I have a 00 Integra GSR w/ I/H/E. I recently replaced the head gasket, flushed the coolant system and replaced the thermostat. The car is overheating, but not to the point of getting all the way to H. The fans are not coming on even when it starts to overheat. I checked the fuses and they are okay. It seems like if I rev the motor up the temp starts to dip down, but then at idle it begins to rise again. After I got it back home I could hear a bubling sound in the hoses, but it was not bubbling out into the overflow tank. I let it cool, took the cap off and refilled it, but it still starts to overheat. Could this just be the fan switch, or something else? Any input is welcome. Thanks

 

Try bleeding all the air out of the system. If there's an air pocket in there it will block your T-stat. That's what the bubbling noise is.

 

I had the same problem. I replaced the thermostat and it worked fine after that.

 

I had the same problem. I had a bubble in the coolant. Two steps. Reset the ECU(or just disconnect your battery and reconnect-it helped me fix it). Bleed your coolant. You don't need to flush everything out like a lot of people say. Just let your car cool off and then fill up your coolant fluid. Then open up the radiator cap (the one that says don't touch- well open that one). Make sure you use a towel to open/close the radiator cap at all times. Turn on the engine and let it warm up on its own to running temperature for 10-15. Then close the radiator cap. Turn off your engine and let it cool back down for 2 hours. Then pop the hood, open the cap, and let it run again for a good 10 - 15 minutes. Turn it off, put back on the cap, and take it for a spin on the freeway. Your problem should be fixed. When you get back, check that its not over heating at idle. Your coolant level should be almost empty. Fill it back up. You should be good to go. It fixed it for me when I cleaned my IACV and it started over heating. Good luck.

 

PS: your coolant is probably backing up from air bubble(s). The coolant can not properly flow through the tubes, which is why you want to open the cap...to let the bubble(s) slowly work their way out, ridding of the "back-up" of coolant in the lines. That's why you most likely will need to re-fill the coolant back up again.

 

Thanks for the responses, I will bleed the air out of the system, but my next question is would this keep the fans from coming on, or do I need a new switch?

 

No. With the coolant properly flowing your fans should begin working correctly again. I had the same problem and it worked for me

 

Alright so i bled all of the air out of the system and the fans come on now, but the car starts to overheat once I turn the interior heat off, and once I turn the heat back on the temperature starts to drop. I don't know what's causing this.
I think it is either the head gasket or water pump. When I pulled the valve cover there was no milky substance on the bottom of it, like the first time I blew a head gasket. So what could my issue be?
- Any suggestions are welcome.

 

Anybody...

 

thermostat maybe not opening correctly not letting the fluid flow through to cool it off, since you bled the system i would try that next

 

OK, so I replaced the thermostat with an OEM Honda T-stat and the car still overheats. I don't think the t-stat is opening because the lower hose is cold while the upper hose is blazingly hot. Also the fans never get switched on. I know they work because I jumped it to make sure. So I don't think the thermostat is opening, but I don't know why. I took it to a shop and they said the waterpump is working, so what could it be? I was gonna get a new rad cap, and flush the system again. Otherwise I'm at a loss and it's driving me crazy.
Any help is appreciated.

 

Replace your temperature sending unit, its a small plug next to the thermostat. I have had a similar problem and this was the solution I came up with after replacing the fan relay and thermostat

 

-So the fan kicks on if there's no t-stat, so I know it's not the switch.
-After replacing the rad cap and flushing the system again, the car still over heats. I've noticed that every time after letting the car cool the car lows white smoke, so I'm thinking it might be the head gasket.
-Also it really only over heats with load on the engine and only after about 10-15 minutes of driving. After I get it home I can leave it running with the heat on for 30 minutes easy without it over heating. But ever since I put the t-stat back in the fans don't really kick on.
-My only other idea is to replace the water pump.
- Any other ideas anybody?

 

Where did you buy the T stat? What's the temp. rating on it?

 

Acura dealership. 78 degrees Celsius

 

^^^

 

Are you filling up with anti freeze or coolant, or the 50/50 mix? Are you constantly filling it up? May have a leak somewhere, or you have a bad/hotter thermastat. I believe you can buy a cooler one if that is the case...

 

if the top coolant line off the thermost is pressurized then your t-stat is working. you may have a faulty radiator that is just circulating hot coolant throughout your gallies. youve done a good job brainstorming and going thru other things but id check that out.

 

You mentioned that you blew a head gasket. Why did this happen? If the car overheated severely you may have warped the block and/or head. If this is the case replacing just the gasket may not be enough. Since you mentioned white smoke, you still have a head gasket problem. When you stalled the gasket did you check the head and block for flatness? Did you thoroughly clean the head, block and gasket before installation? Did you use new head bolts or new head studs?

 

Could it be the temp. sensor? Could it not be giving out the right temperate readings causing the fans to not come on? Once the fans come on the car should keep itself cool when it reaches a certain temp. I had a similar problem with my teg after i swapped it; the upper hose was extremely hot and the lower hose was ice cold, I just drove it like that for a couple months and everything started to work fine.

 

Yea that's what I was afraid of. I did thoroughly clean the head and block and used new ARP studs. I did not do a flatness test because I only overheated once before doing the head gasket, but I guess I was wrong. So I'm gonna pull the head again to get it checked out, and while I do I'm going to replace the water pump while I'm at it. Thanks guys you've been a lot of help, and now I'm off to pull the head again.