Engine overheats, coolant leaks, coolant temperature sensor error

Hi Wodmay,

A temperature sensor may have caused the vehicle to overheat or not open the thermostat when it should have but the only thing that causes condition you describe is the continuous driving after the temperature gauge goes high. When the check engine light came on and the temperature gauge went high, you should have pulled over immediately and had it towed to get repaired. This would have prevented all that happened after that. Also, you don't want to get the coolant that is coming out of the engine and put it back in. Coolant needs to be clean and just coolant and water. When it leaks out and drips off the under-body of the vehicle or engine, it picks up dirt and then will contaminate your cooling system.

I would suggest at this point, performing a compression check on the engine to ensure you have not warped the head or done further damage to the engine. Next flush the entire cooling system and then replace any component that is leaking (if any). Lastly, address your code for the temp sensor and possibly the thermostat.

If you are going to perform this work, then I would not drive the vehicle until it is complete. If you are not going to perform it yourself, then I would have the vehicle towed to the shop that will perform the work.

Let me know if you have any other questions and we can go from there.

Thanks for your reply Kenny.
The mechanic said sensor is okay because fan is working appropriately on time. he is right now detecting the leak,he said the leak somewhere in coolant pipe creates the gas which turns the check engine light and coolant light on.. can a leak in coolant pipe cause the sensor error due to the gas? Could this all be due to the leak?The leak only takes place after I drive car for fifteen minutes. when we fill the radiator with new water car behaves normal until I drive for fifteen minutes and it starts leakage and shows check light. for those fifteen minutes car behaves totally normal. i am just confused.

I did not fill the dirty water back, lol. I filled the new clean water obviously.

This is the water leakage sample taken from below the car.. The leakage starts after driving car for fifteen minutes until then the car behaves totally normal.

It sounds like the engine is actually overheating and then the leak is a result of the boil over caused by the overheat. It is unlikely that the leak that doesn't take place right away could trick the sensor into thinking it is hotter then it is. Any time you are boiling over coolant, it is because there is excessive heat and the coolant expands to the point that it pushes out the weakest point which is usually the radiator cap/over flow bottle. If there is a leak in a pipe then this could be the weakest point so I would start with identifying excatly where the coolant is coming from when it overheats and repairing it if it is a broken component. Then drive the vehicle again, and see if it still overheats.

My opinion based on this info is it sounds like you have two issues. Maybe a pipe of some hose that is leaking and then an engine that is overheating. Even if you fix the leak, you may still have the overheat issue.

Keep me posted on what you find. I am interested to see what this root cause is. Thanks

You are right, leak was fixed and car was absolutely normal for a day when I drove the car and only coolant check light came up, I checked engine wasn't that hot and also the coolant container bottle was hot either, so I kept driving having no other option after 3 miles check engine came on and I reached back home, now in this morning when I started the car it is taking long self and started not so smooth fan kicked just after I started the car in the morning and fan is still kicking just after starting and starting the car is not smooth as it usually is... And yes when I came back home last night after check lights where on I touched the coolant container bottle it wasn't hot at all just 2 degrees hotter than room temperature... I am confused why is coolant check light coming up after driving for a while and car doesn't seem so hot? Why car worked normal for a day after I fixed the leak? Why is fan kicking just after starting the car.. Thr is no leak anymore

Can a bad sensor or bad relay create this problem of giving check lights and hard starting?

A coolant sensor probably will not cause the rough idle but I suspect you may have done damage to the engine IF it was truly overheating.

If the check engine light is coming on, then we should not guess at it and have the codes pulled because that will tell us what is happening. Do you have a scanner that can pull codes? If not, most parts stores these days will pull them for you. Let's get the codes and go from there.

It is really good news that it doesn't appear to overheat and the leak is gone, now the codes will help us figure out the rest. Let me know when you get them. Thanks

Few days back when the car was leaking I scanned the car it showed coolant temperature sensor circuit error, after fixing the leak the mechinc cleared the faults, when the red light comes unfortunately I can't scan at that time, when I go to scan my car thr is no red check engine light and hence no code. It shows glow plug code right now and nothing else, fan kicking just after starting, no visible damage to engine, engine had a cold start in the morning hesitated to start and was fine after reaching normal temperature and fan is the problem as far as I think,, it will kick in even in the morning when I start the car... Car starts normally behaves normal until I drive a mile and coolant light comes then after a while check engine light comes but i can't understand after I give rest to car the check lights disapaer and engine behave normal... Fan is always on now.. It was also on during the leak, then it was normal after fixing the leak for a day and started doing same again, could it be the problem with fan relay or fan switch? This morning when I started the car after reving for few seconds check engine light came on I rushed to get the scanner and the car died.. Then started normally again after and thr was no check light to scan, it happend all in just 1 minute.... I am confused..

Can you get a picture of the light that comes on after driving? That will help make sure we are on the same page.

As for the fan running all the time, that may be a default when there is a problem with the wiring or sensor. If it can't determine whether to turn it on or not, it will just turn it on to be safe.

When he cleared the code, did he happen to tell you what it was? That will help us check some things out depending on what it is.

This one first lights up.

This following the first on.

Okay. If the car is not actually overheating any more (or never was) but these are the lights that are coming on, then the PCM thinks it is overheating. In my mind, that is only a temp sensor.

This would mean it could be the sensor, wiring, or the module. See below for info on the sensor and how to test wiring. Then a video that is a little long winded but shows how to test a temp sensor. If you want just jump to 6:30 minute mark.

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works

https://www.2carpros.com/articles/how-to-check-wiring

https://youtu.be/eXNBlH0c4_U

Thank you. mechanic will change the sensor today and I will let you know.

Hello, everything is normal now after changing the coolant temperature sensor, thank you so much for your time sir.

Glad we could help. Please let us know if you need anything else.