bleeding cooling system
09-11-2010, 03:06 PM
#1
Drifting
Thread Starter
bleeding cooling system
can someone write a dumb-guide for me that's really step by step and not a copy of Clark's?
my car now has a 50/50 mix and we are trying to get the air out of it
tried it with the front jacked, undid the bleed screw, waited for a couple of minutes and no fluid came out - fans turned on
looking for solution(s)
just took the car for a 1 mnt run up and down this "private" street, and car feels great, I missed it so much ... though now that it's gutted, it's a little louder inside, and I can hear all the little rocks bounce off the bottom for the car, lol
thanks guys!
my car now has a 50/50 mix and we are trying to get the air out of it
tried it with the front jacked, undid the bleed screw, waited for a couple of minutes and no fluid came out - fans turned on
looking for solution(s)
just took the car for a 1 mnt run up and down this "private" street, and car feels great, I missed it so much ... though now that it's gutted, it's a little louder inside, and I can hear all the little rocks bounce off the bottom for the car, lol
thanks guys!
09-11-2010, 03:13 PM
#2
Drifting
Thread Starter
ah forgot:
all new hoses, new coolant tank, new cap, new fan switch, new waterpump and thermostat, new headgasket, basically new everything (except the radiator, BUT it looks good) - and everything works
I just can't get the low-down on bleeding the system
all new hoses, new coolant tank, new cap, new fan switch, new waterpump and thermostat, new headgasket, basically new everything (except the radiator, BUT it looks good) - and everything works
I just can't get the low-down on bleeding the system
09-11-2010, 03:33 PM
#3
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i don't see the part where you took the coolant reservoir cap off.
- backfill the radiator best you can
- drill a 1/8" hole in the thermostat so air can get past it, make sure the hole is facing the utmost portion up so air can escape (this did wonders for me)
- take the cap off for the coolant tank
- sloooowly take the bleeder cap off so the air comes out, when water/coolant comes out, put it back on.
- with coolant cap OFF on the coolant tank, turn the car on
- let car warm up for a minute or two. then unscrew the bleeder slowly, get a rag ready and let it spurt. it will just keep spurting. occasionally put the bleeder back on and let it cycle for 30 seconds or a minute.
- repeat this process till just water/coolant comes out
- wait for the thermostat to open. you can feel the lower rad hose, if it's cold it hasn't opened yet. when it is warm you will notice coolant may suddenly shoot out or go low. make sure the reservoir stays FULL while you do the bleeding. once the thermostat opens you'll have new bubbles from the radiator. keep bleeding and let her squirt.
- the thermostat will close, keep bleeding till just water comes out
go drink a beer or a koolaid, or a soda... whatever is applicable. let the car cooldown.
-Go back out, pop the bleeder, see if just water comes out or if air does. go ahead and turn the car back on (with the cap off the reservoir again) and continue this for one more thermostat cycle. if no more air comes out and only water comes out... you're done!
random example i made from google images.
- backfill the radiator best you can
- drill a 1/8" hole in the thermostat so air can get past it, make sure the hole is facing the utmost portion up so air can escape (this did wonders for me)
- take the cap off for the coolant tank
- sloooowly take the bleeder cap off so the air comes out, when water/coolant comes out, put it back on.
- with coolant cap OFF on the coolant tank, turn the car on
- let car warm up for a minute or two. then unscrew the bleeder slowly, get a rag ready and let it spurt. it will just keep spurting. occasionally put the bleeder back on and let it cycle for 30 seconds or a minute.
- repeat this process till just water/coolant comes out
- wait for the thermostat to open. you can feel the lower rad hose, if it's cold it hasn't opened yet. when it is warm you will notice coolant may suddenly shoot out or go low. make sure the reservoir stays FULL while you do the bleeding. once the thermostat opens you'll have new bubbles from the radiator. keep bleeding and let her squirt.
- the thermostat will close, keep bleeding till just water comes out
go drink a beer or a koolaid, or a soda... whatever is applicable. let the car cooldown.
-Go back out, pop the bleeder, see if just water comes out or if air does. go ahead and turn the car back on (with the cap off the reservoir again) and continue this for one more thermostat cycle. if no more air comes out and only water comes out... you're done!
random example i made from google images.
09-11-2010, 03:41 PM
#4
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I know on a typical car all that's needed is to run the car and watch the tempurature guage, when the tempurature guage peaks and then falls a tiny bit that means the thermostat has opened and popped that air bubble out of the engine block. Then you usually check the coolant level at the radiator cap (or in this case the cap on the resevoir) and repeat if necassary until there isn't any coolant loss at the cap. The only time this hasn't worked for me is on mid-engined cars with excessively long cooling tubes to reach the radiator at the front of the car. However I do not know if this will work on a 944 since it doesn't exactly have a radiator cap it has a resevoir cap and it might opperate slightly differently. It's worth a try though, as long as you keep an eye on the coolant tempurature while you do it nothing can really go wrong.
Edit: I'd go with the above suggestion instead of mine, that seems like more of a true bleed process for this car than my generic one.
Edit: I'd go with the above suggestion instead of mine, that seems like more of a true bleed process for this car than my generic one.
09-11-2010, 03:53 PM
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I know on a typical car all that's needed is to run the car and watch the tempurature guage, when the tempurature guage peaks and then falls a tiny bit that means the thermostat has opened and popped that air bubble out of the engine block. Then you usually check the coolant level at the radiator cap (or in this case the cap on the resevoir) and repeat if necassary until there isn't any coolant loss at the cap. The only time this hasn't worked for me is on mid-engined cars with excessively long cooling tubes to reach the radiator at the front of the car. However I do not know if this will work on a 944 since it doesn't exactly have a radiator cap it has a resevoir cap and it might opperate slightly differently. It's worth a try though, as long as you keep an eye on the coolant tempurature while you do it nothing can really go wrong.
Edit: I'd go with the above suggestion instead of mine, that seems like more of a true bleed process for this car than my generic one.
Edit: I'd go with the above suggestion instead of mine, that seems like more of a true bleed process for this car than my generic one.
on a 944 the coolant cap keeps pressure. if you remove the bleeder screw then the pressure at the cap keeps the coolant from coming out of the bleeder.
easiest way to explain it is that the bleeder screw is at a high point but is made so that when everything "evens out" coolant will want to spew out of it, but it can only do that if there is no restriction from the coolant cap.
here's a crappy ms paint explanation.
It works off of a basic principle of pressure. If pressure is greater on one end, the other end will try and level out to equalize that. So the coolant will flush from the reservoir and wand to escape out the bleeder. Since the bleeder is at a high point, the air will naturally want to escape that point.
On a normal car with a cap it's the highest point in the system, so you pop the cap and the air just keeps coming out till it no longer is in the system. on a 944 you take the cap off the reservoir and then remove the bleeder so the coolant acts as the high point or pressure to force it through the system, let the air find the high point in the system itself (the bleeder) and out.
Since our radiators are a closed setup (no cap) when the stat opens and completes a cycle, all the trapped air in there will find it's way back into the system all over again, so you get to repeat it a few times till it's all gone.
Has anyone here ever seen a motorcycle or car carb sync stick? They operate off of the principle of vacuum. Liquid is contained in 2 canisters. If one canister has unequal vacuum, there will be more fluid in one canister or the other. If it is equal, the liquid will be evenly contained because the pressure of the system is equal. It is a similar principle. Consider the cooling system one canister and the coolant reservoir the other. Since the reservoir is sealed (capped) the pressure CANNOT CHANGE, so the cooling system will just openly flow and do nothing, even with the bleeder off. There is nothing trying to escape the reservoir. Once the cap is removed and the bleeder is removed the liquid wants to find the "level spot" or even out and equalize. This in turn forces the air out, lets the coolant settle, etc etc.... hopefully that analogy helps.
09-11-2010, 03:56 PM
#6
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I'm not particularly familiar with the "Clarks" procedure, but I don't sweat the nose in the air thing and do the following:
Engine cold - fill system with open res and open bleed and full heat until fluid dribbles out bleed. On level ground, fluid will dribble from bleed when level stabilizes around the max line on res. Start engine, keep filling to point of bleed dribble and allow to idle until thermostat opens. Open(ing) thermostat is indicated by obvious coolant flow at the rear passenger side corner of the res where the small hose is located and this is when the level will change quickly. Increasing revs a bit will make flow more apparent . At that point, reduce to idle and keep adding coolant until you get a continuous dribble out the bleed. Close everything up before the fans come on, as that will draw air back into the system. Check levels when cool.
Engine cold - fill system with open res and open bleed and full heat until fluid dribbles out bleed. On level ground, fluid will dribble from bleed when level stabilizes around the max line on res. Start engine, keep filling to point of bleed dribble and allow to idle until thermostat opens. Open(ing) thermostat is indicated by obvious coolant flow at the rear passenger side corner of the res where the small hose is located and this is when the level will change quickly. Increasing revs a bit will make flow more apparent . At that point, reduce to idle and keep adding coolant until you get a continuous dribble out the bleed. Close everything up before the fans come on, as that will draw air back into the system. Check levels when cool.
09-11-2010, 03:59 PM
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I'm not particularly familiar with the "Clarks" procedure, but I don't sweat the nose in the air thing and do the following:
Engine cold - fill system with open res and open bleed and full heat until fluid dribbles out bleed. On level ground, fluid will dribble from bleed when level stabilizes around the max line on res. Start engine, keep filling to point of bleed dribble and allow to idle until thermostat opens. Open(ing) thermostat is indicated by obvious coolant flow at the rear passenger side corner of the res where the small hose is located and this is when the level will change quickly. Increasing revs a bit will make flow more apparent . At that point, reduce to idle and keep adding coolant until you get a continuous dribble out the bleed. Close everything up before the fans come on, as that will draw air back into the system. Check levels when cool.
Engine cold - fill system with open res and open bleed and full heat until fluid dribbles out bleed. On level ground, fluid will dribble from bleed when level stabilizes around the max line on res. Start engine, keep filling to point of bleed dribble and allow to idle until thermostat opens. Open(ing) thermostat is indicated by obvious coolant flow at the rear passenger side corner of the res where the small hose is located and this is when the level will change quickly. Increasing revs a bit will make flow more apparent . At that point, reduce to idle and keep adding coolant until you get a continuous dribble out the bleed. Close everything up before the fans come on, as that will draw air back into the system. Check levels when cool.
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09-11-2010, 04:01 PM
#8
Drifting
Thread Starter
AH, so as I let the car warm up, I should do it with the CAP OFF ?
that's what I found confusing the most ... am I doing this with the cap on or off, for starters
and drill a 1/8" hole in the THERMOSTAT? why? and do I HAVE to or it's an option?
thanks!
we checked the mix, and it's not great, going out for some more 89oct gas and get some more antifreeze
we already filled the system with antifreeze/mix, but I assume that everything still applies
that's what I found confusing the most ... am I doing this with the cap on or off, for starters
and drill a 1/8" hole in the THERMOSTAT? why? and do I HAVE to or it's an option?
thanks!
we checked the mix, and it's not great, going out for some more 89oct gas and get some more antifreeze
we already filled the system with antifreeze/mix, but I assume that everything still applies
09-11-2010, 04:02 PM
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normally that works since they are a self bleeding system.
on a 944 the coolant cap keeps pressure. if you remove the bleeder screw then the pressure at the cap keeps the coolant from coming out of the bleeder.
easiest way to explain it is that the bleeder screw is at a high point but is made so that when everything "evens out" coolant will want to spew out of it, but it can only do that if there is no restriction from the coolant cap.
here's a crappy ms paint explanation.
It works off of a basic principle of pressure. If pressure is greater on one end, the other end will try and level out to equalize that. So the coolant will flush from the reservoir and wand to escape out the bleeder. Since the bleeder is at a high point, the air will naturally want to escape that point.
On a normal car with a cap it's the highest point in the system, so you pop the cap and the air just keeps coming out till it no longer is in the system. on a 944 you take the cap off the reservoir and then remove the bleeder so the coolant acts as the high point or pressure to force it through the system, let the air find the high point in the system itself (the bleeder) and out.
Since our radiators are a closed setup (no cap) when the stat opens and completes a cycle, all the trapped air in there will find it's way back into the system all over again, so you get to repeat it a few times till it's all gone.
Has anyone here ever seen a motorcycle or car carb sync stick? They operate off of the principle of vacuum. Liquid is contained in 2 canisters. If one canister has unequal vacuum, there will be more fluid in one canister or the other. If it is equal, the liquid will be evenly contained because the pressure of the system is equal. It is a similar principle. Consider the cooling system one canister and the coolant reservoir the other. Since the reservoir is sealed (capped) the pressure CANNOT CHANGE, so the cooling system will just openly flow and do nothing, even with the bleeder off. There is nothing trying to escape the reservoir. Once the cap is removed and the bleeder is removed the liquid wants to find the "level spot" or even out and equalize. This in turn forces the air out, lets the coolant settle, etc etc.... hopefully that analogy helps.
on a 944 the coolant cap keeps pressure. if you remove the bleeder screw then the pressure at the cap keeps the coolant from coming out of the bleeder.
easiest way to explain it is that the bleeder screw is at a high point but is made so that when everything "evens out" coolant will want to spew out of it, but it can only do that if there is no restriction from the coolant cap.
here's a crappy ms paint explanation.
It works off of a basic principle of pressure. If pressure is greater on one end, the other end will try and level out to equalize that. So the coolant will flush from the reservoir and wand to escape out the bleeder. Since the bleeder is at a high point, the air will naturally want to escape that point.
On a normal car with a cap it's the highest point in the system, so you pop the cap and the air just keeps coming out till it no longer is in the system. on a 944 you take the cap off the reservoir and then remove the bleeder so the coolant acts as the high point or pressure to force it through the system, let the air find the high point in the system itself (the bleeder) and out.
Since our radiators are a closed setup (no cap) when the stat opens and completes a cycle, all the trapped air in there will find it's way back into the system all over again, so you get to repeat it a few times till it's all gone.
Has anyone here ever seen a motorcycle or car carb sync stick? They operate off of the principle of vacuum. Liquid is contained in 2 canisters. If one canister has unequal vacuum, there will be more fluid in one canister or the other. If it is equal, the liquid will be evenly contained because the pressure of the system is equal. It is a similar principle. Consider the cooling system one canister and the coolant reservoir the other. Since the reservoir is sealed (capped) the pressure CANNOT CHANGE, so the cooling system will just openly flow and do nothing, even with the bleeder off. There is nothing trying to escape the reservoir. Once the cap is removed and the bleeder is removed the liquid wants to find the "level spot" or even out and equalize. This in turn forces the air out, lets the coolant settle, etc etc.... hopefully that analogy helps.
09-11-2010, 04:05 PM
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The thermostat hole is an option. If everything is back together you may as well leave it be unless you want to start over. but for future reference a 1/8" hole in a stat will allow any air pockets holding behind it to find it's way out and into the system without affecting operation of the cooling system. some thermostats actually have bleeders in them for that purpose, ours don't.
you bleed the system with the cap OFF. As explained above, if it is left on, the pressure remained in the reservoir doesn't let the coolant in the reservoir flush the air out and even out the system.
I let my car warm up for a few minutes, pop the cap, then start slowly unscrewing the bleeder to start bleeding. it will not bleed with the cap on.
(don't worry, i did the same thing and left mine on the first time i did it, could not figure out for the life of me why the system wouldn't bleed)
Yeah some cars are pretty tricky haha
you bleed the system with the cap OFF. As explained above, if it is left on, the pressure remained in the reservoir doesn't let the coolant in the reservoir flush the air out and even out the system.
I let my car warm up for a few minutes, pop the cap, then start slowly unscrewing the bleeder to start bleeding. it will not bleed with the cap on.
(don't worry, i did the same thing and left mine on the first time i did it, could not figure out for the life of me why the system wouldn't bleed)
Yeah some cars are pretty tricky haha
09-11-2010, 04:15 PM
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