NorPlan

. 2002 Honda Civic 1.7L.. I believe the Thermostat is acting up ?? Going down the Road Highway Speeds the Heat is Satisfactory.. Come to a Red Light where the RPM's drop idling the Heater starts to Blow cool air after idling a few minutes. Would we be correct in believing the Thermostat is not opening up properly ?? Would it be a difficult job to Replace the Thermostat if that is the Problem ?? Cheers Thanks.

Falloutkid90

Its not hard to do but i have the same problem and i replaced mine (unless the new one was broken)

NorPlan

@Falloutkid90... You say Same Problem loosing Heat at Idle ?? Now Did Replacing the Thermostat solve the Problem ??

Falloutkid90

Yes nice hot heat when im driving the it drops to cold at a stop light. I went to the store and picked up a thermostat and replaced it. It still does the same thing. My car is at 109k so i need to do the water pump and timing belt so im wondering if it could be that or maybe i need the coolant flushed because the heater core is clogged. Idk ive been trying to figure it out for weeks but it keeps leading back to either the thermostat water pump or radiator fan sensor switch.

Rick hybrid

less heat at idle because the water pump is not spinning as fast.
also check the coolant level, if it is is low you'll also get less heat.

Falloutkid90

So the water pump is on its way out? If thats the case it good that im going to get it replaced. Coolant is full.

xclusivedanny1

the 01-05 honda civic 1.7 liter motors are known to have over heating issues

MCHAccordLX

I had this issue last winter when I first got my Civic. I hate to be the bearer of bad news, but these cars are known for their head gasket issues. The dealership I bought mine from replaced the head gasket for free, and at the same time I paid for them to do the timing belt and water pump. When I brought my car in for the airbag recall to a Honda dealership near my work, turns out that's where it was having all of it's regular service done. The previous owner had brought it there for an issue with no heat and overheating just before they traded it in to the dealership I bought it from.
It only makes sense to try the easy/cheap fixes though first. I've heard that it's best to just buy the thermostat from Honda. Apparently these cars have a really finicky cooling system, it's best just to give them what they want. Most dealerships will price match places like Majestic Honda, etc.
Mine still doesn't seem to be fixed all the way, so I'm probably going to try putting in a new thermostat and radiator cap on mine since I'm sure that wasn't done.

NorPlan

@MCHAccordLX.... Being that the Car is a 2002 Civic Sedan.. First Time Thermostat Housing was Removed, Hence a stud was snapped..lol.. Brought the Car to a Friend with all the right tools to remove broken stud , New Bolts & Thermostat.. All is Good , Lots of Heat , No Heat Loss..lol...