2001 honda civic running kinda hot? Fix it or leave it alone?

[SacTown]

Ok so I just bought a 2001 civic ex 2 door manual trans from a dealer last week (Kinda janky used car type place). The car had so little fuel that the test drive was less then a mile. (first red flag). My wife loved the car so we bought it. on the way home the temp gauge went to 3/4. I called the dealer and to his benefit said just bring it back and ill have my mechanic look at it. I bought the car "as is" so I was happy he would at least look at it.
2 days latter he called and said he thinks its the thermostat and is waiting on the part from Honda. 2 more days and he calls and says the car is ready and he changed the thermostat. i picked it up after work and same thing happens again. He now dosnt want to do anything and says its a faulty gauge and the car is not over heating.
This is now my problem and Im hoping someone has an idea what I can do to fix it. The gauge starts at 0 and slowly rises to 3/4 hot. running the heater or air conditioner does nothing to change the temp. the car runs perfect. No CEL. no hesitation just runs hot. any ideas on what it could be would be greatly appreciated Thank you in advance for your time. cAR IS 100% STOCK NO MODS

 

[young_]

Radiator could be clogged. It could be as simple as the radiator cap. Does the water pump leak at all? Any coolant spray up under the good? Any smoke out of the tailpipe?


Sent from my iPhone using Tapatalk

 

[SacTown]

No visible leaks. I will check better in the light tomorrow. Is it bad to drive it like this? Its not hitting red line?

 

[SacTown]

update

ok so no leaks that i can see. The dealer says its just the gauge but I dont fully believe that. I did a "hill billy" test though. What i did was start the car and let it idle until the gauge said 3/4 same as its been doing. (about 1 min) then I popped off the radiator cap...... No steam no shooting water. nothing. I even stuck my finger in the water. It was hot but not burning hot. more like hot shower hot. I feel that must mean that its actually not getting hot. but for some reason it says hot. Any ideas why this may be happening? I am at a loss thanks.

 

[taluzer45]

It could be as simple as a fan switch.... do the fans kick in? If not then disconnect the fan switch terminal on the thermostat housing and jump it with a wire when the car is off, then turn the key to the on position... the fan should kick in! If it does kick in it means that the fan switch is gone... it only costs like $50 at the most! Ive had the same issues when I bought a 2002 civic LX...

 

[young_]

ok so no leaks that i can see. The dealer says its just the gauge but I dont fully believe that. I did a "hill billy" test though. What i did was start the car and let it idle until the gauge said 3/4 same as its been doing. (about 1 min) then I popped off the radiator cap...... No steam no shooting water. nothing. I even stuck my finger in the water. It was hot but not burning hot. more like hot shower hot. I feel that must mean that its actually not getting hot. but for some reason it says hot. Any ideas why this may be happening? I am at a loss thanks.

I had this problem with my integra. Turned out to be the coolant temperature sender. Goes in the side of the motor under the distributor.


Sent from my iPhone using Tapatalk

 

[SacTown]

update

ok so I took it to a friend who did a resistance test on the "sending unit". said it had the same ohms on both leads coming from the "sending unit" so it should be good. he asked if i could find an engine performance wiring diagram. because there is 5 leads coming from the sending unit that he dosnt know what they are. He seems to know what hes talking about and maybe im not quoting him correctly but does anyone know where i can find this diagram i have googled it but dont really know what Im looking for

 

[00siboy]

Sounds like you have air in the cooling system. If your radiator cap is not holding pressure it allows air to enter the system, which would cause temperature problems and bad readings by your temp sender. Since the t-stat has been replaced, you could start by replacing the rad cap because its cheap, and go from there. Also like young_ said your radiator could be clogged or your water pump has gone bad, basically your coolant is not getting circulated.

Next, start the car cold and keep and eye on the gauge to see when/if the radiator fan kicks on. The best thing to do would be to look at a live datastream on a scanner to see actual coolant temperature, but you probably don't have access to one. You could also try flushing the radiator with a hose.

 

[SacTown]

actually the guy who was working on it had a "live data scanner" and says the fans are turning on at the right time. I think he said 205 degrees. He also said its not over heating at all but I will go get a radiator cap today. Any one know about the "engine performance diagram"? Everywhere on line says I can buy a download for 6-8$ but I want to make sure I am getting the right diagram before I pay for it.

 

[00siboy]

What diagram are you looking for? If you are asking for a service manual with diagrams then I could try to send you online to where I found mine, but its for a 6th gen.

I'm still leaning toward it being a coolant circulation problem. Is the coolant clean or does it look a little dirty?

 

[SacTown]

Clean.