Q: Over heating but water is flowing through radiator

asked by on October 02, 2016

My car is over heating, I can drive about 20 mins before it starts to over heat. There's no water leakage the radiator seems to be having water flow through, my water resovior seems to be sucking and pushing water into it. I just done see what else it could be. Not sure is its the temp gauage or switch or just need a new radiator

My car has 279000 miles.
My car has a manual transmission.

Hi there, there are a number of things that can cause a vehicle to overheat. The water flowing through the radiator can be a little misleading. Here is a list of possible causes:

These can cause overheating and as you pointed out, the gauge or the temperature sensor could be reading incorrect. An infrared temperature gun is the best way to determine if your car is actually overheating. These can be purchased at your local auto parts store. An infrared gun is often around $50 and isn’t always necessary, but it can help clarify if your motor is actually overheating.

Checking the coolant level should be done with the car cold by removing the radiator cap and making sure the radiator is completely full. Then top of the coolant jug if it is low.

Testing the thermostat is fairly simple. Begin with a cold motor, start the car and wait for the upper radiator hose to become hot to the touch. If your temperature gauge is showing your car is overheating but the upper radiator hose isn’t to hot to touch, you need a thermostat.

Radiators can clog internally and externally. External clogged radiators will have road debris stuck in their cooling fins. This you can see by simply visually inspecting the radiator from the front of the car. You can clean it with a water hose usually. Sometimes you will need to use a soft brush. Be sure not to bend the cooling fins. This will also result in overheating. Internal clogging requires the car to be completely warm with the thermostat open. Drive the car around the block and come to a stop in your driveway, turn the car off, open the hood and feel the radiator with your hand. The top should be to hot to touch and the bottom should be cooler. You are checking for cold spots that will be cold to the touch. If you find cold spots, you need a new radiator.

The best way to check for coolant flow is to remove a heater hose, then start the car. If the water pump is working, coolant should shoot out of the hose. Often choosing what hose to remove for this test can be challenging. So if the first one you remove doesn’t yield any flow, try another, but don’t remove the radiator hoses. If you don’t get flow, I would suspect the water pump impeller has problems.

Checking for a blown head gasket can be a challenge if you have never done it. The ideal method is using a tool called five gas analyzer. The next method is what is called a block tester system. The gas analyzer is a very expensive machine. The block tester can be purchased at your local auto parts store. Simply follow the instructions. The challenge of testing for a blown head gasket is because it happens in degrees. It can be really bad, it can happen only at certain times and it can happen randomly and inconsistently. This is where experience comes into play.

If you should need help with determining if you have a head gasket problem, I recommend the having a certified technician from YourMechanic assist with diagnosis of the overheating issue in order to have this properly corrected.

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

What others are asking

Shaking at high and low speeds.

Hi Javier. Thanks for contacting us tonight. What you're describing seems to indicate an issue with your wheel bearings. Typically if you hear a grinding or high pitched squealing noise when you turn to one side and at high and...

2001 Monte Carlo 3.4L overheating. Does not blow warm air.

Hello. We will be happy to assist you. After the radiator was replaced the coolant system should have been pressure tested to make sure there are no more leaks present. If there are no more leaks present the coolant system...

I overfilled my engine with engine oil

If you overfilled the engine oil you may have got oil into the tops of the pistons and fouled the spark plugs. Once you adjusted oil level and start the car again it will blow smoke for a while until...

Radiator takes water out in the top radiator hose is bone dry and water is not running through it

Hey there, thanks for writing in about your 2004 Buick Rendezvous. When the engine is cold, the thermostat will remain closed and keep coolant circulating through the engine to be warmed up faster. Once the coolant inside reaches operating temperature,...

How do you open and close the power windows?

Your car is equipped with power windows. They’re certainly more convenient than manual windows, but there are a few things you’ll need to know about operating the system. Here are the important details: The ignition must be on to...

Hit a Curb 2016 Honda Accord

Hello - this task is best handled by a collision repair estimator at a reputable paint and body shop. S/he is trained to evaluate visible and not-so-visible damage, and the costs to repair. Contact a reputable paint and body shop...

How do you adjust the sound on the audio system?

Your Accord’s audio system lets you adjust the level of treble, bass, mid-range and other sounds through the interface. All you need to do to customize the sound of your audio system is follow these few brief steps: Press...

Valve adjustment on a 2010 Honda Odyssey

Yes it is bad if you don't do it. You'd want to have it checked at least. If they are not more than 4,000 of an inch off, you can leave them alone and drive it. But on Hondas, they...

My car is jerking while driving, and when sitting idle

You will want to have the fault codes in the transmission and engine computer read out. Based on previous transmission concerns, the operation of the CVT transmission is highly dependent on how well the engine is running. Misfires, valves out...

Related articles

The Top 5 Selling Cars in Florida in 2012
Florida Florida offers great weather year round, and the fact that snow and ice never factor into the equation means drivers don’t have to focus on the overall vehicle handling as they do in other states. The best selling cars...
The Top 5 Selling Cars in Kansas in 2012
Kansas Kansas sees a varied climate with all four seasons, which means drivers in the area choose a variety of vehicles. In years past, some of the front-runners have included the Ford F-150, Buick and Toyota Camry. 2012’s top five...
Symptoms of a Bad or Failing Cylinder Head Temperature Sensor
Common signs include long cranking time, engine performance issues, and the Check Engine Light coming on.