After paying a shop to "flush" my cooling system I was not thrilled with how it looked when I opened the cap on the overflow tank. I decided to buy some Coolant flush and clean it more. I followed the directions and drove about 3 hours over 2 days and then drained the radiator. Filled with water, ran engine and heat and drained again. Did this about 4 times to make sure I was getting most of the stuff out. When I felt I was done I added 1 gallon of anti-freeze and 1 gallon of distilled water. Drover around and then let it sit overnight last night thinking I would need to add more coolant. To my surprise it was still ner the cold level.

Tonight I let the engine run for about 15+ minutes with heat on and off and the overflow tank cap off thinking there might be air in the system. Closed the tank up and drove a couple of miles. Popped hood and took off cap and did not have much pressure. Let it idle, drove a little and now waiting until tomorrow morning to see if level goes down.

My question is could air be in the system? I thought letting it run with the cap off would remove all the air. Also, seems that only adding 2 gallons is not nearly the capacity. The coolant in the tank seems much cleaner leading me to believe I got most of the old stuff but it still seems like I should have added another 1 - 2 gallons of coolant/distilled water. WE are going on a camping trip Thursday and towing a pop up so don't want to get into the trip and have it overheat. The driving I did tonight was idling for 20+ minutes and a few miles and it stayed at normal temp. thanks

 

The engine was already filled with straight water from the flushing. What you should've done was add two gallons of antifreeze and no more water. The two gallons of AF mixed with the approximate two gallons of water already in the system would've given you the 50/50 mix required. Now you've got a 25/75 mix and are at risk of boil-overs or freeze ups. At this point I think you're stuck draining it back down and adding two gallons of AF back in to protect yourself.

 

Thanks Alloro. Question. The term "flush" might be overused. I'm not sure if I actually flushed since I did not add any type of special flush kit nor did I take off any hoses or t-stats. My method was simply opening the peacock, draining the radiator, filling it back up and letting engine warm up and doing this about 4-5 times. Is it safe to assume that I still have some old antifreeze in the system before I added the 1 gallon of antifreeze and actually 3/4 gallon of distilled. I rounded this up to 1 but it only took 3/4 of a gallon of distilled. I also always remember you are better off with a lower % of anitifreeze than a higher % if you are in a situation like this. Certainly 75/25 is not good but what about 60/40? Thanks

 

we didnt really answer the main question. that question was how do you get air out of the system? i hear running water when i accelarete and goes away at idle. any ideas?

 

Yes 60/40 is good. If you don't want to drain it again, the best thing you could do is test the strength of the coolant. Your local hardware or auto parts store should have the testers. They're not that expensive. Here are some just in case you don't know what they look like.
antifreeze tester - Google Product Search

 

Drive the front wheels up on ramps, park facing up a steep hill, or jack up the front end and put it on jack stands. Run the engine up to operating temperature, turn the heat up to hot, and rev the engine up to about 1700 RPMS. Hold it there like that for about 10 minutes and most, if not all of the air will be out.

 

Thanks Alloro I'll do that now or in the morning. Question. Do you keep the system fully closed or do you keep the top off the overflow tank. BTW, I have an '00 Expedition. tks

 

It doesn't matter with these types of systems. If there was a radiator cap, then the cap would have to be left off to allow the air to escape. In your case, just make sure there's always coolant in the bottle as the air is burped out of the system.

 

Thnaks for the reminder. Had one of these in my basement. Pulled it out and did a test. The reading was at the bottom end of the guage for protection. This was not good so I flushed the system about 8 times Thursday morning. Added 2 gallons of straight anitifreeze and bought a 3rd before going on our camping trip. Checked level next day and it was low so added another 1/2 gallon or so again (total now of 2 1/2 gallons of antifreeze). Tested it tonight after engine cooled and now at the top end of protection. I am much happier with the look of the coolant. Can see green in the overflow tank where before it was dirty yellow. Thanks for the tips.

 

Good catch, you'd be surprised at how many people don't realize the antifreeze has to be cool for the test to be accurate. Glad you're all set.