Coolant smell from air vents

van604

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Ok, there are enough of us here that are experiencing the same issue (coolant smell in the car, possibly from heater core or A/C drain plug issue) that I think this is a common issue. MY CAR has the smell and its getting worse and worse.
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idragmazda

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Hey guys, I’ve got a 2018 type R and I’m noticing same issue with the sweet coolant smell

I think it usually happens When the selector is on floor heat or floor + defrost too.

I’ve got about 12k miles on the car and I smell it ocassipnalt but not all the time. It’s dricing me nuts!

Sounds like a common issue with no fix?
 

Roadcone

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I'm having this EXACT SAME ISSUE. 300 miles on the car now and it's driving me nuts
 

idragmazda

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I had the dealership change the coolant, check for leaks, and also change the cabin filter.

They said they didn't find any leaks and I still have the smell occasionally. Meh another quirk of the car I guess.
 

Gotch

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Which way is the wind blowing when you smell it? If it is from the back of the car to the front, it is exhaust you are smelling. I park my car with prevailing wind to the back and have that “coolant” smell when it is windy.
 


idragmazda

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Which way is the wind blowing when you smell it? If it is from the back of the car to the front, it is exhaust you are smelling. I park my car with prevailing wind to the back and have that “coolant” smell when it is windy.
It’s usually when driving forward at speed with windows cracked. Creates a vacuum effect inside the cabin and the smell comes through vents.
 

SCOPESYS

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Hey guys, I’ve got a 2018 type R and I’m noticing same issue with the sweet coolant smell

I think it usually happens When the selector is on floor heat or floor + defrost too.

I’ve got about 12k miles on the car and I smell it occasionally but not all the time. It’s driving me nuts!

Sounds like a common issue with no fix?
I look at it like this.

COOLANT should be in a closed system. There should be no coolant vapor escaping anywhere, to get into the passenger compartment.

Assuming these is no coolant leak, the only place the coolant liquid is exposed to the outside air, is the overflow from the coolant reservoir. So coolant vapor could be leaking from there, especially if HOT coolant is passing back to that reservoir.

There should be an overflow pipe, that travels from the Reservoir, down deep towards the ground in the engine compartment, so any Coolant overflow (or Vapor) gets discharged down towards the road, and not into the engine compartment.
Make surer Coolant reservoir fill cap is on secure and seating & sealing correctly

Should be much more noticeable under the hood.

But then theses should be no airflow from vapors developed under the hood, back into the passenger compartment (Ideally).

You can test for that by spraying something heavily scented into the engine compartment -- (like Air Freshener) maybe onto the heat baffle under the hood, and then "smelling" if it leaks into the Passenger Compartment, under different conditions of A/C, Heater, and driving. (Especially with air on Recirculate or not).

Gas fumes in the Passenger compartment are especially undesirable, if nothing else, from a health (Cancer) point of view, as well as impairing your driving as the gas fumes affect your breathing and make you feel sick & dizzy.

When the DEALER says "Its normal", that is BS !!! Do not accept that excuse to get rid of your concerns.
 

BallisticSquid

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I have noticed that when I use the windshield washer, I will get a slight smell of coolant in the car. The washer fluid seems to have a smell similar to coolant...to me anyway.
 

idragmazda

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I have noticed that when I use the windshield washer, I will get a slight smell of coolant in the car. The washer fluid seems to have a smell similar to coolant...to me anyway.
Hm. I'll have to check this today!
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