I have an overheating issue with my Ls/Vtec turbo. I already replace the radiator cap, thermostat but its still overheating. I was wondering what thermostat is supposed to be used for the Ls/vtec. I'm pretty sure its supposed to be an LS one, but just wanted to confirm it. The upper radiator hose is burning hot, and the lower hose is still cold (although sometimes the lower radiator hose gets hot) I'm assuming the thermostat is not opening up, but its brand new (although its an autozone one). any help would be appreciated. Thanks everyone.

 

sounds like you have a bad headgasket

 

I actually just rebuilt the motor. Its a brand new Cometic (3mm) headgasket. and I torqued them down to specification, and had them double checked from my head mechanic. It has to be a regular cooling issue because its not spiking quickly, its a slow/moderate rise in temperature.

 

1st did you burp the system and get all the air out. 2nd are you sure you put the tstat in the right way?

 

3rd... is the fan coming on that you know of? If its not, have you jumped the fan or checked the thermoswitch?

 

Yes, i made sure the thermostat is put in correctly and yes the fan does come on when it is supposed to. I even put the fan up on a switch so that I could control when the fan comes on, but it wont really help if the coolant isnt cycling (the lower radiator hose remains cold). Has anyone had any problems with the water pump possibly not cycling even if coolant isnt coming out of the water pump hole (the little drip hole to check if the pump is still good). I'm gonna flush out the radiator just to check if its clogged (but I doubt it).

 

1 last thing I just thought about if this is in a civic did you increase the size of the radiator to handle the increased heat load of a turbo ls vtec?

 

sounds like the thermostat is not stuck because the fan turns on, so most likely theres something clogged up or wrong with the pump

what head bolts did you use?

 

Yes, i did upgrade the radiator to a Koyo aluminum radiator with a FAL fan. The headbolts are ARP GSR headbolts. Hopefully anyone else has any ideas, cause i'm just about out. I'm gonna try and flush out the radiator today or tomorrow.

 

i have same problem too, my car keep overheat every time i go faster, but when i slow down its goes down, The upper radiator hose is burning hot, and the lower hose is still cold...i just change the thermostat

 

I wanted to thank everyone for their input. Yesterday I flushed out the radiator to make sure its not clogged, and it was working just fine. I then checked out the water pump by pulling out the thermostat, and then undoing the upper radiator hose to check if it was really pumping the water around. That worked just fine. I then checked the thermostat (the new one I bought from autozone) by boiling some water and putting in the thermostat into the water. It opened up just fine. I then decided to cool down the thermostat by pouring cold water over it, and then proceeded to test it again by putting it into the boiling water again. This is when the thermostat didnt open up again. It turns out that the thermostat was sticking and not opening. So I bought me a Honda OEM thermostat from a dealership and now the car works just fine! Not to mention, my buddies car was doing the same thing too at the same time and he too had an autozone thermostat as well. Lesson Learned: DON'T BUY AUTOZONE STUFF, BUY HONDA OEM ONLY!!!!