2000 Integra LS 5spd. 125K miles. Stock except for I/H/E. No CEL's.

I was driving today with the a/c on and when I was almost home I noticed that the temp gauge was at the middle. And this surprised me, it is never at the middle. Its always at about 1/4, and never goes up at all. In fact sometimes when its cool outside its goes down even further to about maybe 1/6 or 1/8 of the gauge.

I continued to drive, after about 30 secs it went back down to the normal place about 1/4. Got home popped the hood, no steam, plenty of coolant in the catch can reservoir. Hoses intact. However I kept the car running and both the lower and upper radiator house were able to be depressed. Meaning that there wasn't any fluid running through them. Even though the hoses were empty and there was no pressure in them, the temperature looked fine, and the engine was running normally, and didn't even feel very hot, so I'm gonna say that the temp gauge is correct. Waited a few mins and eventually the fans kicked on like it normally would when running the car when stopped. Fans kicked back off and the gauge never moved, just like normal operation. I never checked to feel when the hoses were pressurized when the car was running. Is it normal for them to be unpressurized at operating temps ? maybe the thermostat was closed I guess, but it just seemed like it would be open considering I just came back from a 45 minute drive. I just wanna know if its possible that maybe I have air in my system. Or do I have something to worry about ? It's due for a radiator flush, maybe a thermostat to.

Any Ideas as to what happened or if everything sounds ok ?

 

Just because you can depress the hoses, doesn't mean that there is no fluid flowing through them. How long has this been going on? Seems as if your due for a flush, and a thermostat change, go ahead and do so. There are ways to test of your coolling system. You can buy them at any automotive store. Its seems like your system is okay. I would get a hotter thermostat though. Your builing up a lot of sludge....

 

Yea that's what I've been thinking. However the car never runs hot. I've only just noticed this now, I mean I understand how the cooling system works. I actually went back outside later and checked the rad, its completely full, and no signs of rust or gunk in the system. Started her back up and I had pressure in the hoses. My guess is that I need a new thermostat, and a good flush. When you say hotter thermostat you mean that it opens up at a hotter temp correct ? Ie. opening at say 180* as opposed to say 160*.

 

Yes. I have always used the 170*. the temp guage isn't half, but its close. If your radiator is full, chances are that your cooling system is operating correctly. Maybe the car got a little warmer due to the fact that the engine was working a bit harder W/ your AC on. Good stuff.

 

Well the only thing that worried me alittle is that I've had the car for a whole summer already, and I've daily driven it through rush hour traffic stop and go with the a/c on and the temp gauge has never gone above 1/4, its only gone below 1/4, never above till the other day. So do you think that maybe the thermostat is possibly malfunctioning and closing when it shouldn't or maybe I just need to flush the system ?

 

is it just when u have the ac on? i would just flush it and put in a new ts.. my integra would allways stay at the 1/2 point after warmed up . but my wifes integra would always be different when warrmed up and she never have had a problem with it over heating besides when the hose that gose to the tb had a hole in it.

 

check ur water pump getting good flow also maybe air pocket in system i've had that happen

 

I've been watching it, and for the past couple days it's been perfectly normal. I've been running the a/c alot when commuting to work and there have been a few warm days recently here in FL. Id have to assume that I had a air bubble in my lines. I'm still going to give it a good flush and replace the TS. Its due for it anyway. I'll keep you guys posted if I see anything abnormal again. What TS do you guys recommend ?

 

i say its the thermostat, if your temp gauge starts to climb when your idling then when you drive its goes back down, 9 out of 10 its the thermo, make sure u the next one u get is failsafe, as in, when it goes bad it stays in the open position...

 

So I was wondering, how does that work? If its malfuntioning how does it know to stay open.. just cirious