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Engine Overheating

Tiny
GOLDENTRAIL
  • MEMBER
  • 1997 HONDA ACCORD

Recently, I had an overheating problem. When I was driving, I noticed that the temperature is rising and going to the red zone. So I stopped and opened the hood while the engine is still running. I noticed that the radiator fan is not running even when the engine is so hot at that time. I turned the AC on and both the AC fan and radiator fan turned on. But making the fans turn on at that time could no longer lower down the temperature which was already above the middle mark of the gauge. Turning the AC off also turned both fans off. So I shut off the engine to let it cool down. When it was cooled down, I opened the radiator cap and found the level of coolant ok, so I discounted any possible leaks. I called a friend and was advised to check for the thermostat. But I dont know where the thermostat is located. Is it the one connected to the upper radiator hose or the one connected to the lower radiator hose at the engine side? I also noticed that the upper radiator hose is too hot while the lower radiator hose is not hot or is just warm maybe. Is it possible that the water is not circulating? What could be the problem why the fan is not automatically turning on when the engine is hot? Please advise. Thanks.
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Thursday, March 20th, 2008 AT 8:14 AM

129 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Mounted on the thermostat housing, which is at the end of the upper radiator hose, find the fan switch, test it and the relay in the underhood fuse box...If the fans work when a/c comes on it will most likely be the switch on t stat housing!

Check out this guide

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

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Thursday, March 20th, 2008 AT 8:34 AM
Tiny
GOLDENTRAIL
  • MEMBER
  • 3 POSTS
I tested the switch located in the upper radiator hose and shorted the terminals using a paper clip, but the fan didnt work. but when i detached and shorted the switch located at the lower radiator hose which is at the engine side, both the fans (AC and radiator fans) turned on. So what is that switch that made both the AC and radiator fans turn on? I am really confused if which is really the thermostat housing, is it the one on the lower radiator hose or the one on the upper radiator hose? I would also like to know how to test if the water/coolant in the cooling system is circulating or not. This is because i noticed that the upper radiator hose is too hot while the lower radiator hose is cold, so i presumed that the water is not circulating in the system. Inserted a picture here showing the connections. The lower portion of the picture with the green switch is the upper radiator hose connection, while the upper portion of the picture with another green switch is the lower radiator hose connection to the engine. Thanks.


https://www.2carpros.com/forum/automotive_pictures/170607_055_1.jpg

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Thursday, March 20th, 2008 AT 7:24 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
My mistake the one on the lower hose has the thermostat! In your case you may have a stuck thermostat, that will be the firest thing to change. If the water is cold at that lower hose, the switch will not turn on the fans! Flush and fill the cooling system while your at it. If after replacing the tstat, the fans don't work, replace the switch.
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Friday, March 21st, 2008 AT 6:00 AM
Tiny
GOLDENTRAIL
  • MEMBER
  • 3 POSTS
Thank you. I will try that. My problem now is how to remove the thermostat housing considering the many wirings and the big hose that are blocking it. Thanks again.
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Friday, March 21st, 2008 AT 7:17 PM
Tiny
JERSEYGRL1
  • MEMBER
  • 3 POSTS
  • 1997 HONDA ACCORD
  • 125,000 MILES
Thanks in advance for your help!

I have a 1997 Honda Accord LX (4cylinder)and it continues to overheat, although it's had major updates over the last 4 weeks.

Here is what has been changed out so far:
-radiator
-thermostat
-temp sensor
-catalytic converter
-1 fan (but neither are firing up and the relays have been checked and appear good)
-plugs & wires(for a different issue)

The weird issue seems to be that when I start the car and leave it in park, it can set for 15 or more minutes with the temperature staying where it always has. Slip into drive and the temperature starts to rise and pegs out in a mile or so.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
First of all, the fact that it pegged means to me that you had driven it overheated and most likely caused a head gasket to fail. You need a shop now that will do a leak down test to confirm. Hopefully, the head is not cracked but if the gasket is blown, it would explain a lot of your concerns.
If the gasket is good, I would look at the water pump as it may not be circulating the water at the proper rate.
As far as the fans, that may have been the original issue that caused all this. Signals from the ect sensor, relays and the fan motor itself are the components in the system.
By the way, did the fans come on when the ac was turned on?
Roy
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
JERSEYGRL1
  • MEMBER
  • 3 POSTS
Thanks so much Roy! We'll get it in to have that leak test done right away.

As for the fans, when the car was purchased we thought both fans were working, but later found that only one was, so the other was replaced. However, now neither come on, even when the AC is turned on.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
With air in the system, they will not work, the air may be the result of the head gasket. Take one step at a time.

Roy
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
JERSEYGRL1
  • MEMBER
  • 3 POSTS
Will do and thanks again. Will post the results.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good luck

Roy
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
LAURA COMEGYS
  • MEMBER
  • 1 POST
  • 1997 HONDA ACCORD
  • AUTOMATIC
  • 139,000 MILES
So I bought my car in February 2016 its now November 2016 my car kept overheating so I decided to change the thermostat just to find out there was no thermostat inside. After replacing the thermostat the car began to over heat to where I had to refill the radiator two to three times a day with coolant my car is still over heating, but nothing leaks from the radiator everything over flows out of the overt flow tank. What could be wrong?
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
You may have a blocked radiator causing little or redistricted flow. Have the radiator removed and core cleaned start here.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
STANBASE
  • MEMBER
  • 6 POSTS
  • 1997 HONDA ACCORD
  • 1.6L
  • 4 CYL
  • 2WD
  • AUTOMATIC
Want to know what causes periodic overheating of engine.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,871 POSTS
Need a better list of clues and observations than "periodic". Does this occur at highway speed? Slow, city driving? Any smoke out the tail pipe? If so, is it white? Are you having to add coolant or has the level dropped? Can you hear if the radiator fan turns on? When the overheating occurs, can you get really hot air from the heater or is it cold? Does running the heater bring the engine temperature down?
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
STANBASE
  • MEMBER
  • 6 POSTS
Hi
thanks for the answer. Will observe all listed occurrences.
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Tuesday, December 17th, 2019 AT 5:31 PM (Merged)
Tiny
MEJIA55
  • MEMBER
  • 1 POST
  • 1997 HONDA ACCORD
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 84,000 MILES
I have a 97 accord which has that problem. It overheated once and found out that it was the gasket. So ive had the gasket repaired timing belt water pump o2 sensors idle air temp sensors distributor etc. The car still runs fine but at times when driving prolonged amounts of time recently my needle goes up to the middle in the temperature gauge and last sunday it went up above the middle but not close to the red. So my question is what can it be since my mechanic drove it the other day in 110 degree weather for 45 mins straight and no overheating occurred. No oil leaks through the spark plugs or any of the sort. What do you think can be the problem?
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Tuesday, December 17th, 2019 AT 5:32 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
1st thing I'll do-is remove the thermostat and see what happens-if it gets cooler replace it- If not get the cooling system block and pressure tested.
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Tuesday, December 17th, 2019 AT 5:32 PM (Merged)
Tiny
CHIZZY77
  • MEMBER
  • 1 POST
  • 1997 HONDA ACCORD
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 172,000 MILES
I just purchased a 1997 honda accord and after a week it started running hot. When I open the hood I can see and hear steam coming out of the reserve coolant tank. I took it to a mechanic and he half-way looked at the car then explained that I need a new engine. He told me that my head gasket is bad on the pressure side. I dont have any money to buy a new engine. I dont want to believe that is the problem. I need a second opinion.
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Tuesday, December 17th, 2019 AT 5:32 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Even if it was a failed head gasket that would not call for a new motor. You will need to have a compression test done to see if the head gasket is indeed faulty though.
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Tuesday, December 17th, 2019 AT 5:32 PM (Merged)
Tiny
FANMAN9707
  • MEMBER
  • 6 POSTS
  • 1997 HONDA ACCORD
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 160,000 MILES
I had a thermostat go bad and did not catch it in time so I ended up with a cracked radiator. I changed the thermostat and the radiator and it stayed cool for a month or more now it is overheating again. The thermostat is working both of the hoses to it are warm, but the overflow is hissing and spraying hot water out of it. Is it possible putting to much water in the radiator and the resevior could somehow make it overheat? Or a clog possibly? When we reconnected the bottom hose we had to bend it just a little more than it was to get it to go on. I'm thinking this may also be the problem. Any other ideas would be greatly appreciated. Thank You
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Tuesday, December 17th, 2019 AT 5:32 PM (Merged)

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