My 2003 Honda Civic ex has been having overheating problems for the last couple of months. I have brought it to mechanics five times and they are stumped. They have already replaced the thermostat, radiator, and a fan that was fried. They have tested it for hours but still cannot find the problem. The car has 257,000 miles on it and it runs fine for the first 2 hours and then I will notice some fluid on the ground from the front passenger side and shortly thereafter the car will overheat. I also noticed that when the car is overheating the heater will blow cold air. The mechanics said that they have also checked for blockage in the heater core and water pump. Any suggestions???
Overheating & Coolant System Problems on 2003 Honda Civic
Hey I had the same issue. I mostly got the head gasket answer. but it turned out it was a bad Radiator Cap. especially cus I also needed a new radiator. so maybe try that before all the head gasket and scary (expensive)stuff
I would have the garage do what is called a "block check" . The cooling system is tested for the presence of Carbon Monoxide. Carbon Monoxide is a by product of combustion and the only way carbon mooxide can be present in the cooling system is if the cylinder head gasket is failing or the cylinder head is cracked. There are several types of test testers, they draw gasses from the cooling system through a chemical, if the chemical stays blue in color, there is no headgasket problem ,if it turns green or yellow there is carbon monoxide present and the head gasket is failing. Snap on and Matco sell them from the tool truck they are relatively inexpensive. I have seen them online for $60 but don't have the part number here with me right now.
Your problem is likely to be the head gasket needs to be replaced. If you can take the car back to the shop and have them do a cylinder compression check, if there is low compression you will likely have to get rid of the car. The reason I'm thinking this is that the heater in my 2003 honda civic ex would not blow heat when stopped or at low engine speeds. When the cooling system was checked the system was low on coolant, some of the coolant was evaporating out of the radiator cap, and the rest was working its way through the head gasket into the engine causing a ton of damage to the affected cylinder. One other thing to check to see if water of coolant is present in the engine oil. I hope this helps.