Ok so I'm having problem with 2003 Civic Ex. It's been leaking coolant, it seemed the radiator was bad so I replaced it. All the hoses were fine. So I drove it ling distance and everything was till the other day it started to over heat, the needle would start to up then go down(temp gauge). So I immediately shut it off and it leaked water again. What could it be?

 

mileage? water pump maybe?

 

105,XXX

 

Oh btw it's leaking by the radiator down by The lower hose. Could it be thermostat?

 

The thermostat is on the engine block, so it shouldn't be the direct cause. Have you tried replacing the lower hose clamp? It could be worn out from the removal/installation.

 

Does the radiator fan come on at all?

Did you bleed the system to relieve it of air bubbles after replacing the radiator?

Is the hose leaking, or is it coming from the thermostat housing and dribbling down the hose?

If it's coming out of your coolant reservoir (the white plastic bottle next to the radiator) you likely have a blown head gasket. (which would also explain why your car is overheating)

 

And it only over heats on the streets on the freeway it's fine. How do I check if the fan still works? And no it's not coming from the reservoir tank. And if I had a head gasket blown wouldn't I also leak oil around the outside of the head?

 

Go to your local Advance autoparts store and get their cooling system pressure tester loaner tool and test the system it will show where your leak is coming from.

 

Many people experience this when their head gasket is blown. (but that's not the only possible reason that your car is getting hot)

Open the hood while the car is warm/hot and watch it. You should also be able to hear it activate while the vehicle is stopped. Or else you can unplug it and run 12v and ground to it, and it should run. If it does not run, replace it.

That's a plus.

No. Nor will you necessarily see coolant in the oil. The gasket can be bad without the coolant and oil mixing together.