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hj3 · Apr 20, 2008, 09:47 PM

I have a 1998 Honda Civic LX 4 door sedan. It was in an accident awhile ago and since I got it back, the temperature gauge has been fluctuating from regular warmth (mid gauge) to hot (towards the top), only to be brought back to the middle when I turn on my heat. When I turn my temperature level from hot to cold, the gauge perks up real hot to the top, only to go back to the middle when I put the temperature back to hot. I just changed my radiator today with a brand new radiator and I changed my rubber hoses for silicon hoses. I also drained and flushed my system as best as I could before I put the new components in. I used some radiator cleaner and then kept draining flushing and refilling with water (in gallon jugs since my apt. building doesn't have a faucet on the exterior where I could plug a hose into) until I saw little to no green antifreeze, then I filled up with orange antifreeze - diluted 50/50 with distilled water of course. I test drove the car on the street and on the highway and am experiencing the same symptoms - the temperature gauge keeps fluctuating from mid to hot only to go to mid and stay at mid when I turn the heat on. I have no a/c freon in my lines if that matters - I never refilled it since I got my car back. Could that be the reason? What could be the reason? (I forgot to mention - before I changed all of my components and liquids, I put in a new thermostat.) Thank you & have a good day.

rtw_travel · Apr 21, 2008, 11:06 AM

I am not familiar with your specific car - can you tell me if it has an electric fan either in front or behind the radiator? If so, does it work?

TxGreaseMonkey · Apr 21, 2008, 11:18 AM

According to a Honda-trained mechanic I talked to last week, the primary causes of Hondas overheating are:

1. Electric radiator fan not working, and

2. Thermostat installed incorrectly.

hj3 · Apr 21, 2008, 12:15 PM

Originally Posted by rtw_travel

I am not familiar with your specific car - can you tell me if it has an electric fan either in front or behind the radiator? If so, does it work?

Hello. The electric fan is located behind the radiator i.e. in the area going towards the engine and everything else under the hood. Does it work? The most I can tell you is that when I kept my hood open and observed the area, the fan never turned. Is that a symptom that it doesn't work? Would that mean I'd have to get a new electric fan - or - should I check the electrical connector first? It's plugged in so should I check to be sure a current is going through it before purchasing a new fan? Thank you very much for your response.

hj3 · Apr 21, 2008, 12:20 PM

Originally Posted by txgreasemonkey

According to a Honda-trained mechanic I talked to last week, the primary causes of Hondas overheating are:

1. Electric radiator fan not working, and

[Would it be the fan or the connector. The connector is plugged in. I just asked that to know whether I should test the connector to see if a current is going through it before buying a new electric radiator fan.

2. Thermostat installed incorrectly.

[Wow really. The way I understand it is that you take the thermostat, put the gasket around it, open the thermostat housing, put it in (the part where the circular piece on the end is smaller is the piece that goes into the housing), then close the housing, attach the hose and call it a day. Could I have mishandled it or is there some other way I have to install it? Thank you very much for the reply.

rtw_travel · Apr 21, 2008, 01:07 PM

Originally Posted by hj3

... Does it work? The most I can tell you is that when I kept my hood open and observed the area, the fan never turned. Is that a symptom that it doesn't work?

Perhaps someone else familiar with your car can give a more detailed answer.

Electric fans will normally have a few different sensors to turn them on: the obvious one is one or more rad outlet temperature setpoints, but often they turn on whenever the A/C is turned on too. If you can find out if the A/C also operates the fan on your car, then you have an easy way of troubleshooting the fan operation (without risking an engine overheat)

If it is a fan problem, then it could be the fan, a relay, the resistor pack or other electrical device Honda used to vary fan speed (if the fan is variable speed), or perhaps even a wiring problem (caused by the accident?).

Based on what txgreasemonkey says, I'd say to check the connector for voltage when you figure it should be running. If there is voltage, then replace the fan.

BTW, you do not want to let the engine overheat - it could lead to warped heads.

hj3 · Apr 25, 2008, 03:49 PM

Originally Posted by rtw_travel

Perhaps someone else familiar with your car can give a more detailed answer.

Electric fans will normally have a few different sensors to turn them on: the obvious one is one or more rad outlet temperature setpoints, but often they turn on whenever the A/C is turned on too. If you can find out if the A/C also operates the fan on your car, then you have an easy way of troubleshooting the fan operation (without risking an engine overheat)

If it is a fan problem, then it could be the fan, a relay, the resistor pack or other electrical device Honda used to vary fan speed (if the fan is variable speed), or perhaps even a wiring problem (caused by the accident?).

Based on what txgreasemonkey says, I'd say to check the connector for voltage when you figure it should be running. If there is voltage, then replace the fan.

BTW, you do not want to let the engine overheat - it could lead to warped heads.

Hello. I checked the a/c on my car and let it run for roughly 2 minutes to see if the fan would run in order to see if voltage was going thru. The fan started spinning in a minute to a minute and a half. So perhaps I have a bad fan? Is that/could that be the case as you stated?

hj3 · Apr 25, 2008, 03:50 PM

Originally Posted by txgreasemonkey

According to a Honda-trained mechanic I talked to last week, the primary causes of Hondas overheating are:

1. Electric radiator fan not working, and

2. Thermostat installed incorrectly.

Hello. I checked the a/c on my car and let it run for roughly 2 minutes to see if the fan would run in order to see if voltage was going thru. The fan started spinning in a minute to a minute and a half. So perhaps I have a bad fan? Is that/could that be the case as you stated?

rtw_travel · Apr 26, 2008, 06:36 AM

A delayed fan start when you turn the A/C on is not unusual. The fans works fine.

I wonder if it is a faulty thermostat. There are just not too many things that could go wrong.

mrvladybug · May 29, 2009, 09:05 AM

I have the same car and the same issue. After replacing the hoses, thermostat, radiator, head, everything we have come to find that the gauge itself is faulty... We have tested the car at numerous times and even though it SAYS it is overheating all hoses show it at 182 degrees... You may want to have the hoses temperatures checked... your gauge may be bad as well.

serzh_a · Jun 22, 2011, 03:52 PM

How can I find out if the gauge is not working correctly?

isaacflores · Jul 9, 2011, 04:43 PM

I have a 1998 honda civic lx and I just had my oil change, radiator flushed. Two days later my radiator gets a crack. Money down the drain on flushing the radiator. I replace the radiator with a new one. My cooling fan relay goes out. Ireplace that and the thermasta.my heating/cooling gauge is now rising to hot and falling to cool. There's not much more for me to replace for the cooling fan. How do I know if I put the thermastat in wrong?I have no leaks and no water in the oil. Is there another sensor that I missed or should change? How about the engine cooling sensor?