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Coolant Temperature rising

My coolant temperature been going up and down. It did it for the first time Fri night when i got off of work but o drove it the next morning and it drove just fine no problems at all. Then i drove it again Sun and had no problems again, drove it to work today no problems but when i got off of work tonight it was rising again. What could be the problem? It cant be the head gasket could it cause if it was it would be rising everytime i drove or am i wrong? Im asking cause the head gasket is the worse case so im hoping it may be something small. Btw idk if this helps but when i get off of work at night i take the highway when i drove to work i take the back roads, that sat morning and sun evening i didn’t drive on the highway either. Could that be the issue high speed?

Have you checked the coolant level, in radiator and overflow reservoir ?

Yes i checked it Sat it’s full.

You have told us nothing about the car. I see on your profile it might be a Honda Civic but no other information. If you want some help, post information about the car - miles, engine, transmission, any service history ect.

You might also mention if you are going to try to fix it yourself or take it in for repair. Help us and we will try and help you.

Its a 05 Honda Civic EX, it has 135,000 miles and if its a easy fix I’ll do it myself.

It’s a 05 Honda Civic EX with 135,000 miles on it. I’ll fix it myself if it’s a easy fix

I just replaced the thermostat on my 1999 Civic with a new genuine Honda stat. It was 19 years old and I had noticed occasional slight variations in the temp gauge starting on a very cold night last winter. Haven’t driven it a lot since, but it seemed like a wise precautionary move. Over many years of observing there’s never been any head gasket symptom, but there’s no guarantee, and you don’t want to drive far if it does fail.

Ok, then, as others have posted, first check the level and the condition of the coolant. If the color hasn’t gone brown-ish or oily and it remains full then good!

Next make sure the fans are running with the AC being on. Get the car up to temp and maybe a bit over. Check to make sure at least one fan is running. It helps cool the car in traffic. On the highway, the airflow is high. If it is running, good. Turn on the AC, does a second fan turn on or does the single fan run faster (you can tell by the noise). If the fans are working, great.

That means the thermostat probably should be changed. You should be able to find a YouTube video of someone changing a thermostat on a car very similar to yours. T-stats are cheap, consider buying one from Honda. Just be careful not to install it backwards. When you re-fill the lost coolant, start the engine, but the heat on full add until the the full line. Drive it around and add more coolant if the level is down - and it likely will be.