Overheating started to hear the valves clicking ?

2017 HYUNDAI ELANTRA
97,000 MILES • 2.0L • AUTOMATIC
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Had my son take this car to get a tire changed from a place i deal with often 4 miles away. He had it changed the called and said car wont start. I went over and started it was rough, similar to that feeling when the intake boot is off. Notjing under the hood as far as disconnected hoses, water leak, oil, overheating symptoms, ran rough a bit then i managed to drive it. Then started to hear the valves clicking similar to what i would hear when a car overheats. Looked at age was above half. Stopped. Checked water level in reservoir and its full. Hoses not hard at all. Cold air so the fan worls too. Drove again, was just trying to get home, then lost power and saw the gauge alk the way up all of a sudden which makes no sense. Tirned it while driving and pulled into a parking lot and left it. Ill get it tomorrow. My question: could a bad coolant temp sensor cause this? If its false negative would it let the computer know to go for example in limp mode or not let me continue? Even though its not hot but the sensor thinks it is?
Jul 2, 2026 at 10:36 PM
Advertisement
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
And i noticed that it took forever for the temp gauge needle to move. I noticed that today while working on the radio. Took a while for it ti move
Jul 2, 2026 at 10:40 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, I bad engine temperature could definitely cause this, does it have a check engine light on and have you run the codes? Here is the location of the sensor so you can swap it out. Check out the images (below). Please let me know what happens.
Jul 3, 2026 at 6:38 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Didnt have the scanner yesterday ill run codes. No check engine light. Started kind of ok after he left it off for few minutes
Jul 3, 2026 at 6:59 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Did they change the oil when it has at the tire shop?
Jul 3, 2026 at 7:02 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
No just a tire. I was able to drive it to my office but then i saw the temp gauge at max all of a sudden. No busted hoses ir leaks or smoke or anything that indicates it being hot but motor started to bog
Jul 3, 2026 at 8:07 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, its sounds like the cooling system thermostat is stuck closed, I would replace it and recheck the operation.
Jul 4, 2026 at 2:21 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Am driving thr var back home a distance of 4 miles, noticed the rpm not working
Jul 4, 2026 at 7:53 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Am close to home but i think its in limp mode i cant down shift. No misfires or rough idle. Turned it off and on and it got out of limp mode and rpm is working . Also had the traction on and when i got home it was off. No check light or codes except for when going under permanent.
P335
P301
P303
P302
P300
Jul 4, 2026 at 8:04 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Started it again and its now dropping to 226f. But a bit of rough rpm then stablizes. Now 224f
Jul 4, 2026 at 8:07 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Video attache
Jul 4, 2026 at 8:50 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, it looks like the crankshaft sensor has gone out. The engine will still run with the camshaft sensor and the crankshaft sensor not working this will make the RPM gauge stop and the transmission shift funny or not at all.
Jul 5, 2026 at 2:37 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
where is it located on this one? it's a 2.0l motor. I suspected it but wanted to get another opinion
Jul 5, 2026 at 2:39 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
I found it. Rmeoved it and waiting on a replacement. Has oil on it which i guess is normal?
Jul 5, 2026 at 4:46 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep. sorry here is the location, and yes it should have oil on it.
Jul 5, 2026 at 8:00 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
replaced CPS today and it started immediately without having to start it twice, will drive tomorrow to confirm, thanks
Jul 9, 2026 at 1:26 AM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Sounds good let me know if that fixes it.
Jul 9, 2026 at 3:32 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
Kept it running a while while washing and all good took kt for quarter mile drive and it was fine on the way back all of a sudden goes up to max temp and idles funny. Stopped it and waited few then got home. Scanned it and was showing 262 dont make no sense it climbs that high that quick. Hoses are cool. Fan running, i also noticed no heat while driving, i was trying to get it to cool down. Even opened the radiator cap without any pressure and wasnt even hot. Then added water and started getting some smoke as you see. Let it sit then added ton of water most likely the radiator leaking . I just noticed few drops. Does the car go into limp mode if it overheats?
Jul 14, 2026 at 11:12 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, this will be the ECT sensor which you replaced correct? Or you have a bad connection at the sensor or the PCM is bad.
Jul 15, 2026 at 4:34 PM
Avatar
BHAMDOC1
  • MEMBER
  • 280 POSTS
no I only replaced the crank position sensor
Jul 15, 2026 at 4:37 PM
Avatar
STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Then I would do the engine coolant temperature sensor for sure. I show you here it is at above.
Jul 15, 2026 at 5:16 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.