Car cooling down at stop light in -6C/22F. Car dealership says they can have a look in two weeks. Until then should I go for a coolant flush in Jiff Lube?

General Hyundai Forum
1

Elantra 2023, 1.5 years old, 29k miles.
Coolant looks fine, pinkish in color, almost full when cold.
I opened the radiator cap, and the coolant is fine there too.
Smells a little burnt if you sniff the coolant but the color is pinkish.

Only cools down at a traffic stop, not if you keep RPM above 2-ish.

I best guess someone topped it up with water or something during the last oil change; it seems like it was topped up from the last oil change at the dealership as they left the cap open. That is not fit for an environment like this, or I don’t know.

2

If the car is under warranty, don’t touch anything until the dealership does. They might blame Jiffy Lube and refuse warranty work.

3

Why would you take it anywhere other than a dealer when you have a warranty? Why would you change the coolant on a 2023 vehicle? You should leave the service to those who know what they are doing. Take it to the dealer and nowhere else. If you take it to Jiff Lube, you will need a new car.

4

The temperature gauge also drops down and the heater stops working, even after driving approximately 50 miles.

5

What does the coolant look like? What color is it and is it low? Does your radiator cap (when cool, of course) have the forbidden chocolate milk on it?

6

Zack said:
What does the coolant look like? What color is it and is it low? Does your radiator cap (when cool, of course) have the forbidden chocolate milk on it?

Coolant looks normal and is almost full.

7

Just spitballing, warm your car up and then check your radiator hoses. Maybe they need to be replaced. I’ve had a buddy whose hoses were collapsing and stopping the flow of antifreeze at idle.

Squeeze them and see how soft they are. They should be a bit stiff. Naturally, be careful as they are likely hot.

8

I love it when people post these questions and the car is either 10 years old or 1 year old. Which would have two completely different issues. lol

What year and model? Miles?

Is your coolant low?

Continuing to drive your car without figuring out the issue could destroy your engine’s head gasket.

I’m going to put on my Carnac the Magnificent hat and mind-read what is in the envelope I have held to my forehead. :wink:

The car is over 5 years old, closer to 10 and they never checked the coolant.

My prediction is a) the thermostat is bad, or there is a leak, hopefully not the heater core.
b) It’s both, hopefully, it’s a radiator or hose leak and not the heater core.

Every time I’ve had a bad thermostat, it would run cool when stopped. This last time I noticed it running cold on the way to pick up meds for my cat from the after-hours drop box. Thought, hmm, I need to get that taken care of; I will look into it tomorrow since it was 7 PM.

I drove with my eye on the temp gauge, got exactly to the middle of nowhere, temp started to climb; fortunately, I was at the vet. Pulled into the parking lot, the radiator exploded and I had to call a tow. Thankfully my head gasket survived. The first time I had that happen I learned the expensive way and blew the head gasket on my Nissan.

If it’s new, top off the coolant, drive it a couple of miles, and check it. If it’s low, call the dealer and have it towed. If the temp rises to the middle of the gauge, park and call the dealer to have it towed.

In either scenario, watch the temp gauge like a hawk. Unless it’s a hybrid, it’s not normal and needs to be looked at. If it’s a hybrid, it’s a hybrid thing.

9

@Callen
Now that the OP has updated their original post to include some helpful info. lol

At one time, the thermostats for the 2023 Elantras were on backorder. Probably means there was a production issue with them at some point.

Probably your thermostat. Also, it’s concerning that it was topped off with water and not pink coolant if you are in a cold climate. Did the dealer do this?

Either way, you should probably test your coolant if it was parked outside. It’s a vibrant color normally, so if it’s not vibrant, it’s been diluted. Note: I think green coolant is compatible. If you weren’t at the dealer and they put in green coolant, that would affect the color but it would make it brownish, so likely not.

10

My guess is your thermostat is stuck open or maybe your electric fan, depending on the setup, is not shutting off.

11

Evans said:
My guess is your thermostat is stuck open or maybe your electric fan, depending on the setup, is not shutting off.

Most likely, but I didn’t see the fan running. Highly likely the thermostat is stuck open.

12

What car? I had a Kia Forte 2.0 engine that just would cool down if it was cold out and the heater was on. I think the engines just run cold like that.

13

Adam said:
What car? I had a Kia Forte 2.0 engine that just would cool down if it was cold out and the heater was on. I think the engines just run cold like that.

You have the same issue; if the engine runs cold, the car increases the RPM.