Honda Civic Journal Logs    

► Air Impact Wrench - Honda Civic
► Bolt and Nut Torque Specifications
► Boot and Front Axle Replacement
► Changing the Engine Oil - Honda Civic
► Changing the Timing Belt - Honda Civic
► Changing the Water Pump - Honda Civic
► Engine Coolant Temp Sensor - Honda
► Fuse and Relay Box - Honda Civic
► General Maintenance Schedule
► Inspecting the Idle Air Control Valve - P0505
► Jerky steering wheel Fix - Honda Civic
► Jump start your car battery - Honda Civic
► Learn to drive stick shift - Honda Civic
► Pass Smog Check - Honda Civic
► Repairing the Alternator - Honda Civic
► Repairing the Brake Pads - Honda Civic
► Repairing the Brake Rotor Disc
► Repairing the Distributor - Honda Civic
► Repairing the Front Hub Bearing
► Repairing the Fuel Filter - Honda Civic
► Repairing the PCV Valve - Honda Civic
► Repairing the Radiator - Honda Civic
► Repairing the Speed Sensor - Honda
► Repairing the Starter - Honda Civic
► Repairing the Thermostat - Honda Civic
► Replacing Exhaust Pipe Gasket
► Replacing Front Rear Shocks - Honda
► Replacing the CYP Sensor - Honda
► Replacing the Fuel Pump - Honda Civic
► Replacing the Oxygen Sensor - Honda
► Saving Gas - Honda Civic
► Stolen Car and Kill Switches - Honda
► Trouble Codes (MIL / CEL) - Honda Civic
► Washing Machine Repair - Bad Motor


Engine Oil ChangeBrake Pad ReplacementBrake Disc Replacement
Axle ReplacementHead Light Bulb ReplacementSide Door Window Replacement
Alternator ReplacementBattery ReplacementTransmission Clutch Replacement
Front Hub Bearing ReplacementStarter ReplacementFuel Filter Replacement

Repairing the Radiator - Honda Civic

I just did a quick check on my timing belts and I suppose they look fine: no tearing or visible signs of issues. However, I did open the hood to a mess of green liquid coolant all over the radiator and fan area.

After no luck in locating the source of the leak, I decided to check if my radiator fan was still working to keep the coolant cool.

Radiator fan still in working condition

My first thought was to ensure that the fan was still functioning. After looking through the service manual to see how the cooling fan was connected, I searched for all locations to the fuses for the fan; none of the fuses were blown. Also, I noticed that a relay was used to control the on/off power to the fan. This can be a good spot to test the fan. So I grabbed my multimeter, set it for measuring current, removed the relay, and started the car. After confirming the female connection points for the fan relay, I measured the current (about 7 amps) and the radiator fan went on. I guess there's nothing wrong with the fan either.

Old and New Engine Coolant Temperature sensor

The last thing I figured was to check the Engine Coolant Sensor (ECT) switch. This sensor was located against the thermostat housing on the left-back side of the engine connected by a wire harness. It acts as a switch and turns on when the coolant in the engine reaches above 80 degrees celsius. This sensor can be tested by boiling water and measuring the ohms for continuity. Since this sensor was relatively inexpensive, I just decided to replace the existing one. But before detaching the wire harness, unscrewing, and pulling it out, I had to make sure I had a pan underneath to catch the coolant that will pour out the hole as soon as it is unscrewed. Once out, I made the replacement and reconnected the wire harness.

Now to test the newly installed sensor. After running the car on idle and pressing on the accelerator to get the engine hot again, I measured the surface of the engine with my multimeter (measures temperature too; very handy) and waited for the radiator fan to come on. Sure enough, the radiator fan turned on. I was hoping this would resolve the problem but the next day after driving it for a half hour, there was coolant splashed everywhere near the radiator.

After cleaning up the mess without any luck locating the source of the leak, the next day, I left for the local auto store for some simple solutions.

The 1st thing that caught my eye was a green bottle that was labeled 'stop leak' for radiators. Reading the simple instructions convinced me to try it out.

The label instructed to pour the contents of the thick yellowish liquid through the radiator cap opening. Then topping it off with more coolant and running the auto on idle for several minutes.

Minutes later, I inspected the radiator, it seemed to have reduced the leak to some degree. I could now see where the leak was located! There appears to be a half inch crack below the radiator cap area. The next day I drove it for an hour or so hoping the substance would plug the crack and stop the leak once and for all.

The leak didn't completely stop so I decided to try another brand. This time it was a bluish color with a label that provides relatively the same instructions. I performed them again and turned out it didn't help much either. If anything, it appeared to have gotten worse. Now the crack appears to have extended an inch or so longer.

so I tried a new unexpensive approach; patch it up directly with some radiator sealant. The sealant I stumbled on contained a black and clear mix that would form the sealant over fiberglass fabric. As I followed the instructions, I applied the paste and fabric to the crack and later allowed it to cure long enough to harden.

It appeared to be successful but after running the auto around for an hour, the coolant somehow found a way around the patch and began to leak again. So small yet so troublesome.

I guess I had no choice; time to buy a new radiator. The next day I left for the nearest auto store with the right radiator in stock and began another project that hopefully would be the last.

New radiator

Surprisingly, at least for me, the radiator was extremely light. However, the hundreds of aluminum walls on the radiator were easily bendable. I needed to be careful during installation to reduce any damage to the radiator that may affect it's efficiency to cool down the coolant.

Here's what I did to repair:

The first objective was to cool and drain the coolant out of the radiator. To easily reach the drain plug from the hood, removing the radiator fan helped a lot.

1. Disconnected the battery. not that I'll be working close to too many electrical components, but it's good extra measure and since I had 3 hours before bed time, why not?

2. Let the radiator cool down.

3. Carefully removed the radiator cap. Used a hand towel to protect me from any remaining harmful steam

4. Removed the overflow tank and the small hose connected near the radiator cap.

5. Disconnected the wire harness to the radiator fan.

6. Unbolted 4 screws from the radiator fan

7. Removed the radiator fan

8. Placed a drain pan underneath the radiator drain plug. (adjusted the position of the drain pan as the coolant poured out)

9. Untwisted and removed the drain plug. Allowed all the coolant to drain out of the radiator.

10. Removed the remaining top and bottom hose connected to the radiator.

11. Unbolted the top radiator bracket securing the radiator.

12. Removed the old radiator.

13. Placed the rubber feet pads from old radiator to the new radiator.

14. Cleaned and removed any debris from the area for the new radiator

15. Installed the new radiator.

16. Worked my way backwards and reinstalled all the bolts, hoses, and wire harness.

Nice new radiator installed

Beautiful! Perfect fit and was not a very difficult task at all. Now to fill the radiator and overflow tank with coolant. I drove the car for about an hour and looks like the overflow tank had become empty. I figured that another refill to the overflow tank should be the last - hopefully i'm right.

After 2 days of driving, i'm happy to report that my radiator problem is over :)

Radiator ReplacementCost (2007)
Autoshop (Parts & Labor)$
Do It Myself (Parts)$

Saved$ (%)

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