Can't pull a vacuum on my 2016 CX-5 coolant system

[Sljorgensen]

So I tried to use one of those vacuum coolant refill system on my new radiator and could not pull a complete vacuum and had to resort back to the old bubble funnel.

Looking at the radiator fill port design, the port going over to the overflow reservoir looks like it would be inside the vacuum envelope and it's not a sealed system.

Has anyone had success with a vacuum fill system on a Mazda radiator? What kind did you use? Mine is a rubber compression gasket style that pushes out against the sides of the fill port wall, but I doubt it seals off that hole.

I did try to seal off the hole by popping that hose off the reservoir cap and clamping it off. No joy.

Thanks,

-Scott in KC

 

[cz5gt]

bubble funnel works great even though Mazda official docs just ask to rev engine few times , supposedly self-bleeds.

Never tried vacuum before. Some cars require dealer diag tool but no the CX5 since its mechanical pump.

ps the expansion reservoir has open air vent..so prob thats why cant do vacuum.

 

[Jmaz]

I'll admit that I've never heard of a coolant vacuum fill system but to my cynical self it sounds like it could be more trouble than it's worth. Might be easier to fill the old fashioned way and check and add as needed the next few mornings after sitting overnight.

 

[Odrapnew]

I think vacuum filling works best with systems where the radiator cap is on the overflow reservoir.
I've seen it done a few times and its seems to work well.

I believe my 14 Explorer calls for vacuum filling (cap on reservoir), but I've just filled it the old fashion way and haven't had any issues.