i installed a jdm itr 4-1 replica header and now the engine will not get up to normal operating temperature. it is running at about 1/4 temperature gauge on the freeway. i replaced the thermostat last month and car was running great with needle about 2 notch under the middle of the gauge. now since temperature is too cool, vtec is not engaging. Honda-tech please chime in, every comment is appreciated.

 

Does the car actually not get up to temp, or does the gauge tell you it isn't getting up to temp?

 

The header shouldnt have anything to do with it. There has to be more to the story. Replacing a smaller header with a bigger header should create a lean condition which will create more heat in the exhaust due to more oxygen content inside the header (a bigger fire is hotter than a smaller fire) If Vtec doesn't work you more than likely have cel and thats where you should start. Did the car even get up to temp before you tried Vtec?

 

well today i took the car out all day and it seems that vtec does work and i say this only because it still makes power to the top however there is nothing to differentiate between the noise at the 4400 crossover, the cross over was very noticeable before i swapped the 4-1 itr replica header on. i still can not figure out why the gauge does not get up to normal operating temperature anymore and always sit halfway to the middle, what do you guys think? could a small header leak cause low operating temperature? please chime in. if all i can't figure this out i will put my stock header back.

 

anyone?

 

Is the guage or sensor broken? A header leak won't affect coolant temp. which is what the guage reads.