Thread: Coolant flush issue

So I followed the instructions that scottydogs laid out on how to flush the coolant. After draining as much coolant as possible from the radiator drain, I removed the tstat, put the housing back on, then removed the top radiator hose from the radiator. I had the top radiator hose drain into a PVC pipe and then to a bucket. I kept flushing until the water was clear, and then let the water pump finish pushing out the water. I even turned the heater on full blast to drain the heater core.

I re-attached the radiator hose, put in the new tstat and gasket.

So then I'm going to fill the radiator and it only takes about 1/2 gallon of antifreeze before it starts overflowing. It goes down some and then I start adding water. Maybe 1/4 of a gallon and it is now full.

I run the engine to open the tstat, and still water remains in the funnel going up and dow but never fully draining into the radiator.

I was expecting to use 1 gallon of antifreeze and 1 gallon of water, then top it off with 50/50, but it didn't even come close.

Any ideas?

Remove the thermostat and fill the motor through there first, then re-install. Top off the radiator and do what you are doing again.

Likely there is a giant pocket of air somewhere in the motor.

what five said. sounds like trapped air.

Sometimes it takes a week or two of driving it to fully burp itself.

Well that was a no go. It was completely full underneath the tstat.

I just added some more 50/50 in the spill free funnel, let it run until tstat opened. The coolant in the funnel went up, and it went down, and it bubbled some and I still had coolant remaining in the funnel.

I bled the air out from the bleeder screw and then shut it down. I guess I'm calling it good for now. I'll check it over the next few days, unless someone has another idea?

And this was actually my sons 2007 GP Base that we were working on.

After re-reading this, if you never drained the radiator again or pulled the lower hose after doing the flush you will never get more than like half a gallon of coolant into the motor.

The radiator would still basically be full and same with the lower half of the motor, so not much is going to go on and not much can push out the top hose via the water pump. I always pull the lower rad hose or drain the radiator after doing the flush to get the most water out of there as possible, then start adding a full gallon of straight coolant then water to top it off.

That definitely makes sense. Maybe I'll redo it in the morning. So much for it just taking a few couple of hours. Thanks for the help.

Scottydoggs

"how to flush coolant:


remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.


get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.


then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.


put your t stat back in, with new gasket, the upper hose back on.






now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.


now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it."

Just confirming this is what you followed? It doesn't say to open the drain anywhere.

I left mine run long enough I got out of the car, checked the garden hose, then waited for it to run clear. It puked outta there a while with no issue. Note the engine sat overnight before flushing.

The heater core's easy to flush through the hoses by the firewall.

I followed those directions to a "T" and all was well in about an hour.

Well, I gave it another shot, and I was only able to get a full gallon of pure antifreeze in there this time. I'm assuming the remaining was water from the flush. Here were my exact steps. Please let me know if I missed something, because I'm at a loss at this point.

1. Drained as much as possible from the radiator petcock valve.
2. Closed the petcock valve.
3. Removed tstat and replaced the housing.
4. Removed top radiator hose from radiator. (Attached PVC pipe to drain in 5 gallon bucket)
5. Started the car.
6. Ran hose water into the radiator.
7. Shut the hose off.
8. Waited for the water to stop coming out of the top radiator hose.
9. Shut car off.
10. Drained everything that I could out of the petcock, and closed it.
11. Poured in 1 gallon of pure antifreeze, and then the radiator was full.
12. Started the car.
13. Waited for tstat to open to see if it would take some of the water that I had in the funnel. It took a little, but not much.
14. Closed the radiator and waited for the fans to kick on.
15. Opened the bleeder screw and watched it bubble until clear fluid came out and then closed the bleeder screw.
16. Let the car cool for a few hours.
17. Topped off radiator with water.
18. Made sure the overflow tank was at the correct level.

Done.

Check your concentration with one of those $3 testers. Hydrometer is the fancy name. Peak and Prestone come to mind. Small plastic thing, fits in the palm of your hand. Its got a small "turkey baster" bulb on top. Just suck up some coolant out of your rad and it will float a needle to show your freeze/boil points. If its too weak, drain some and add some full strength til you get what you need. Nothing wrong with filling your overflow tank above the line either, you can go a couple inches from the top, it'll get sucked in sooner or later....E

we got roughly a 3 gallon system, 1 gallon of coolant puts us at -20. the rad its self holds about a gallon.

I got one of those Peak testers yesterday, and I tested it and it came back just over -35F and 265F, so I'm calling it good. And the heat works now, which is what he was complaining about all winter. New tstat and the green coolant.

And maybe I'm not waiting long enough for the water pump to finish? I waited until nothing came out of the top radiator hose for about a minute. I was also on ramps (about 4.5 inches off the ground), so I don't know if that makes a difference or not?