Hello,
I have a 1998 Honda Accord 4cyl Sedan. I had the radiator changed as coolant was leaking from the top of the radiator in May 2012. Everything was working fine until now.
Since 2 months I saw a white smoke coming from the AC vents inside when I turned on the AC. I did not know what to make of it. AC was working fine and I did not do anything.
Yesterday, AC was not cooling and the engine heater gauge went all the way up. So, I turned off the AC and drove for 0.5 miles and parked the car at my house. Today I saw that the coolant reservoir is empty. I do not see any obvious leaks.
I am guessing that the white smoke was coolant as it smelled different.
How do I fix this.
Any help is greatly appreciated.

 

With the car sufficiently cooled down, refill both the radiator and the reservoir with the proper mix of coolant/water (some are pre-mixed).

With the ignition switched to ON (II), turn on the A/C. Check that both cooling fans (A/C condenser fan and radiator fan) turn on and run strongly. Let us know what you find.

 

I filled coolant reservoir and the radiator with the 50/50 premix. With the key in position II and AC turned on both the fans run strongly.

I was surprised by the amount of fluid I put in the radiator. I bought a gallon bottle and used more than 1/2 of it to fill the reservoir and radiator.

 

You might want to bleed any air out of the system but we'll save that for later. Need to figure out where the leak in the cooling system is.

Start the car, ac off, temp **** to max heat, blower motor off. Check for leaks, keep an eye on the temp gauge.

 

After running the car in idle for 20min, I saw smoke coming from the radiator from area under the radiator cap. Not from the cap itself- I don't think the cap is leaking as the smoke is coming from far below it. The temp guage was 1/3 way up. Both the fans did not turn on during the whole time.

 

It is a little smoke or a lot? Could it be residual coolant burning off or is it coming out a specific area?

Feel the lower radiator hose, does it get hot? If not, the thermostat may not have fully opened. The thermostat should be fully open at 194 degrees F. If it does not fully open at 194 F, it may be a bad thermostat. Rev the car a little to try to help get the coolant temp. up a little to see if that will open the thermostat.

Above 199 degrees F, the radiator fan switch (a normally open switch) should close and turn on the cooling fans. Fans not turning on above 199 F may indicate the fan switch is faulty. Just to ensure the circuit leading from the fan switch connector is okay, disconnect the green connector at the radiator fan switch and use a small paper clip or wire and jumper the green connector plug. Turn the ignition to ON, does both fans run? If the fan runs like that; but, still doesn't turn on when the plug is connected back to the switch and the coolant temp. is above 199 F, then the switch may be bad.

Generally, with a properly working cooling system, the thermostat should be fully open before the cooling fans turn on.

 

Was there smoke coming out of the HVAC vents inside the car? If there is smoke coming out of those vents and none under the hood I would look toward the heater core as the culprit.

I've never done this but have heard of people who drained out their entire cooling system then performed a smoke down test to find the leak...

 

I turned car on idle for 15min and the temp gauge was 1/3 up. I did not see any smoke from under the radiator cap this time.
The lower radiator hose (the one at the bottom of the radiator which is mostly rubber) was hot.
Both the fans turned on for 1-2 min and then turned off. Because they turned on by themselves, I did not jump the green radiator fan switch.
First time around, I went into my house briefly and the fans may have turned on at that time.
Is there a photograph of 1998 Honda accord labeling different parts, so I know I am doing the right things.

 

Thermostat and cooling fans sounds like they are working.

Attached is a diagram of the fan controls.

I already include the picture of the radiator fan switch in my other post above, where the thermostat housing is.

Sound like you're looking at the right things. Just have to observe whether the coolant level will still be dropping and make sure car doesn't overheat.

 

Thanks for your help.
Should I drive the car and keep an eye on the coolant level and temperature gauge.