2003 Civic Si 2 Door Coupe - heating problems
 

Hi everyone! This is my first post, i appreciate all the feedback. I have a 2003 Honda Civic as listed above but am having a problem that no mechanic or honda dealer in my area can seem to fix. My car takes a very long time to heat up. I can start the car in the winter, and it will never fully heat up until i start driving. While driving, the heat is fine, not nearly as hot as it used to be, but still heats up to the normal section. If i stop in a driveway or on the side of the road, and put the car in park and let in run in idle, the temperature gauge will start to drop and it will start blowing out cooler air. Once i start driving again, the temperature gauge will start to rise again and start to blow out warm (not hot) air. It is just very frustrating in the winter when you dont have a good heat source for your car.

One other note, while driving, i must leave the blower on the 1st second or third setting to heat up, if i turn the blower dial all the way up, it will not heat up fully. I hope someone can help. Thank you.

Re: 2003 Civic Si 2 Door Coupe - heating problems
 

Remove both heater hoses and look for something blocking one of them. Somewhere in the cooling system, there's something blocking flow, this happens quite frequently, but not so much on Hondas. I get a lot of Mitsubishis where the thermostat gasket will break off and get stuck in a heater hose which will cause the heater to only work above 2500rpm after about 10 mintues of driving, but once the RPMs drop, the heater blows cold.

Re: 2003 Civic Si 2 Door Coupe - heating problems
 

hey man.. small world cuz i just had the same problem. its ur head gasket. i have an 02 si and that same problem was going on with mine for about 3 weeks n then one night my temp gauge was spiking. so go get it checked cuz if u let it overheat theres a chance ur head will warp n then u gotta get a new head