I tryed searching, but couldn't really find any help. I have a 94 si.. had some problems about a month ago and blew the engine. It is my only car and had a d15 block so I used that with the 1.6 vtec head. Everything seemed to run great, but I did have a code 6. The temp gauge seemed to work fine adn the car didn't overheat, and the car worked, so it wasn't my top priority at the time.. so yesterday the car started to overheat. It would do it after driving it pretty good and getting into some boost. It would go about 3/4 up and maybe a little higher twice. It would eventually come back down if I just drove normally. It doesn't seem to even get to half way when the car is just sitting after I start it cold. Only after I drive it it tends to get hot. So I took the Coolant Temp Sensor off my old 1.6 and swapped it to the 1.5 and it still does the same thing and I still get the code. I did reset the ECU aswell. The coolant temp sensor is the 2 prong sensor that connects to that 'elbow' where the thermostat is, correct? Just making sure I did infact replace the correct one. My coolant was going into the overflow as well.. pretty much filled it up. At first I thought it was the head gasket so I did a leak down and everything came back perfect. So I don't think that could be the problem. This all started when it got 80+ degrees outside so I am figuring that's why it is overheating all of a sudden. If anyone could lend me some insite to this problem I would greatly appreciate it. Thanks a lot!

 

don't know about the code 6 issue, but about your overheating... check your fan bolt. It may have came loose and your fan might not be connected to your fan motor anymore. this happend to 2 EG's that i know of. good luck bro

 

Forgot to mention that the fan does come on.. It did atleast when I let it sit and idle.. Could it possibly be air in my coolant system? when I filled it up earlier after changing that sensor I let it idle for like 10 minutes without the cap and there were bubbles of air coming out.. but then it started to overflow and I had to cap it off..