Coolant drain/refill questions

[austin1346]

I'm going to be using a vacuum bleed/refill tool for the first time to change my coolant this weekend.

Will I still need to open the supercharger bleed screws and the heater core bleed hole as well? I think this vacuum tool is supposed to get all air out but not sure if it will be perfect. I have new billet bleeder screws just in case.

Also, will a small harbor freight 3gal 110psi 0.6cfm air compressor be powerful enough to create vacuum? 90-110 psi should be plenty but 0.6 cfm seems weak. The next step up to 2.8cfm is more than double the price. I could also rent one with 3.6cfm for $18.

Anything else I need to consider? Thanks.

[Fresh.S4]

ive never opened up the heater core bleeder when i vacuum fill

[S4lty1]

How much coolant did you get to swap in? I'm doing a thermostat and the kit only came with 1 gallon but was debating doing all new coolant

[austin1346]

How much coolant did you get to swap in? I'm doing a thermostat and the kit only came with 1 gallon but was debating doing all new coolant

I read that it takes ~3.2 gallons, not sure if that's factory fill or for drain/refill since there will be some that won't come out.

I bought 3 gallons and I have an extra container of concentrate too.

[Erikbecker]

I'm going to be using a vacuum bleed/refill tool for the first time to change my coolant this weekend.

Will I still need to open the supercharger bleed screws and the heater core bleed hole as well? I think this vacuum tool is supposed to get all air out but not sure if it will be perfect. I have new billet bleeder screws just in case.

Also, will a small harbor freight 3gal 110psi 0.6cfm air compressor be powerful enough to create vacuum? 90-110 psi should be plenty but 0.6 cfm seems weak. The next step up to 2.8cfm is more than double the price. I could also rent one with 3.6cfm for $18.

Anything else I need to consider? Thanks.

When it comes to the supercharger bleed screws and heater core bleed hole, it's better to open them, even if you're using a vacuum tool. The tool is pretty effective, but sometimes those high points can trap air, so opening them up ensures you get all the air out of the system.
As for the compressor – the Harbor Freight 3gal 110psi 0.6cfm compressor should be okay for this job, I think, but I’m not totally sure. Just make sure it can keep up with the demands of the vacuum tool because keeping a steady vacuum is crucial. If you can, keep an eye on the vacuum level during the process to catch any ups and downs.

A tight seal between the vacuum tool and the system is paramount. Additionally, consider the ambient temperature; colder temperatures can affect the efficiency of creating a vacuum.

[austin1346]

When it comes to the supercharger bleed screws and heater core bleed hole, it's better to open them, even if you're using a vacuum tool. The tool is pretty effective, but sometimes those high points can trap air, so opening them up ensures you get all the air out of the system.
As for the compressor – the Harbor Freight 3gal 110psi 0.6cfm compressor should be okay for this job, I think, but I’m not totally sure. Just make sure it can keep up with the demands of the vacuum tool because keeping a steady vacuum is crucial. If you can, keep an eye on the vacuum level during the process to catch any ups and downs.

A tight seal between the vacuum tool and the system is paramount. Additionally, consider the ambient temperature; colder temperatures can affect the efficiency of creating a vacuum.

I did end up doing this with a larger 6 gal 110psi 2.8scfm air compressor and it was just enough. The air tank ran out after about 25 seconds of holding vacuum so I just had to do a few cycles of building vacuum, shut valves off, wait for compressor to recharge, then reopen valves.
Aside from having to wait for it to recharge it worked perfectly.

Also, the vacuum tool actually did get all the air out of the supercharger. After refilling I let it warm up, gave it some revs, and then popped the screws and nothing but coolant came out, no bubbles/air.

I didn't bother with the heater core bleed hole as it doesn't seem like any coolant came out of that loop, I only drained about a little over 1 gallon. I wanted to flush the heater core but I didn't have the right attachments/hoses.

For anyone else wanting to do this job, I used the OEMtools 24444 vacuum bleeder, worked great except for the 35mm spacer is too small, and the 40mm spacer is too big. I used the 35mm and tightened it all the way and it still wanted to pop out, it was tight enough to hold vacuum though I just had a friend hold it in place.

[Nillious]

I have found that after the initial bleeding process and you have some drive time on it, if you park on a slight down hill and bleed the intercoolers with the engine OFF and HOT you will get more air. I say hot because you need pressure to push the air out. If you have a cooling system pressure tester you could use that as well to pressurize the system If the coolant is still it allows all the air to collect at the highest point. I got zero air out with car running but as I said, with it off the still coolant allows the small air bubbles in the system to collect at the highest points.

[Nelson G]

I used a Husky 1 Gal. Silent Air Compressor which has a 1/2 HP motor delivers 0.8 SCFM @ 90 psi. It pressurized the system and filled it without a problem. Once it was filled I turned the car on ran the heat on high with the fan off and I did not open any of the bleeder screws. After a few minutes, I shut the car off and unscrewed the cap for the coolant tank and you could hear the air escape. I turned the car on again and after a few minutes, I did the same thing. Then I took the car for a short drive came back and checked the coolant tank, no air was escaping and the system was full.