View Full Version : To much Antifreez

03-15-09, 08:58 PM
Nice day today and decided to change my oil and coolant. Looked in the FSM and followed the directions by removing the wind shield....then looking for the radiator drain cock. Guess they have a different term, turned out to be a plastic plug that gets removed. Anyway, let it all drain out and noticed the bottom of the radiator seemed to be a low point. Went to fill it, put in a gallon of the Prestone GM approved antifreeze and had calculated I needed two and a half gallons for the system to get a 50/50 mix. After starting the second gallon it filled up. Went ahead and burped the engine and it never went down. Do I have a problem with the ratio causing any problems. I took the car out to do the burping and saw no difference in the temperature readings. I know I can take it to the dealer and have them do a coolant flush, but is that necessary?

If I hadn't already put the wind shield back on before starting to fill i, so didn't really want to crawl back under to drain again. At 71 you count the number of times you lay down on your back and then get up.

Any advice on the consentration or antifreeze ratio and any damage it might cause would be appreciated.


03-15-09, 10:27 PM
Not to worry. If you have too much DexCool in the mix, all you have done is given up a few degrees of freeze protection and a few degrees of boil protection.

Buy an antifeeze tester from an aftermarket parts store. Carefully measure xx oz. of your 100% DexCool with the same number of oz. of water in a small container. Measure the concentration with your new antifreeze tester and note the reading. You now have a calibrated antifreeze tester for a 50/50 mixture.

Test the antifreeze mixture in your engine at the reservoir. To adjust the mixture in your engine, with the engine cold, remove the radiator hose from the thermostat fitting (be sure to capture the toxic spillage). This will allow approximately one qt. of coolant to escape. Make the appropriate adjustment with water or 100% DexCool as required.

Warm the engine to operating temperature and allow to cool. Test the mixture at the reservoir and repeat the process until you are satisfied with the mix ratio.

Possibly a time consuming process but you will not have to get under the car again!

03-16-09, 10:16 AM
Ray, also worth noting is that the FSM states that there will be about 2qts. of residual coolant that cannot be removed from the block which would explain why your calculations where off.