I have a honda accord 1991 car is overheating engine light came on once and car doesnt overheat when i have the heater on do u think its a fan i changed the thermostat and flushed the radiator
The fan is electric. The fact that turning on the heater helps is a good indicator that the cooling system isn't sufficient but there are a lot of things to try.
The fan shouldn't come on very much, but it is easy to see if it is working OK. When the temperature gets above where it should be, open the hood and see if the fan is running. If it is, it is not the fan or the thermostatic fan switch. If it is not, the most likely cause is the fan-switch that is screwed into the bottom of the radiator. be carful when removing and replacing as the place they screw into the radiator may be plastic.
Assuming the fan does come on when the temperature is going up, the most likely cause is a radiator with poor flow,
be sure to check the simple things first. Is the coolant recovery tank at the proper level?
Are you loosing any coolant?
If coolant keeps disappearing, you either have a leak in the radiator or hoses or heater core or ... you have a bad head gasket or cracked head. A compression test will tell you if it is one these "bad" things, but do that last. A cooling system pressure test will tell you if you have a system leak, but not where it is. Do that after you check and do all the simple things, and if you are not losing any coolant, and the recovery tank is staying at the proper level, a leak is less likely. Sometimes with a blown head gasket, engine compression will force air into the cooling system. If that is what is going on, you should be able to open the coolant recovery tank when the engine is running but leave the hose that is connected to the lid down in the recovery tank coolant. Look for air bubles coming from the bottom of the hose or oil in the coolant recovery tank. If you see either of these, then head gasket or cracked head is likely.
If the fan is working and the coolant level in the recovery tank is staying where it should, the most likely cause is a plugged up radiator. Even flushing with a radiator flush may not help, and the radiator will likely need to be replaced. Replacing the radiator is not a very big job and after-market radiators are quite reasonable for a 91 civic from most autoparts stores or on-line, but if you haven't done one before, get someone to help you or at least get a repair manual.
When you flushed the radiator, did you bleed the cooling system? There is a bleed valve located near the front of the engine and toward the passenger side. It opens with a 10 mm. wrench. The valve is located at the top of the cooling system and it is to get all the trapped air out of the system after it has been opened or flushed. It helps to raise the front wheel on the passenger side, then open the valve and let all the air out. When you get a solid stream of antifreeze with no air, the system is bled.
The most important thing is don't just start replacing things. Find out what's wrong, then fix that. Otherwise you could spend a lot of money and still have the problem.
I hope it is something cheap and simple - it is more often than not.
Oct 01, 2010 |
1991 Honda Accord