Why is my engine overheating?

It does sound like the fan is not working which is probably a bad fan motor which is common but to be sure lets run down these guides to help us fix it.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://www.2carpros.com/articles/replace-electric-fan-motor

and

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

Please run down these guides and report back.

It happens when I'm doing long drives on the freeway. When the car b is under more stress I guess. By coolant you mean water right? Sorry I'm not to experienced.

If overheating occurs only when driving at high speed, that means inefficient cooling and the most likely cause would be restricted radiator.

Yes, coolant is the fluid used in cooling systems. Did you check the radiator level?

When I got home I took off the radiator cap and filled it up with water but it filled uo with just a few ounces.

Have the radiator checked for clogging.

I installed a new fan motor and it started working and the engine does not overheat anymore thank you!

You're welcome.

Ok, I have brought my car to my mechanic twice for this issue, and they can't find a thing wrong. My thermostat fluctuates, sometimes going all the way to H. I turn the heat on, and it goes down. Last night it was doing it again, so we tried not turning the heat on, and the thermostat stayed up to H for a minute, then slowly went down on its own. What is wrong with this car?

low coolant level, bad thermostat, clogged radiator or a blown head gasket. since you have driven it overheated, i would have that checked first

Roy

Thank you for responding! I have had a pressure test, thermostat was tested, the whole car, and the fluid level is checked every morning, just to be sure. The whole car is fine, is there anything else, or is it a recall issue?

no recall, everything is not fine. one of these items is creating your issue and you need to have someone track it down before you do serious damage to the motor from overheating.

roy

Check the cooling fans. They could be working intermittently due to failing motors.

Thank you KH!

I agree with KH but the fans cool at idle not at higher speeds as you indicated.

Roy

Thanks ASE, my car had been referred/brought to the dealership, where even they are having difficulty figuring out the issue, as it is not doing it for them, and they cannot find a broken cracked or leaking part. Thanks to all! Hoping the dealership can determine the issue, as I really like my car! I was just hoping for some ideas :)

good luck

Overheats after driving eight to nine minutes. Changed both thermostats tested old both opened. Low coolant never see leakage. Was told 20,000 when I bought blown head gasket or cracked head also they added sealer in radiator copper bits in rad not much. No problem for 18,000. Burped coolant. Car sits in driveway at startup fifteen minutes does not overheat, the fans come on when temp rises to just above normal.drive it seems okay for nine minutes. Six months ago hot day AC stops. Month later had low coolant a couple times I added more okay. Then temperature rises on hot daytime +80 driving but could be controlled with heater on. Let temperature rise almost to the top of gauge a week ago. Since then overheats more heater is not enough to keep cool. This week replaced two thermostats did not burp correctly. The next day burped fifteen minutes properly had bubbles etc. Now at normal temperature in neutral for burping today again okay in driveway drive it eight to nine minutes overheats. I cannot be sure top thermostat little hole is in correct position. I looked for one but do not recall seeing one. Thanks

Hi and thanks for using 2CarPros.com.

Since you have already replace the thermostats, bled the air from the system, and the cooling fans are working, I would recommend flushing the radiator. You mentioned using a stop leak product. Often times, they can actually melt down and plug the radiator, heater core.

Take a look through this link:
https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

Next, since coolant is disappearing, either there is a leak or a bad head gasket. Here is a link that discusses the process of locating a leak:

https://www.2carpros.com/articles/coolant-leak-symptoms

Last, here is a test for checking for a head gasket issue:

https://www.2carpros.com/articles/head-gasket-blown-test

Take a look through these things and let me know if you have other questions.

Take care,
Joe

Hello
I flushed the radiator, burped it. Then is sat running in the driveway for ten minutes does not overheat. I noticed the tiny bubbles in the coolant. However, I rigged a funnel to the radiator opening to have coolant above the radiator that is when I noticed the bubbles. While parked no problem I drove it for five minutes and it got almost to the top of the gauge. Seems like a head gasket.

Also the car sits in neutral (manual transmission).
No overheat issue, I can turn the AC on when the engine is still very cold and right after start. The fans will come on. Is that normal?

Honestly, it sounds like a head gasket. Take a look through this link and let me know your thoughts.

https://www.2carpros.com/articles/head-gasket-blown-test

The car sits idling after startup for thirty minutes with or without the AC on. It does not overheat. I drive for seven minutes and it then overheats.
The car has two thermostats top "water regulator stat" I believe may be upside down with the tiny hole might be on bottom. I saw tiny bubbles after drain and fill radiator. Consistent bubbles in the radiator.

Yep, it sounds like a head gasket. Below are diagrams to help you see how the job is done. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken

Thank you all for your help.
Sold it and bought a 2015 Passat.

Good to hear, please use 2CarPros anytime we are here to help.

Cheers, Ken

After running the engine or driving for at least 30 minutes it runs hot. I've noticed one of the cooling fans runs at a medium speed and the other won't start unless I give it a spin with a hand and then it moves but really slow. I'm suspecting the thermostat but it seems the fans could be an issue as well. I replaced one of the three fuses that are for the fans and before replacing it only one fan worked. I'm not sure in this case what the cause may be

the fan you have to start by hand is bad for one thing, have coolant system pressure checked for coolant leaks and when hot check radiator for cold spots if you feel any cold spots rad is bad.

Thanks, the fan was definitely the culprit. I've replaced it and now no more overheating.

my car about a month ago started to overheat. funny part is the temp goes up and comes back down. we have replaced both thermostat, water pump, and my starter.

the car over heats when it wants to at any particular time. we have done flushes, oil change, pressure test and all and still the same thing. the service engine shows me the oh2. there is no leaks at the bottom of my car, the radiator seems to have coolant. the odd thing is that i did have to add antifreeze to it since it would run low every 3 to 4 days.

is the head gasket the next step????

The temp gauge is probably bouncing around because the cooling system is full of air pockets. Your first step is to fill and pressure test the cooling system to see if it holds pressure.

Engine Cooling problem 4 cyl Two Wheel Drive Automatic 113500 miles

My automobile recently started overheating when I travel at 60 to 70 mph. When this happens the air conditioner stops working. I had the freon checked and the cooling system has no leaks and has coolant. As long as the temp guage is normal the air conditioner works fine, the problem starts when I'm on the freeway at a high speeds.
What could be causing the problem?

When the computer sees the engine starting to get to hot it will turn off the air conditioner. This is most likely caused by a plugged radiator either internally or externally. Here are some guides that will help you see what the problem is so you can fix it.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://www.2carpros.com/articles/how-to-replace-a-car-radiator

Please let us know what you find.

Cheers, Ken

Engine Cooling problem
2005 Nissan Altima 4 cyl Manual 64000 miles

Dear Mr. Expert!
I drive a Nissan Altima 2005 and the engine has overheated twice in the last 6 months with no apparent reason (i.e. normal temperature gauge reading), leading to oil/water contamination in both cases�
The first was at 97,000Km mileage. The head gasket was blown and the cylinder head surface was affected. The overheating was due to the failed lower cooling thermostat/valve, and the temperature gauge didn�t go up since there was almost no coolant in the radiator as the mechanic explained (due to internal leak). The repair job included replacing the gasket and straightening to the cylinder head surface. The 2 thermostats were replaced along with the water pump.
The second failure was at 102,000Km (5 months later). One week earlier I started to notice little coolant decrease which went large within a week (almost empty overnight). The temperature gauge didn�t go up this time either and the engine didn�t run on an empty radiator, since I was checking and adding coolant consistently. Upon engine disassembly, there was almost minimal to no damage to the cylinder head and its surface, but the engine block was affected and its surface needs to be straightened�
The concern is that there is no apparent reason for overheating, especially with the second failure. Could the temp gauge be broken, or it�s all because the repair job wasn�t done properly the first time? For the record, the engine block was NOT checked for straightness the first time.

It i spossible the head was damaged the first time and it wasnt caught. Cylinder heads should always be pressure tested as well as surfaced before reinstallation to ensure there are no cracks.For a block to warp is pretty difficult compared to a cracked head.

Thanks for the swift reply... really appreciated...

Do you mean there has been a subtle crack/damage in the head, which wasn't caught the 1st time and has led to the second failure?

My mechanic is contending that if this was true, then the engine would have failed immediately in less than 24 hours after repairing it the first time, not to mention that the car has made 5000km between the two failures...

Does he have a point here?!!

Just to confirm, with the 2nd engine disassembly and upon visual inspection, there's no apparent crack in the head (only surface was slightly affected), but the block surface is affected this time (slightly warped)...

Sometimes the cracks can be so slight they dont create problems for awhile. Was the head pressure tested the first time? What is the amount of warp in the block? It is very difficult to warp a cast iron block, vs an aluminum cylinder head.

Hello

No, the cylinder head was NOT pressure tested the first time...

Something to notice is that the engine block for this car model is Aluminum too...

For the amount of warp occured in the block, I'm not exactly familiar with the measures here, but when the block's surface was tested for flatness, there was a clearance of about 0.5mm at the center, where you can move a piece of paper almost freely within it...

Looks like the limit for that is .1 The block will have to be removed, taken apart and decked

Buying a whole engine (used one) would cost the same as replacing the head and decking the block... this is where the case is actually going now

Actually what i'm really concerend about is the CAUSE of the SECOND FAILURE... Was it because:

1) A bad 1st repair job ...... OR
2) Overheating again

I attaching 2 photos of the cylinder head after the two failures... From the comparison you may notice the head was muh less damaged the 2nd time (the red circles only) whcih makes me more convinced it didn't overheat

the issue seems complicated to me.... if u need more details and clarifications then I'm ready

Hard to say.... the warped deck (block) may have contributed to the second failure.A warped block is much stronger than awarped head and it will force the head to bend to conform