[tinkerman]

Recently, I've been considering getting a vacuum coolant refill kit for use with a compressor, but I started to wonder if it would be possible to pull vacuum "directly"(with a vacuum pump) as opposed to via a compressor + venturi effect (which requires a lot of air)? I searched online and found one account by a motorcyclist* that used a hand pumped oil extractor (Pela 6000 Spherical Oil Extractor) along with a typical vacuum coolant refill system to pull a vacuum on his bike, then refilled coolant with the vacuum.
(*Vacuum filling coolant system : refer to link in attached text file)

I'm wondering if anyone has done something like this (pulling a vacuum on the cooling system) using a vacuum pump(hand pumped or motorized) connected to a typical vacuum coolant refill kit** on a car? If so, I'd be grateful if you'd share your experience, especially with photos of your set up.
**Note: I'm not asking about experiences with using a vacuum refill kit with the conventional use of a compressor/venturi effect to pull a vacuum.

Cheers~

[DrSealer]

Have you tried it? I was thinking about this too

[tinkerman]

Not yet... I'm leaning towards trying with "direct" vacuum (via a buffer stage), instead of via compressor/venturi method.

I don't already have a large compressor at hand, just a "fridge" compressor and an empty R410A refrigerant tank. I can make either a DIY "silent compressor" or something like a "vacuum bagging" setup used for epoxy/carbon fiber processing.

I'm leaning towards the vacuum process because it seems to require less hardware than for a compressor [which requires care in filtering out oil (in oiled pumps) and moisture, a pressure switch, a safety valve etc.], and less of a concern in terms of safety*.
*Dry vacuum tank vs. wet rusty high pressure compressor tank. Also the R410A refrigerant tank has a safety tab that would "pass gas" preventing a big pop, before pressure reaches its rated max of like 400 PSI. Yes I know the tanks are not for reuse, but I've done my homework(mechanical ёиgїиёёяїяg perspective of pressurized tanks) and know the tank's specs, limits, weaknesses, safety features etc. and I certainly would not do ANY welding on it like so many "brave" chaps are doing on YouTube.

For a "direct" vacuum process, I would use the tank as a "buffer" between the vacuum pump(converted compressor) and the coolant system. This is because I don't want the ripple of negative pressure(from the vacuum pump) to be directly transferred to the coolant system. I would create a vacuum in the buffer tank, pause the vacuum pump, then smoothly remove air from the coolant system to the buffer tank. This may have to be done more than once(depending on the difference in tank volume vs the coolant system), so it may take more time than using a compressor/venturi, but it would use less power, be quieter, cost less, and no concern of a high pressure tank.

I am still getting рдят5 for a compressor, just for the fun of building a DIY "silent compressor".

I look forward to your experience if you go this route as well... Cheers~

[2013m5]

You should Google or check at Amazon such as “ coolant vacuum refill kit”.

[tinkerman]

I've been eye-ballin' a "coolant vacuum refill kit" that seems to be nearly identical to the Schwaben 003466SCH01 (e.g. ~$87, ECS Tunning) and OEM Tools 24444 (e.g. ~$105, Amazon), but for only $69(Ha! )on Amazon, and it even has metal valve handles instead of the green plastic ones that some have cursed & bitched at.
If I go the "direct" vacuum route, I'd set aside the venturi attachment and connect the vacuum refill gizmo via hose to a vacuum buffer tank, which would in turn be connected to the vacuum pump(converted fridge compressor).

[larshutten]

Just keep an eye on sucked out coolant so your vacuum pump doesn’t make a hydro lock. Even if the coolant system is fully empty it still sucks out some coolant. So you need to create something inside your “buffer” to separate the coolant. Most vacuum pumps hate any fluids.

[tinkerman]

Just keep an eye on sucked out coolant so your vacuum pump doesn’t make a hydro lock. Even if the coolant system is fully empty it still sucks out some coolant. So you need to create something inside your “buffer” to separate the coolant. Most vacuum pumps hate any fluids.

Yeah, (even after first flushing out most of the coolant through the lowest drainage sections) I was thinking of using something like those vacuum brake bleed kits' brake fluid collector containers between the coolant system and the buffer tank. I actually have something like it that I got with an oxygen concentrator (it's actually an O2 humidifier) with essentially the same structure but with a pressure relief valve which I'd seal up.

Any moisture/coolant would be separated from the air that would enter the tank & eventually the vacuum pump. I could also add a real moisture separator(intended for compressor systems) between the buffer tank and the vacuum pump.

Even with all added care mentioned above, it would still be cheaper going the vacuum pump route than a compressor/venturi route (if starting from scratch without a shop compressor already at hand).