98hatchhonda

Hey guys. Recently bought a 2002 Honda Civic ex. We flushed the radiator and replaced the upper and lower radiator hoses (note we only did the radiator, didn't take the drain bolt off the engine and drain coolant from engine). We flushed radiator and filled radiator up with coolant and then filled the coolant reservoir half way between the min and max lines. Then had the radiator cap off and ran the engine till it was warm. Well about two days ago I drove around and decided to check under the hood for leaks etc just to keep an eye on stuff and apparently coolant overflowed from the reservoir tank. Checked the reservoir tank and it was very high, and then when it cooled checked the radiator and the radiator level was down just a little , not much at all. I pulled some of the coolant out of the reservoir tank.

Well today I was in a drive thru getting food and then my temperature gauge started to go above the regular running temp slightly. It didn't get up to hot or anything, didn't make it past the middle mark. I cut it off, popped the hood and once again coolant has overflowed from reservoir. Drove the car home and it ran at perfect running temp all the way home.
Got home, let the car cool down and once again the reservoir tank was high but the radiator was lower than it should have been.
What could be the cause of this?
There is NO white smoke coming from the tail pipe...car does not run rough whatsoever, doesn't feel like I have lost power. Oil is nice and healthy, and coolant looks good and clean.
Could this be air in the system from when we replaced hoses and flushed system?
I have the radiator cap off my 98 civic hatch d16y7 on my civic I have now but I don't think the caps are different. Radiator fans kicked on after I let it idle for a few. I do have hot heat when I turn the heat on.

What could cause this guys?

NDNV

Bad head gasket or air the coolant system. The HG is a common issue with these engines.

civichxtreme2

^^ Id say air in the system as well

98hatchhonda

I'm thinking air in system..car ran perfectly fine today, drove it for bout 20 mins and no issues. After the drive thru incident it ran fine on the way home as well.
Popped the reservoir tank and it wasn't high like it was after all that happened (of course we drained some coolant out of the tank last night and got the level to regular level as it should have been.)
I'm letting the car cool down right now and I'm going to check the radiator level once it cools. I'll update afterwards

jpking17

My 2003 acted very similar when the head gasket went in it. Driving down the road it would be fine and when I stopped the temp gauge would climb (learned to shut off the engine when I saw this happening). The reserve would have fluid in it but when I checked the radiator it would be low. I did not have any smoke and did not have any coolant in the oil. I had a friends buddy replace the head gasket and have been fine since....he showed the the head gasket and where the Teflon had worn off it which is where the coolant was escaping and then evaporating slowly (why there were no leaks). I'd say keep an eye on it...mine started very gradually.

98hatchhonda

Dang that sucks ! I let the car cool down and I checked the radiator and it was full with coolant and the reservoir was normal. So I'm going to be keeping an eye on it. Hopefully it was just a small air pocket that caused the temp to go up very little

Maluko

https://honda-tech.com/honda-civic-2...e-etc-2889523/