Hyundai Santa Fe engine running hot.

Coolant temperature is the best measurement of engine temperature. If your gauge shows normal temperature and is accurate, your engine is not running too hot. Is your coolant at the proper level? If you get an air pocket i n the system, this can cause the gauge to read too low.

It is normal for everything in the engine compartment attached to the radia tor or engine to be too hot to touch. Is the battery in physical contact w ith the radiator? Even if not, it will get hot just from convection.

I don't trust the temp. gauge. About to weeks ago while on the road the top radiator hose developed a leak and there was no indication that anything was wrong until the engine started making a sound that sounded like little knocks and then it quit, the water temperature gauge showed that the temp. was normal. How can I check the temp. gauge or the sender? How can I check the water bump? How does the thermostat in the radiator cap work? The rubber seal under this cap is torn, can that cause a problem? Thanks

In the case of the hose leak, the gauge may have not read hot because there was then insufficient coolant in contact with the sensor. Unfortunately, running hot can damage the sensor. I haven't seen this much on Hyundais, b ut it does happen. And worse, considering your description, the engine may be damaged from overheating.

You can check the sensor itself by comparing its resistance to the specifie d resistance at the temperature of the coolant. You can also attach a scan tool and read the coolant temperature from the engine control module (whic h uses a separate sensor element) and compare it to the gauge reading. You 'll probably need to take the car to a shop to accomplish this method.

Presuming they are both functioning, the easiest way to check the water pum p and thermostat is to check for coolant flow. Start the engine cold with the heater and a/c off. The radiator hoses will be cold. As the engine wa rms up, the upper radiator hose should get hot first. As it reaches proper operating temperature, the thermostat will open, allowing coolant flow. A t that time the lower radiator hose should be as hot as the upper radiator hose. The fans should start running to manage the coolant temperature. As long as the fans continue to cycle on and off (slow speed, not high) while the vehicle is idling, it's a reasonable assumption that the basics of the cooling system (thermostat, water pump, fans) are working properly. The f ans coming on indicate the ECM is attempting to keep the coolant temperatur e low enough, and the fans turning off indicates that the coolant did indee d cool down a bit.

There is no thermostat in the radiator cap. It releases coolant via a pres sure valve. Most are around 1 bar. It allows coolant back in from the res ervoir via a valve that opens when a vacuum is created in the radiator.

The torn gasket on the cap can cause a leak. Even if it's not leaking now, I'd replace the cap. It's too cheap to take the chance.

Nonetheless, I stress that things under the hood being hot is not an abnorm al condition and does not necessarily indicate an overheating condition.

abnormal condition and does not necessarily indicate an overheating condition.

I'm in a third world country and scanners are scarce. Your explanation was very enlightening and thanks to you I think I fully understand the cooling system of this vehicle. I confused the pressure valve on the radiator cap for a mechanical thermostat. I have two more questions: Where is the coolant temperature sensor that operated the gauge located? And do you know (or could find out) what its resistance should be at the boiling point of water? Thanks a lot, am gonna start the thermostat, water pump fans test right now. Thanks again

The engine coolant temperature sensor/sender is located under the ignition coil, either in the side of the cylinder head or in the coolant manifold -- it's been a while since I've replaced one, so I don't remember, and the pi cture I have available isn't clear.

Because of the location, you'll want to test while the engine is cool rathe r than hot.

To test the sensor for the computer, check the resistance between the outer two terminals. The specifications are as follows:

-20C 14.13-16.83 Ohm

0C 5.79 Ohm 20C 2.31-2.59 Ohm 40C 1.00-1.30 Ohm 60C 0.57-0.61 Ohm 80C 0.31-0.33 Ohm

Unfortunately, I don't see in the shop manual a specification chart for the sender for the gauge. You'd test at the same sensor, but you'd check the resistance between the middle terminal and the sensor base or engine.

You should be able to access the service information at

or once you register with the site.

I did the test you suggested and the fan on the passenger side of the vehicle cycled on and off as you said, I guess this mean that everything is working ok... Do you know where I can get information on an Isuzu C201....I have a generator powered by this engine and it is passing fuel into the base. Some one suggested the injectors but the engine cranks and runs beautifully no smoke, everything seems fine just that it fills the base up with diesel pretty fast.

Both fans should operate. If only one operates, you should check the fan fuse, relay, and motor for the one not working.

I don't have a source for Isuzu information. But if this engine has a fuel pump driven by the engine (typically camshaft), I'd check to see if fuel is leaking through the pump diaphragm into the crankcase.

fuse, relay, and motor for the one not working.

pump driven by the engine (typically camshaft), I'd check to see if fuel is leaking through the pump diaphragm into the crankcase.

Both fans operate when I put on the AC, should they both cycle off and on with the AC off?

I thought you were describing the a/c fan initially, so that's why I though t the other should run as well. The a/c fan may not come on unless the eng ine reaches a second threshold temperature. If they both run when the a/c is on and one of them cycles when the a/c is off, I'll accept that as evide nce they're working normally.

I hope you don't get tired of my questions! The old battery could not hold a charge so i replaced it with a new one but now the fuel gauge does not work, there's gas in the tank. Is there a fuse that I can check, in other words is there a fuse associated with the fuel gauge? If there's one , where is it located? Can you provide a wiring diagram or schematic of the circuitry involved with the fuel gauge.

I cannot access either of the sites you gave me in the previous answer. I will need your help to obtain the electrical diagram that I need to repair my fuel gauge problem. Thank you.

Good Morning, I need some help on solving a fuel gauge problem.

Gauge was working fine until I changed the battery, now with gasoline in the tank the Gauge marks empty. I would like to know if there's a fuse associated with this circuit. I would also like to have a diagram for the fuel gauge circuit. I'm unable to access the Hyundai support sites you referred to in a previous post, I believe it is because the system detects that my IP address is from outside the USA?. Can You help? My car is a Hyundai Santa Fe 2001, 2.7 Automatic Thanks.

I'm not readily able to provide a schematic, as I'd be using the one on the sites listed.

The circuit is relatively simple.

The gauge itself has a power, ground, and signal. All the gauges are power ed and grounded at the same location, so if the other gauges are working pr operly, you already know it's not the power fuse or ground lug.

The signal wire runs through two sending units in series and then to a grou nd point. An open circuit will cause the gauge to read empty, and a short to ground will cause it to read full. You can access the senders by removi ng the rear seats and opening the flaps in the carpet to expose access pane ls.

Usually, one of the senders is open. Unplug one of the senders and jumper the two wires together. If the gauge comes off empty, that sender is open and needs to be replaced. If it stays on empty, try the other sender. If neither of these indicates the issue, you could have a gauge or wiring prob lem.

On the passenger side the sender wires are blue and blue/orange. On the dr iver's side, it'll be the two thinner wires, one blue and one black.

The gauge failed for few days and to use the car filled up the tanks and used the trip meter to keep track of the miles. Yesterday it started working again. I did nothing to fix it so maybe the problem will return but this time I'll be ready thanks to your valuable information. I love this old car......Thank you very much....