woodvette03

trying to change the antifreeze in my '03. opened the drain plug in the radiator. only got about a quart of fluid out of it. the surge tank drained out too. this is suppose to be a 12.6 qt system. i don't think i was low on antifreeze. is there something else i need to do to drain the rest out?
thanks.

woodvette03

ok, i pulled off the lower hose and got a little more out. still only about 2 qts or so. i was able able to add 4 qts so far. i left the cap off the surge tank so the air would bleed out of the system but it keeps overflowing and the temp got very high. drove a block up the street and it got to the warning range and dash message said coolant temp high. is there another way to bleed the air out? what else am i doing wrong? never had this much trouble changing antifreeze in other cars.
thanks again.

ZeeOSix

Hint: I blew air into the reservoir tank filler cap hole with my mouth to help drain coolant from the system ... got a total of ~8.5 qts out of the system doing this.

Total system capacity is 12.6 quarts, so doing the back-blow trick got ~70% of the old coolant out.

guido7834

Why not use an air compressor to do this?

ZeeOSix

You could try it (and let us all know), but I didn't because I didn't want to risk over pressurizing the system. Plus, there wasn't a good way to seal the air hose on the reservoir tank. Guess you could remove the small hose from the tank and pressurize through the hose nipple (and plug the hose). The mouth pressure worked fine for me, so I didn't bother trying to rig something else up.

BigGun

Send pics!

ZeeOSix

This is how you prepare for the procedure ...

woodvette03

ok, i was only able to get not much more than 2 qts or so out even after removing the lower hose. however i was able to add 4 qts of new antifreeze. i guess i was low then but never had any overheating issues. i ran the engine to try and bleed the air out then turning it off. i saw air bubbles going into the surge tank. i thought the air was coming out. did this a few times. driving to work this morn, i was overheating after driving 10 minutes or so. temp got to 260. i pulled over several times to let it cool. saw air bubbles going into the surge tank again. i thought there was more air in the system. lucky i had a gallon of antifreeze with me. i finally decided i try adding more fluid. i was able to add another gallon. so totally i added about 8 qts but only drained out 2. i am assuming i was low for a good while. the thing that baffles me is that why i never had issues with overheating before if the system was so low? after i added that gallon, the temp went to normal finally. any thoughts? i am not familiar with this type of system. i am use to the older kind like in my C3.
thanks and sorry this is so long.

Chicago1

Use this method bleed the air from the heads..

http://forums.corvetteforum.com/c5-t...erheating.html

jim993

The air bleed manifold and associated piping, which is supposed to bleed air off of the heads is fairly small. A 1/4" inside diameter coolant hose fits the pipe outlet fairly snugly. The outlet from the air bleed manifold is then routed to the throtttle body, then to the right side top of the radiator.

My theory is that this plumbing system is somewhat subject to plugging because of its small size and in cases where the coolant is not changed fairly regularly.

The procedure referenced by Chicago 1, regular coolant changes, to the extent it can be changed and perhaps bypassing thr throttle body may help aid in getting the air out of the heads. As air does come out of the heads over time, you may find it necessary to add coolant to the surge tank a day or two after changing coolant.

In my case, I assembled a "tee" with valves into the air bleed hose just prior to the radiator connection, allowing me to vent the heads to atmospheric with the cooling system under presure. This also works to vent air off the heads after changing coolant. After bleeding, I remove the "tee" assembly to be ready for the next coolant change.

RedZMonte

I used Prestone Dex-Cool (GM Approved) 50/50 (2 Gal)
I drained mine at the radiator and via T-stat housing removal, replaced WP (was leaking) and T-stat (new OEM). I was able to fit almost 2 gallons of fluid in my car.. Most of it came out when i removed the T-stat from the block. I did fill the engine via upper hose until full then filled radiator and overflow.. did top off over flow a couple times but not much.. stayed steady no over heating.. The Radiator doesnt hold a ton of fluid and when the T-stat is closed the lower hose is removed the t-stat is still closed so you wont get much out without the t-stat out. When i did mine i also did the belts and new hoses (had them off anyhow)

* Drain Radiator Via Petcock
* Drain block via removing T-stat (replace T-stat)
* Fill block via upper hose
* Fill Radiator via Upper Hose
* Fill Overflow to HOT line (Top Off levels when hot)

guido7834

I didn't do it myself. I paid some one to change my coolant. Cheap enough and no mess.

RedC5

My normal procedure is to drill pump out the overflow every year get some fresh coolant into the system....this avoids any air complications. Gets a couple quarts out.