[ikenewton82]

Just going to put out there in case someone has experienced this before, I have a 2008 civic hybrid, 340k miles, over the last few months it has been overheating, mostly when I go over 50mph, but cools down after I slow down, at idle it's fine, had it on for over an hour and the temp stayed good. I replaced the cluster because it started to fluctuate, on temp it would behave like the mpg does, they share the same line so I figured it wasn't overheating, the activity was based on the mpg I was getting going up when I cruised and drop when accelerated, the cluster has a diagnostic mode and after doing it it had error displayed, after cluster replacement it got better, weeks later it kept showing hot, just not erratic like before, I replaced the water pump, thermostat, dumped the thermo in boiling water and it opens, rated at 192 degrees, flushed the radiator, flushed the heater core, then bypassed the heater core to eliminate that altogether, replaced both sensors, radiator and engine sensor with oem type, pressure tested the radiator and held, tested the radiator with chemical to see if the head was leaking into the cooling system and no color change, replaced relays and fuses, nothing, still overheats, monitored the temp on scanner while driving and the temp on the dash matches the temp on the scanner, then noticed the fans weren't turning on when it showed hot, so I plugged both direct to battery unplugging from pcm connectors and they both turn on high, but when on the road at high speeds it shows overheating still, slowing down brings it down but the fans staying on does absolutely nothing to help cool it down, my thought is maybe the pcm is f**** up, please someone point me in the right direction, I can tear this car with my eyes closed now, I've done everything, hybrid battery replacement, tranny oil change, catalytic replacement, water pump etc, I need help with this, thinking of getting the pcm flashed or buying a junk yard pcm and getting it flashed, and help is highly appreciated

 

[ikenewton82]

I don't think it's your pump, if the top is hot and bottom is cold it means the thermo is opening and letting the hot water go to the radiator and is cooling down going back to the engine, had to take it in and they said I had air in the system, they burped it with a machine, it got better but I just too it back yesterday because it stl overheats after driving An hour, it doesn't do it like before but it stl goes up, I don't think they removed all the air, did you seal the thermo housing with gasket maker? I don't like how they didn't make grooves, it's metal to metal on the right side of the housing that can leak if not sealed properly, if you turn on the heater full blast does temp go down? Is it getting hot and staying hot or is it fluctuating to the driving speeds? I'll update when I get my car back today or Monday, this little problem really made me pull my hairs out, there has to be a legit way to burp the air out without a machine, I tried using the bleeder valve above the thermostat housing until water came out and kept adding water till bubbles stopped but I don't think this car behaves like other cars