels when he bought the car and then checked them again after he drove it 180 miles back home and he had lost an inch of fluid. That's cause for concern, particularly when it took the level down below the "minimum" line. I watch the reservoir he's talking about closely because when my car was delivered new the level of that fluid was right at the "minimum" mark. But the level on that one or the others has never changed on mine.

 

[GJETSON]

They have a simple metal tab to stop them from being opened by the less intelligent would-be cobblers. Simple flex it away from the cap and remove it.

It is simpler than that. All three reservoirs are the same. They have an overflow spout on the side. When the cap is tightened enough to hear a click, the opening on the outer part of the cap is just CW from the spout. If you rotate the outer cap CCW until it is on the other side of the spout, you can see the opening on the inner cap. Put a key, or similar into the hole to lock the two cap pieces together, and you can unscrew the cap easily. It has a 1/4" long, fine thread, and an O-ring seal, so be patient. It takes maybe three turns to come off. Screwing it back on doesn't require anything as a tool. There is a racket mechanism inside the cap. Tighten it until you hear a single click, and the opening will be back where it started, just below the spout.

 

[GJETSON]

If this is the case, would it be covered by the warranty?

I am sure it would be.

From the service manual:

 

[laurasheaclark]

I recently had one of my 2017 Bolt's battery modules replaced, and when I drove away from the dealer I got a service engine light that turned out to be low coolant. They filled it Thursday, and it showed low again today, Saturday. They filled it again today. I was told that they have to flush and refill the coolant when they replace a battery module, but shouldn't they test drive it or something to verify it's really full??

 

[Sean Nelson]

I was told that they have to flush and refill the coolant when they replace a battery module, but shouldn't they test drive it or something to verify it's really full??

I wouldn't think they'd need to if they did the job properly. Unless the battery replacement procedure that they follow specifically says "flush and test drive to verify proper operation".

 

[laurasheaclark]

I wouldn't think they'd need to if they did the job properly. Unless the battery replacement procedure that they follow specifically says "flush and test drive to verify proper operation".

I don’t really know. The tech said it was part of the process.

 

[GJETSON]

I don’t really know. The tech said it was part of the process.

Modern coolant systems run up and down hill, and have all sorts of drain trap-like bends. Normally they pull a vacuum on the system when they fill it. There should be no need for topping up, if they did that. Prof. Weber shows how it is done at 27 minutes in.