[vickster]

My Car Details

Model - XUV400EV ELPRO 39.4Kw
Year - 2024 April
Kms - 3200 Approx

I recently experienced an incident with my XUV400 car that left me a bit shaken. I had parked my car overnight out on my driveway after a drive in the evening. The next morning , our driver noticed smoke coming out from under the bonnet. He said it was intermittent and seemed to reduce a bit occasionally. But when it continued, I knew something was wrong.

I quickly got hold of a fire extinguisher that I had nearby and opened the Bonnet. I found that one of the coolant tanks was spewing hot coolant which was probably causing the smoke to spew out. I sprayed a bit of the extinguisher to put out the smoke. When I thought it was almost under control, a module (that the dealer later said was the VCU) also began emitting smoke from one of the connectors.

I immediately called the dealer's number to get some guidance on how to handle the situation. They advised me to call the fire department. By this time, a small crowd had gathered, and someone among them suggested removing the low-voltage battery terminal which we did. I presume this reduced the burning to an extent, preventing further damage. The fire department and Mahindra breakdown team arrived soon after by which time it was under control. Later in the evening, my car was towed to the dealer service center for further inspection and repairs where a team from Mahindra HQ is looking at it and doing some tests. Mahindra representative has informed that they do not have any reported cases such as this India wide and this is the first case. They have also said there have been instances of fire on the XUV400 reported at all.

I am writing this to know if any of the existing XUV400 owners have faced similar or fire related issues on this car model.

[KeepItSimple]

This is a most unfortunate incident and glad that no one was injured.

What was the ambient temperature when this happened? What is your car color?

Please update on the analysis of the incident by the service team and mahindra.

Best wishes.

[rving]

Nothing even remotely of this sort with our vehicle. Would like to know what Mahindra has to say about this.

[vickster]

Originally Posted by KeepItSimple

This is a most unfortunate incident and glad that no one was injured.

What was the ambient temperature when this happened? What is your car color?
.

Yes, thankfully it didn't happen while running. Car is White and outside temperature must have been under 30 degrees.

Originally Posted by rving

Nothing even remotely of this sort with our vehicle. Would like to know what Mahindra has to say about this.

Good to know. Mahindra has been very supportive but yet to make a diagnosis on the cause. Car is still in the workshop.

[KeepItSimple]

Please update when ever possible.

Thank you.

[Jeroen]

Originally Posted by vickster

. The next morning , our driver noticed smoke coming out from under the bonnet. He said it was intermittent and seemed to reduce a bit occasionally. But when it continued, I knew something was wrong..

I am not sure what to make of this? It suggests it went on for some time? Went from intermittent to continuous?

Any smoke coming from underneath the bonnet means you need to stop and investigate.

Coolant spewing out usually means some sort of problem in the cooling system. Coolant spewing can cause further problems if it spews onto electrical components and or connections. (It can cause a short)

It seems it might not have been smoke, but vapour? Cooling system problems on such an almost brand new car is extremely rare.

Good luck, let us know what they find.
Jeroen

[vickster]

Originally Posted by Jeroen

I am not sure what to make of this? It suggests it went on for some time? Went from intermittent to continuous?

Any smoke coming from underneath the bonnet means you need to stop and investigate.

Coolant spewing out usually means some sort of problem in the cooling system. Coolant spewing can cause further problems if it spews onto electrical components and or connections. (It can cause a short)

It seems it might not have been smoke, but vapour? Cooling system problems on such an almost brand new car is extremely rare.

Yes, the smoke from the coolant tank could have been vapour from the hot coolant but the second time from the electrical point, it was certainly smoke from something burning. The car was in parked condition when all of this happened and I hadn't moved it all that day.

Mahindra team has suggested that it was a leak from the Coolant tank that cools the Cabin heater. There are 2-3 coolant reservoirs in the XUV400 and this coolant tank apparently is independent from the main battery coolant. They also mentioned that the cabin heater could be faulty which may have resulted in the problem. Still, no concrete findings yet. They said that component is a Korean part and it needs to be inspected by the vendor until anything can be said. Car is still in the workshop.

[Jeroen]

Originally Posted by vickster

They also mentioned that the cabin heater could be faulty which may have resulted in the problem. Still, no concrete findings yet. They said that component is a Korean part and it needs to be inspected by the vendor until anything can be said. Car is still in the workshop.

If they know on a component level what is needed, they also know what failed!

Jeroen

[ghodlur]

Originally Posted by vickster

I found that one of the coolant tanks was spewing hot coolant which was probably causing the smoke to spew out. I sprayed a bit of the extinguisher to put out the smoke

I found this a bit puzzling, why will the coolant spew hot? Does this mean the engine was running coz the coolant gets hot only when the engine is running. What is the coolant in a EV used for? Plus was there any visible source of leak say a crack or something in the coolant fluid body?

I am following this thread very closely as one of my cousins has a Mahindra EV and will be updating him accordingly.

[electric_eel]

Originally Posted by ghodlur

I found this a bit puzzling, why will the coolant spew hot? Does this mean the engine was running coz the coolant gets hot only when the engine is running. What is the coolant in a EV used for? Plus was there any visible source of leak say a crack or something in the coolant fluid body?

The coolant is used to cool the battery pack and the inverter unit. If the car is being charged even if it is on a 16 amp plug, the cooling system can get activated particularly when the ambient temperature is high (say uncovered parking in the sun).

[EV Fan]

Originally Posted by vickster

Good to know. Mahindra has been very supportive but yet to make a diagnosis on the cause. Car is still in the workshop.

A lot of us would be following this thread.
Hoping that Mahindra does a thorough diagnosis and tests the vehicle, post the fix. Especially since it is a fire risk.

Originally Posted by Jeroen

If they know on a component level what is needed, they also know what failed!

Jeroen

True. I think they might be doing additional checks, as the failure could have been caused by another related unit.
Personal experience with symptomatic fixes (3 rounds) made me realize it the hard way.

Originally Posted by electric_eel

The coolant is used to cool the battery pack and the inverter unit. If the car is being charged even if it is on a 16 amp plug, the cooling system can get activated particularly when the ambient temperature is high (say uncovered parking in the sun).

I think that the XUV 400 has a bit aggressive cooling. It's active cooling can come online at the slightest prospect of heating (probably could also be the reason of its high consumption figures).

[vickster]

True, the XUV400's cooling system works slightly different from the Nexon EV from my experience. The Fan goes on and off during charging and also in idle switched off condition. Mahindra says this is done to cool the batteries. It probably has to do with the NMC batteries that this car has. The Nexon does this switch on and off too but less often.

There was no visible damage to the coolant tanks and I don't understand how the coolant tank leaking should affect the cabin heater. I am told that the Cabin heater's function is to heat the cabin if required. In ICE cars the residual heat from the engine is used for this purpose.

It is most likely some sort of electrical issue with the main High Voltage battery though Mahindra is insisting that it is not the case. Attaching a picture of the component that failed - B as shown in the manual. The leaked coolant tank is also visible in the back.

[BlueGod]

Hi

Did you get any updates from Mahindra?

[electric_eel]

Originally Posted by vickster

My Car Details

Model - XUV400EV ELPRO 39.4Kw
Year - 2024 April
Kms - 3200 Approx

I quickly got hold of a fire extinguisher that I had nearby and opened the Bonnet. I found that one of the coolant tanks was spewing hot coolant which was probably causing the smoke to spew out. I sprayed a bit of the extinguisher to put out the smoke. When I thought it was almost under control, a module (that the dealer later said was the VCU) also began emitting smoke from one of the connectors.

I would be very keen to know what happened. I had a similar situation not with and EV but with my Maruti Zen petrol. Thanks to the lack of any kind of engine noise insulation, I noticed a change in engine note (on a highway drive) and immediately brought the car to the service lane, opened the hood and found out hot coolant boiling out. A few of the truck drivers present there, helped me get a temporary fix and I drove it to a independent mechanic near by who did a wonderful job of fixing the pipe. He is some one who works/worked in a ship and these simple leaks and fixes were just routine for him.

My understanding of that incident is thus (correct me if I am wrong): If there is not enough coolant say due to a leak, the remaining coolant gets too hot before it can cool itself at the heat exchange/radiator. In the worst case, this can lead to boiling of the coolant which comes out as smoke. Once the coolant starts boiling it is a vicious cycle as there is further coolant loss due to evaporation as well as worsening of the leak due to increase in pressure.

There could be an alternate reason for coolant loss/boiling; cabin heating could be using the hot coolant for heating the cabin through a heat exchange of sort as explained in the video below

https://youtu.be/Dujr3DRkpDU?si=E7212D0_5_z8Rrdb

If there is a fault in the heat exchange, the coolant could get too hot and boil. That could explain why Mahindra is looking into the cabin heating system as well. However I do not understand why a stationary car would have this problem. The cabin heating should not even get activated. Or may be some fault in the system is diverting the coolant to cabin heating unit when it is not supposed to and thus not getting cooled enough.

Disclaimer: I am not an expert in any of this. It is merely an educated guess and I would like someone more knowledgeable to correct me.

[vickster]

Originally Posted by BlueGod

Hi

Did you get any updates from Mahindra?

Yes, they are in touch with me but the car is still in the workshop. No solutions yet.

Originally Posted by electric_eel

I would be very keen to know what happened. I had a similar situation not with and EV but with my Maruti Zen petrol.

The coolant level wasn't low. It still beats me on how coolant in a stationary car can boil over. I am drawing comparisons to recent incidents in Korea with the Mercedes EQE. The EQE was parked and stationary too when smoke started bellowing out of the bonnet which progressed into a full on fire. It was the same pattern here too. A common element between these cars could be the Farasis NMC battery pack. Thankfully, this happened during the day and we caught it in time.

But I still cannot comprehend how the cabin heater and it's dedicated coolant tank has anything to do it. The heater has an HV (Orange Cables) line going in as evident in the the diagram I posted earlier. Mahindra denies that it's a HV battery issue. But from what I witnessed, it was clearly an electrical issue that could have progressed.

The cooling system on the XUV works differently from the Nexon. For instance, when you start the car, there is a strange sound of flowing water from the glove box. This apparently is the coolant circulating. With the Nexon, I didn't have this. But somethings are common such as the Radiator fan switching on and off while charging.