I really need some help! i drive a 99 model Honda Civic 150 Turbo...
Stock internals 500cc injectors, Dictator fuel management, Bigger Radiator, Intercooler and T28 Garret Turbo!
for the past few weeks i had a overheating problem the Temp guage doesnt go over Half, But the filler bottle boils over..... Note Only on Boost does this happen!
I took it to JDM Tunning and they were convinced it was a blown head gaskest. the head gaskest appeared to be fine so replaced it anyway as well as the thermostat... Car went on the Dyno and was re tunned as they said it could be a tunning problem too!
I am only running 0.7 boost so its not much at all! the radiator is practically brand new the mod was only done 8 months back car was just serviced now by JDM! Please guys help me i have just spent R13000 to on and dont want to waste more money on maybe its this maybe its that!
There is no Oil loss nor water loss Thermostat is brand new Water Pump seems fine What can it be and why would it Boil in the Filler bottle under Boost only???

Thanks Guys

 

If you have boiling in the bottle it has to be boiling in the radiator as well, perhaps you have an air lock/pocket in the system.

I know a corvette will boil if you get an air pocket, this happens quite a bit after changing coolant, the fix is to vent they system as coolant is added.

Try refilling your system with the highest hose on the system open to vent the air pockets.

 

first off, welcome to honda tech, second, wrong forum, thirdly, you might have a air pockets in your cooling system. run the car with the rad cap off and let the cooling system burp out all the bubbles.

hope this helps you