I had an over-heat event in May. The coolant was very low. I found a plastic crack in the radiator near the cap. I replaced the radiator and found no other coolant leaks. The coolant and oil both look good, they're not mixing.
Here's a list of symptoms: - Uses about a quart of coolant per 50 miles but I can't find any leaks - Bubbles in the radiator overflow at operating temp - The radiator overflow only gets more and more full, the coolant never seems to go back into the radiator. - Radiator over flow gets full and I have to remove coolant from it - Code for random cylinder misfire - Dead miss on at least one cylinder for about 5 or 10 seconds after startup if the engine hasn't run in 30 or so minutes but then smooth with good power - Compression test results (Cylinder/PSI): - 1/180 - 2/130 - 3/180 - 4/175 - 5/175 - 6/180 - All spark plugs are dry except 6 which is wet
Because of all the air in the radiator whenever it's driven long enough to heat up I think it's combustion gasses. Is there any other way for air to enter the radiator? I don't have a radiator pressure test kit. I was surprised that the cylinder compression test readings where so high. Is there anything else I should look for before pulling the heads off?