I have a 96 Civic coupe with a 2000 GSR swap and I really need some help. Lately, the temperature has been creeping up and down and is driving me crazy. It never gets to the red, but sometimes will go about 3/4 of the way up the gauge and just sit there. It doesn't seem to matter if I am going 70 mph cruising for a few miles or just sitting in traffic. Also, sometimes it will all of a sudden just cool down to normal temp (without changing the speed I am going). But usually it will creep back up, eventually.

The first time I noticed this, I checked my fluid resevoir and it was empty. I filled it up and drove it for a while. I started to think my head gasket was blown, but the overheating was not consistent at all. Sometimes I can drive it about 30 miles and it will cool as normal. I finally found where I was leaking-a heater hose clamp going into the firewall had lost it's spring and wasn't holding. I replaced it with a screw type clamp and refilled the resevoir (it was just a small leak and the radiator was full when I removed the cap). I also went ahead and put a new radiator cap on it.

I went to drive it last night and it did the same thing. I went about 8 miles with no problem and then it started raising up to about 2/3 up the gauge and stayed there. I parked it at my g/f's and popped the hood. The fan was not on (which was wierd because it was so far up the gauge). I know the fans at least work sometimes. I tried to get my car to overheat at my house (I let it idle for about 30 minutes). It never went past normal and the fans kicked on when they were supposed to.

So-this is what I have figured:

The thermostat is opening b/c the car does not shoot to red, it stays about 2/3-3/4 up the gauge and will sometimes come on. If the thermostat was sticking closed it seems like the car would go to red and stay there.

Wouldn't the car cool fine when I am going down the highway even if the fan doesn't come on? It seems like there would be plenty of air coming through?

The radiator was replaced about 2 months b4 I bought it from the guy who did all of the work to it. The engine has about 75k miles on it and the timing belt/water pump were replaced at time of swap (about 5k miles ago).

I have not ruled out the possibility of a bad gauge or sending unit since I have watched the gauge needle pretty much FALL immediately from 3/4 way up to normal temp. I can't imagine water temp dropping that fast.

Let me know what you guys think...

Any thoughts, opinions are greatly aprreciated! Thanks in advance!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jonlee82 &raquo;</TD></TR><TR><TD CLASS="quote">I have not ruled out the possibility of a bad gauge or sending unit since I have watched the gauge needle pretty much FALL immediately from 3/4 way up to normal temp. I can't imagine water temp dropping that fast.</TD></TR></TABLE>

To me that sounds like an improperly bled system. An air bubble will do that. I could be wrong though...

 

^^thanks for the reply...
ok-if the fluid is all the way full in the radiator, do I need to let some out and then fill it while the cap is off and the car running? I have already done that once, but before I found and (hopefully) fixed my water leak. Is it possible that the leak was causing air to enter the system?

 

The bleeding procedure is in the Helms. You'll want to double check it, as my memory is famously inaccurate. As I recall, it goes something like this:

fill radiator
open bleed bolt
fill radiator more until bleed screw weeps with no air bubbles
close bleed screw, put rad. cap on to first click
run car until the fans cycle twice and shut off
refill radiator to top, replace cap, fill overflow to a tick over min, and go driving.

 

I don't know for sure, but I think your first instinct was probably right. It sounds like a thermostat to me.

 

if your fan goes on and you still overheat, then install a new thermostat and see what happens.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by coloweirdo &raquo;</TD></TR><TR><TD CLASS="quote">I don't know for sure, but I think your first instinct was probably right. It sounds like a thermostat to me.</TD></TR></TABLE>

That was my first thought too, but the way the gauuge reacts says it isn't...or at least, that there's something else going on. The gauuge takes between 15 and 60 seconds to change when the t-stat opens or closes, depending on RPM (flow rate), OAT/ECT ratio, the speed of the vehicle (cooling thru the radiator), and the phase of the moon. It may be a t-stat and a bubble, but I'm about 90% sure there's a bubble in the cooling system.

 

ok...I can see that...the thermostat is probably opening, but there is a air bubble in the system causing the weirdness. I will try bleeding the system correctly. I can not find a "bleed screw". According to my Haynes manual on SOME Integras it is right below the distributor at that upper water hose inlet. It is definitely not there. I looked for something similar but found nothing....any idea? Again it is a 2000 GSR motor.

Thanks a TON for the help guys!