Civic Coolant Problem

First off, I love the Car Talk show and listen to it every Saturday.

I have a 2002 Honda Civic 4 door LX with automatic transmission and a 4 cylinder engine, the car has about 112,000 miles on it and I am the original owner. I consider myself an amateur mechanic at best but like to tinker around, especially with the advent of the internet there is no shortage of information available at your finger tips. 3 months ago I executed a full tune up which it took me a couple of nights working in my friends garage after work but I managed to successfully replace the following components and fluids.

? Timing belt

? Auto tensioner for timing belt

? lower timing belt cover and gasket

? Oil seal crankshaft & camshaft

? Water pump

? Alternator belt

? Power steering pump/AC compressor belt

? Radiator bottom hose, top hose, and hose connection between radiator and reservoir tank

? Radiator system flush & bleed

? Valve adjustment check, no adjustment needed

? Power steering fluid flush

? Brake system bleed / flush

? Clutch system bleed / flush

? New gasket on valve cover

? spark plugs

? air filter

This is also the first time the coolant has been changed. All parts were purchased from the Honda dealership. I used hose clamps with the thread and bolt tightener purchased at a hardware store.

The problem that started happening is that the car is overheating. When I checked the coolant level I found the coolant was being forced out of the reserve tank. I took the car to the dealership who told me it was not bled properly and that the radiator cap needed to be replaced. I paid them for the service but the problem persists. It seems that air is getting into the coolant system somehow and is pushing the coolant out through the reservoir tank so I have to bleed the system about once every week or 2. My wife and I don?t do extensive driving in it but we did manage to take the car from Atlanta, GA to Sarasota, FL where I needed to execute a coolant bleed and then again after we had made it back to Atlanta so it seems the bleed is very slow.

I believe the thermostat is working correctly as the hoses seem to be at the correct temperature when the engine is cold and also when it is hot.

No white smoke is coming from the exhaust so I don?t think I have a blown head gasket either but I believe if that were the case the coolant would be disappearing not being displaced.

Any help you can provide would be very much appreciated.

Thank you in advance,


I may have some bad news for you. If the coolant system was not bled properly the first time, you may have damaged the head gasket when it overheated. Now, combustion gases are being forced into the cooling system, and that’s what you are bleeding out. It sounds like your on the brink of a fully blown out head gasket. Check your oil for any coolant contamination. If the oil looks like brown cream, you have coolant mixing with the oil, and this could lead to damage to the bearings. A compression check may also reveal a break in the head gasket.

Was the thermostat replaced? The 'stat has to be installed with the jiggle pin up so that the engine block will vent on coolant refill.

Does the temperature gage show the overheat condition, or is the only evidence of “overheating” in the reserve tank?

With the engine cold, the radiator will be full of coolant. As the system warms up while the car is driven, the coolant expands into the overflow tank. With the system cold, there will be a small volume of coolant in the reserve tank. With the system warmed up the reserve tank will contain more coolant, but it should not be full.

Does the “coolant bleed” mean that you remove coolant from the reserve tank?

First, check the engine oil as BustedKnuckles recommended, to be sure a major failure has not happened. Then, if the oil is clear…

With the the engine cold, remove the radiator cap and fill the radiator with coolant if it is not already full. Next, remove coolant from the reserve tank down to the MIN level. After the car is thoroughly warmed up, check the coolant level in the reserve tank. It will have risen, due to coolant expansion (about 6% over a temp range from below freezing to boiling). The coolant rise & fall happens each time the car warms up and cools down.