Can car be low on coolant and temp gauge still be fine?

Looks like I got a leek I gotta get checked out since right now it way to cold to do the work myself but I filled the rad and tank back up about 2 days ago and I just checked both and it’s missing a good amount. A 15 min ride I took to the store today and the temp gauge acted normal.

My question is, like, is this possible? Like I would have figured it would create air pockets that get hot and make my temp gauge spike?

I’m making sure it doesn’t get to high so I don’t damage the engine and fill it up until I make it to the shop.

Yeah it doesn’t necessarily have to be full to get enough cooling to keep the engine from over-heating, especially if it is cold out. And a short drive may not be enough to fully warm it up. The first indication of low coolant is usually the heater not putting heat out. Just keep filling it up and get the leak fixed.


That’s the thing to. The heat is really toasty warm to.

I’ll make sure to fill it up when I leave tomorrow.

Temp gauge is connected to some sensor, which in some cars can happen to be installed high in the system, where an air pocket can make the sensor not to read the temperature correctly.

What can happen: your gauge can read normal up to the point where steam starts shooting from the engine.

You did not tell what car you drive, so generic answer here.

If coolant gets low as fast as you describe, it must be a big leak, needs to be taken care of ASAP.

Yup. You just proved it.
The trick now is to find out where the fluid went.
Do you have any other symptoms? Any puddles in the garage?

My suggestion is to have the system pressure tested looking for a leak. If none is found, test the coolant for any presence of hydrocarbons. If you find some, you have a breech in your headgasket.

If you don’t find any, I’d do the next two things:

  1. perform a leakdown tests on the cylinders.

  2. add a UV sensitive dye to the coolant, run the engine, and look for the leak path residue to light up under the UV. A kit can be purchased cheaply that includes both the dye and the UV light.

  3. if that doesn’t yield results, you could be dealing with an intake manifold gasket leak, the coolant being ingested into the engine. You didn’t mention the year, make, or model of the car and its engine. That information would help.

When I went to the shop to change my axle they said they saw some dried off coolant top of transmission. So I think I may have a leak.

Usually you don’t get an air pocket unless you just run it completely dry or you perform cooling system repair like changing a radiator or water pump

Keep in mind that depending on the type of car you own, that temp gauge may not be attached to ANYthing but software.

Yeah, software. Some cars “estimate” the coolant temp or oil temp of the engine based on data on the OBD2 communication network.

What really?

The car is 2006 Hyundai Tucson.

I refilled the coolant and turns out it was only missing like about 7 ounces.

I don’t know about the Veloster but my 2013 Mustang has a “software” coolant temp gauge.

The concern about the 7 ounces is just how it is leaving the engine. Look for green trails. Hopefully you’ll find one or 2. If not, that coolant is going out the exhaust. And that means manifold or head gaskets or far worse, a cracked block or head.

Oil seems clean. When the shop changed my axle they said they saw some dried on top of transmission.

Also I forgot to mention though expansion tank was also pretty low, more than 7 ounce I had to put in there.

A failing head gasket can allow the coolant into the combustion chamber where is turns to steam and is exhausted. Same for cracks in the block and head. Same for manifold gaskets on some engines. It doesn’t always have to “milky-up” the oil.

I lost a head gasket on a 350 Chevy. It kept losing coolant but the oil looked OK and no puddles. The exhaust smelled “sweet” and was overly wet when warmed up. The gasket failed between a coolant passage and the combustion chamber. That piston was super clean, though!

More often than not the breech in the headgasket will be from the combustion chamber to the water jacket and oil won’t be affected. The condition of he oil is not a good indicator of the condition of a headgasket.