I’ve got a 2023 Camry LE (4-cylinder) that I bought new, and I’ve noticed something odd. When it’s cold outside and I’m idling in stop-and-go traffic or at a light with the heat on, the temp gauge drops slightly from its normal halfway point. The heat inside the car still works fine, and the coolant level looks good. Friends with similar cars and some forum posts say it’s normal, but other sources mention issues like a bad coolant bypass valve or sensors. Has anyone else experienced this? Is it something to worry about, or am I overthinking?
The heater warms the interior but also cools the engine. Pretty normal in cold weather.
Think of the heater like another radiator for the engine. It pulls heat from the coolant to warm the cabin. If your temp goes back up when the heater is off, it’s nothing to worry about. Also, you’d see a check engine light if there was a bypass valve issue.
It’s likely just a cold day affecting the engine temp. How long was the car running when you noticed this?
Whit said:
It’s likely just a cold day affecting the engine temp. How long was the car running when you noticed this?
I’d driven about 12 miles on the highway before I noticed it. The temp gauge was steady at the halfway point while driving but started dropping when I slowed down and stopped.
@Starry
Sounds like a mix of cold weather and the heater cooling the engine at idle. Nothing unusual.
@Starry
Modern cars are super efficient, especially in cold weather. At idle, the engine produces less heat, and if the fans are running or the heater is on, it can cool down more. Totally normal.
Modern engines use so little fuel at idle that they can’t always maintain temperature in the cold. My Yaris does the same thing if it’s super cold out and I have the heater cranked up.
If it’s a hybrid, that’s completely normal. If it’s gas-only, it might be worth looking into. My hybrids tend to fluctuate more than my gas engines.
Bradas said:
If it’s a hybrid, that’s completely normal. If it’s gas-only, it might be worth looking into. My hybrids tend to fluctuate more than my gas engines.
It’s gas—it has an RPM gauge. Hybrids don’t usually have those.
@Frey
Actually, some hybrids do. My sister’s Corolla Cross Hybrid has one.
Barrett said:
@Frey
Actually, some hybrids do. My sister’s Corolla Cross Hybrid has one.
Not on Camrys though. Do a bit more research before arguing.
Barrett said:
@Frey
Actually, some hybrids do. My sister’s Corolla Cross Hybrid has one.
For the record, my Camry Hybrid does have an RPM gauge. It’s not a hard rule.
How cold is it outside? Mine does this too when it’s below freezing, but it’s totally fine unless you get a check engine light.
If you don’t blast the heat, the temp gauge might stay steady. My old Corolla did this when it was super cold out, but it’s normal.
Alden said:
If you don’t blast the heat, the temp gauge might stay steady. My old Corolla did this when it was super cold out, but it’s normal.
Funny, my older Corolla never did this. Neither did my ‘91 Camry. I guess I’m still stuck in the past with cars lol.
@Starry
Older cars were a bit less efficient. My newer Corolla Hybrid does this all the time in winter because the engine doesn’t run constantly.
What really matters is the oil temperature, not so much the coolant temp. This kind of fluctuation is common, especially in hybrids or in stop-and-go traffic during cold weather.
If you’re worried, turn the fan down to low and see if the gauge rises. That usually helps.
Modern engines are designed to be super efficient, so this is perfectly normal, especially in cold weather. If your bypass valve was faulty, you’d get a warning light.