2025 Hybrid Coolant Leak

[25 Mavrick]

Frequent reader first time poster.

I have a slight coolant leak somewhere in the main cooling system (not hybrid system) in my 2025 hybrid and I don't see any signs of leakage anywhere. It drops from the full mark to the fill mark in around 4000 miles. Has anybody had a similar issue and where was it leaking from?

Thanks

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[JMJB]

Sounds like a trip to the dealer is in order , have them document it , and top it off , then monitor it ....warranty .

 

[OleFordGuy]

There have been other threads on the issue in the past. Take a look at the "similar threads" at the bottom of the page, also search coolant leak, etc

 

[25 Mavrick]

Thanks for the replies. I did a search and didn't see anything in the first 7 pages, I checked the similar threads and see the heat exchanger for the hybrid battery could be it. I checked mine and it appears bone dry. I will fill and keep an eye on the heat exchanger.

Thanks all

 

[icegradner]

Thanks for the replies. I did a search and didn't see anything in the first 7 pages, I checked the similar threads and see the heat exchanger for the hybrid battery could be it. I checked mine and it appears bone dry. I will fill and keep an eye on the heat exchanger.

Thanks all

Is this right after driving or after it's been sitting for 3+ hours? Coolant level should only be checked when the vehicle has been off and fully cooled down.

 

[SafetyGuy]

Thanks for the replies. I did a search and didn't see anything in the first 7 pages, I checked the similar threads and see the heat exchanger for the hybrid battery could be it. I checked mine and it appears bone dry. I will fill and keep an eye on the heat exchanger.

Thanks all

Good evening

I have to support @JMJB and the suggestion to see your dealer so they maybe can do system pressure test, and whatever else they can do to find a coolant leak...and it's now on your record for warranty purposes.

If no leak found, then it also could be internal.
.any smell et the exhaust of coolant? That would help but if it is a slow leak inside the engine it would be hard to detect.

Up to you about how bad it is, but myself, I am not a patient person when a problem shows it's face...and especially if I have a warranty to fall back on.

I hope you can find out where the leak is and let us know!

Andy

 

[Cancunbadlands]

I'm looking forward to see if you can find out where the leak is and let us know please

 

[First Sergeant]

Probably no issue, but just for grins, I would pull oil dipstick and look for anything unusual, like a "milkshake" color. You never know. 1968 Ford Falcon station wagon, 6 cyl. Blown head gasket, drove it for 8 months, sold it to buddy after I was transferred. Told him about it, he drove it another 4 months till it blew. We just changed oil about every 3 weeks, kept water topped off and drove EASILY. This was when I was a Private U.S. Army 1973. We were so poor told people we couldn't afford the extra 2 letters in poor. We was "PO"! Haha. Hope you find out what the issue is, probably nothing big.

 

[deanobc]

Frequent reader first time poster.

I have a slight coolant leak somewhere in the main cooling system (not hybrid system) in my 2025 hybrid and I don't see any signs of leakage anywhere. It drops from the full mark to the fill mark in around 4000 miles. Has anybody had a similar issue and where was it leaking from?

Thanks

If you are not seeing an actual leak on the ground, how do you know there is a leak? My reservoir, when first parked is normal but will drop as the vehicle cools and is parked for long periods. Unless you have an eyeball on coolant on the ground, why do you think it's leaking?

 

[OleFordGuy]

IMO it's normal for the coolant level to change due to the expansion of the fluid when it's hot. Always check the fluid level after its had time to cool off. Once cooled off the level should be midway between the Min/Max marks on the reservoir. Once you have it to the correct level, check it regularly after cooling off, if it consistently or frequently falls below the Min mark, I would have it checked for leaks. That's my 2 cents

 

[25 Mavrick]

Thanks for all the replies. The coolant reservoir drops from the full mark to the fill mark in about 4000 K miles. I check in morning when cold. No milkshake in the oil cap. I drive long drives every day. I have a 2 hour drive today and will check heat exchanger immediately after. I will keep you guys posted.

 

[MaverickDragon]

Did the fluid level drop just once after 4000 miles?
If so, the fluid could have been displaced by an air bubble.
AFAIK, the engine cooling system isn't sealed, so some loss happens through evaporation.
Fill it when COLD and monitor the level.
You may be chasing a non problem, but if the level continues to drop after it's filled and when checked under the same conditions, you have a warranty... Go see the dealer.

 

[bgctcowboy628]

Frequent reader first time poster.

I have a slight coolant leak somewhere in the main cooling system (not hybrid system) in my 2025 hybrid and I don't see any signs of leakage anywhere. It drops from the full mark to the fill mark in around 4000 miles. Has anybody had a similar issue and where was it leaking from?

Thanks

Had a similar issue with a Chevy s-10 once the coolant level kept going down and the oil level kept going up. It was a head gasket. But then again, it was a chevy

 

[BlueSpec1]

My front tank is down in level a bit since I got it Oct 2023.
The driveway slopes, so photos are not when the truck level.

10-2023

12-2024

01-2026

 

[Ranko Kohime]

I’ll add my report now that it seems my “leak“ has stopped.

2025 hybrid FWD, started losing coolant about 30,000 miles in, reservoir dropped all the way to the lower hose, I filled back up to the Max line, then it dropped down to the Min line again. from 50,000 miles now up to 61,000, it hasn’t lost any more coolant, so my theory is it just took that long to bleed some air out of the system.

this is a truck heavily used for towing, and a pressure test done somewhere in the 40,000 range did not detect any leaks, nor do my oil samples report any sodium or potassium in the engine oil.

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