D17A1 overheating, mysterious coolant loss, bubbles in overflow...
 

Following is a useful summary of my recent experience with a 2002 Honda Civic LX, auto trans, 1.7-liter engine with 185,000 miles:

Typical Symptoms:

1. Engine overheating (as indicated by dash gauge).

2. Mysterious loss of coolant from the radiator (with no visible external leaks).

3. Overfilled coolant reservoir.

4. A stream of small bubbles in the coolant reservoir and/or radiator (with the engine running).

5. Excess pressure inside coolant reservoir.

6. Exhaust gas inside the radiator filler neck area (cooling system fails block test).

7. Gurgling sound from the cooling system immediately after shutting down a warm engine.

8. Small amounts of engine oil in the coolant.

9. Coolant mixing with engine oil (milkshake-like appearance under oil cap on valve cover).

Likely Causes:

1. WARPED CYLINDER HEAD that resulted from engine overheating, and/or

2. Blown head gasket.

Allowing combustion chamber gasses to leak into the cooling system (creating excess pressure in the coolant reservoir) and/or coolant to leak into the combustion chambers and get vaporized (lost out the exhaust pipe).

Recommended Solutions for success:

1. Use OEM (Honda) parts exclusively

2. Follow the OEM (Honda) service manual TO THE LETTER.

Happy Wrenching! :-)

"4. A stream of small bubbles in the coolant reservoir and/or radiator (with the engine running).

5. Excess pressure inside coolant reservoir."

Good indication of headgasket issue, hope nothing crack..

-----------------
Based on my experience, head gaskets are frequently improperly blamed for this problem. In my case, cylinder head warpage was causing the leak NOT a blown head gasket.
The cylinder head flatness MUST BE carefully measured with a machinist's straight edge.
The OEM (Honda) service manual MUST BE followed closely to avoid wasting time & money!

Hi !!

I have a car just like yours !!....Antifreeze bubbles coming off the reservoir, and reservoir spilling. Radiator getting low in antifreeze and no heat idle. BUT so far, i have no oil color in reservoir, no white gummy things in the oil.

Of what you know now and experience. Would it still be a warp cylinder head gasket?

Mario, Nova Scotia, Canada.... Milage...150,000 miles