Q: Temperature gauge goes up and down

asked by on October 01, 2017

I was drag racing for a while, then when I parked my car, I noticed that boiling water was falling from the car, quickly had a look at the temperature gauge and I can see that it reached 3 quarters.

Then I took my car to the fuel station and I requested somebody to put water to the water container ( linked to the radiator) , then steam and pressure started to release, however when he opened it, water level was not low, it was above half the container.

I had a look under the hood and I can see that the fans are cooling very well.

Then I returned home and on the way, the heat gauge goes up and down. regardless of the situation. I tried the following scenarios:

  • Flooring the gas pedal
  • Stopping the car
  • putting the AC on
  • going fast
  • going slow They don't really affect the fuel gauge and it just keeps going up and down ( doesn't reach MAX though.. it reaches to 3 quarters only)

However, when I set the cruise control and go in a fixed speed, temp gauge stays low

Car is overheating Inspection $94.99 - $114.99 Get a Quote

You’re probably low on coolant. Filling the reservoir doesn’t really do the trick for filling the cooling system. There is probably air trapped in the cooling system that needs to be bled out. You may be able to do it yourself without extreme measures. Starting with a cold engine, start the car and set the climate control to max heat. Take off the radiator cap and fill the radiator, not just the reservoir. let the car idle with the radiator cap off , adding coolant as the level drops until the engine is fully warmed up and the heater is blowing hot. This might take as much as half an hour. Then put on the cap and see how it does. If this doesn’t work out, contact YourMechanic. They will send a technician to your home or office to check out your overheating problem and let you know what it will take to solve it.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Car jerks and stalls in First and Second gear
It is possible that the hydraulic system for your clutch pedal may be causing your problem. Depending on the mileage that is on your clutch, and how you drive, you may also be due to have the clutch replaced. Either...
Clutch pedal going soft after you bleed it. Has s new clutch and a auto shop says it's the master cylinder
Hello. If the clutch pedal is going soft even after it is bled, then that is an indicator that there is either a problem with the master cylinder (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-clutch-master-cylinder) or the slave cylinder (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-clutch-slave-cylinder). If the seals inside the master...
Service engine soon light keeps coming on
Hello. It is not normal for a fairly new car with low miles to have the Check Engine Light come on. However, that doesn’t mean that sensors won’t fail. There may also be sensors that are faulty, in addition to...
How would I know if it was my upper or lower oxygen sensor that has gone out?
Typically if an oxygen sensor is bad, the check engine light would come on and a fault code stored in the engine control unit. There are other ways a technician can verify if oxygen sensors (https://www.yourmechanic.com/services/oxygen-sensor-replacement) are performing as they...
Oil light goes off and on.
This light will usually come on when one of two things are happening. Either the motor is in fact low on oil or the oil pressure sending unit (https://www.yourmechanic.com/services/oil-pressure-sensor-replacement) is not working properly and may be producing a faulty reading....
Transmission fluid capacity Aisan TF 80 ?
Hi there - this transmission holds approximately 4 quarts of fluid (https://www.yourmechanic.com/article/how-long-does-transmission-fluid-last). However, it is impossible to change the fluid by simply draining the fluid - will only get a fraction of this amount. Fluid changes with a fluid change...
My car leaks under the dashboard when it rains or I go through a car wash near the brake & gas petal
Hi there. Water leaks can come from various sources: a clogged drain tube in the AC/Heater box can cause overflow through the heater vent, or faulty cowling can cause water ingress into the passenger compartment. Once the source is found,...
I want to buy a car but it has a blown head gasket, is it worth it.
A rough estimate to replace head gaskets would be in the $2800 to $3200 range for parts and labor depending on damage and parts needed.

Related articles

The Best Used Cars to Buy If You Like to Go Off-Roading
Your Your best bet for off-roading is a 4x4 SUV. Depending on the model that pleases you most, though, you might have to shop around a bit to find a good used one. That’s simply because off-roaders typically become very...
How to Replace a Cooling Fan Relay on Most Vehicles
Cooling fan relays fail when the radiator cooling fan no longer receives an electrical signal. A broken fan relay means the radiator cannot cool down.
Why Cooling System Repairs on a European Car Can Be Tricky
Repairing a cooling system, such as if there is a leak, can pose different obstacles. Many repairs may involve finding the radiator of the system.