Vacuum filling coolant, what pump could be used?

[Skyrocket21]

To pull a vacumm on a car coolant system using one of these refill systems,


The obvious choice is a compressor, is there a less expensive alternative?? 76cm mercury or 0.5 bar pressure, something like that, some people have used a hand pump, Pella one:



What about something like a HVAC pump? or similar? any ideas? Without damaging anything.

[GreenV8S]

Skyrocket21 said:

The obvious choice is a compressor

I don't agree that is an obvious choice. A good compressor doesn't necessarily make a good vacuum pump and vice versa.

I've got an ordinary vacuum hand pump that I've used occasionally. It's quite laborious to pull a vacuum on the whole cooling system. If I was using it repeatedly I'd get a motorised pump.

[donkmeister]

Out of interest what is the benefit of vacuum filling a cooling system Vs drain/refill/top up? Or do some vehicles need it by design (i.e high points above bleeding points)?

[Peanut Gallery]

As a previous user of HVAC vacuum pumps, I would say avoid these for this situation, they can pull a big vacuum, enough to collapse hoses, but they do this very slowly, so it would take a long time to pull the fluid into your system.

Yes, I know you could just turn off the pump when the system is full, but..

Have you thought about a double action hand pump?
https://www.amazon.co.uk/Intex-Double-Quick-Hand-6...

Each pump pulls a big volume of air, but not sure of the mm of mercury that could be pulled.

[GreenV8S]

donkmeister said:

Out of interest what is the benefit of vacuum filling a cooling system Vs drain/refill/top up?

Some cars don't bleed well during a fill from dry without extreme measures. If you have one of those, using a vacuum fill will reduce the amount of air that gets left in the system.

[Polly Grigora]

Peanut Gallery said:

As a previous user of HVAC vacuum pumps, I would say avoid these for this situation, they can pull a big vacuum, enough to collapse hoses, but they do this very slowly, so it would take a long time to pull the fluid into your system.

You would have to suck it and see

[TEKNOPUG]

What did you go for in the end OP?

I need to vacuum fill my Cayenne and I'm leaning towards the PELA hand pump as I'll have more general use for it rather than a compressor.