Details:

1998 Civic DX Hatch
Stock 100%
Overheating

So I recently bought an EK (back in late October or November). I hate saying this because everyone assumes it's instantly the problem and ignores everything else.... buutttt, the previous owner blew the head-gasket. He had ALL the receipts for ALL repairs done. I still have all the receipts.

So recently the car started overheating during one night drive. I noticed it only overheat while idling a couple days later. Finally the other day I changed out the thermostat, I noticed that THERE WAS NO THERMOSTAT INSTALLED ALREADY. Also strangely the car did NOT overheat previously while it idled (like when I bought it). The car still overheats which brings me to this:

So here's what I'm pondering in my head. Maybe all the work that the mechanics wrote down that they changed, (the thermostat being one of them), was all a lie and still charged the previous owner. I'm really ****ing hoping it's not this cause then I might as well junk the whole ****in engine and swap it. (Don't just tell me to "swap it cause stock engine blows blah blah blah VTEC RULES!")

****ing ********, this is why I do all my own work.

Previously also when I bought the car I do believe that the fan turned on and all that jazz and kept the car running nicely while idling. Recently I haven't paid any attention to it but now though after we've done the thermostat swap I've noticed it won't turn on. I have checked to make sure it still works by hooking up a direct line with the battery, it does.

So my next "cheap fix" guess is the fan switch?

Mainly looking for more suggestions now.

(P.S. My brother and I have previously not bled the coolant correctly out of my EF but then realized what we were doing wrong and we fixed it, so I'm not saying it's impossible but we may have not bled the system correctly on the EK now...)

The car overheats still

 

Nobody? I wrote a short story I guess and nobody wants to reply now.

 

Start here:

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push/turn the dash heater lever/**** to MAX heat. Fan need not be on.

3) Follow the directions in the diagram below

 

Make sure you check all your fuses. This happened to my ac fan. The system starting over heating, bad fuse

 

8=D

 

Fuses are good as far as I could tell the one I saw was fine. (It said cooling system fan on it or something like that).

I plan on bleeding it on wednesday.

Any other advice?

 

Up.

 

http://techauto.awardspace.com/overheating.html

 

As per what I am reading, I assume you don't know how a thermostat work. A thermostat will shut off the path of the coolant to the radiator. When the engine is cold, no coolant flows through the radiator. Once the engine reaches its operating temperature the thermostat opens. The only thing that happen when you don't have a thermostat is for example, during the winter, your car will take longer to heat up because the coolant is cooled even if the engine is cold. So it is not strange, as you were saying, that the engine was not overheating because of no thermostat.

You are saying that you tried to test the fan and it work. Good news, your fan is good. You also said the fuse is good. Perfect! Now the next step would be to test with a Multimeter at the fan connector to see if the signal coming from the switch is reaching out the fan. I would ask the help of a friend to monitor the temperature while you are taking a power reading on the connector. If your friend see that the temperature is getting higher than normal and if you don't mesure anything at the connector, you have your answer. Shut off the engine as soon as possible once you get your reading.

What RonJ@HT show you to do is another good way to ensure you have no air in the cooling system. It is mandatory to have NO AIR in the system as you already know.

I just hope you don't have a case of a cracked head. One way to check this... Open your radiator cap when engine is cold, start your engine. If coolant is ejected 12038971289037 feets high, then you have either a wacked head gasket or a cracked head.

As per what you are describing, it really seems that you have a problem with the fan not turning on. Be happy if it's the case!

 

Do you test the switch in Ohms? If so what is the reading? And what do you set the multi meter to?

Or is is volts?

 

It would be volt. I don't remember if the signal sent by the system is a 5V or a 12V. But like I said, it is very important to not let the engine run that way or it will overheat. (the engine is expecting the coolant to be cooled in the radiator)

It also explain why it's only when you are idling that the engine overheat. The coolant is cooled naturally through the radiator because of the wind when the car is moving. =

 

The only thing that puzzles me if it volts, they only way to test swtich itself is to unplug the connector, if no connector how can you get voltage to it? There will just the switch to the thermostat housing, that is why I was thinking ohms?

 

If you bypass the switch (jump the 2P connector) and the fan runs, then the switch is the problem, assuming that the cooling system is properly bled and full of coolant. Keep in mind that Civic engines tend to run cool, so the fan does not normally run continuously.

 

I was taking a power reading right at the connecter on the fan.

^^ 100% right and way more easier to test the switch... i never thought about that. Thanks Ron

 

I'll definitely be trying this, thanks Ron. Also thank you Moonraker, I do believe you may of interrupted what I wrote incorrectly or maybe I typed what I was thinking incorrectly. I was quite tired at the time of the first posting. I do know how the thermostat works but thanks for the informative post.

I have another question though about bleeding the system and the fan. If the system is not completely bled will the fan not recognize that the engine is overheating and that it (the fan) should turn on?

 

A pocket of air around the switch will interfere with its ability to monitor coolant temperature.

 

I had my car running hot recently, bleed it for 25 mins and seems better, right at 25 mins it blurped coolant I am assuming that was a last burst of air getting out.

 

anytime my friend!