Vacuum coolant fill

[purplezr2]

Guessing most OEM's that suggest vacuum bleeding have found in testing air behind the waterpump impeller can take the seal out during the bleeding process if just running the engine is used to move coolant through the system

 

[2ndGearRubber]

Guessing most OEM's that suggest vacuum bleeding have found in testing air behind the waterpump impeller can take the seal out during the bleeding process if just running the engine is used to move coolant through the system

What's the theory behind seal damage from the water pump being exposed to air in the system?

I've had a rash of coolant leaks, which after repaired also have dripping water pumps, usually with coolant temps above 150F. Not sure if it's related to driving around low on coolant and topping off, or if it's a red herring.

 

[ChefRex]

I bought the Harbor Freight (Maddox) it works fine. The Airlift is supposedly one of the better ones out there.

ETA this one https://www.cpsproducts.com/product-details/550000/

This is the one I have, very happy with it.

 

[Shortbuscandid8]

Had to drain wife's '16 Outback to install a block heater. The manual doesn't mention vacuum filling and I'd never needed it on any of my old beaters. Drained almost 2 gallons but could only get 1/2 gallon back in. Almost overheated the engine using their procedure. I'd bought an OEMTools filler off Amazon for my son's Audi, but didn't wind up using it. It worked great on the Outback! I'll be using it from now on.

 

[Wamsutta]

My Buick has a bleeder screw on the thermostat housing. It allows air to escape as the cooling system is being filled. When coolant starts running out of the bleeder, that means the system is full and has no air. Close the bleeder and you're good to go.

 

[richfinn]

I have never used or NEEDED one !

I bought one around 25 years ago to solve a problem we had bleeding the coolant system on a car I had built from scratch (a kit car), after this we would use it on anything that was problematic to get all the air out prior to firing up the engine for the first time, they definitely have a place for oddball systems.

 

[dscheidt]

What's the theory behind seal damage from the water pump being exposed to air in the system?

I've had a rash of coolant leaks, which after repaired also have dripping water pumps, usually with coolant temps above 150F. Not sure if it's related to driving around low on coolant and topping off, or if it's a red herring.

the coolant is a lubricant and coolant to the water pump shaft. No coolant, quick seal failure. it's also possible there are pump designs that aren't self priming, and won't expel air from the housing.

 

[Hal]

Just picked up a Mighty Vac unit today at a consignment auction. $20. I have no immediate use for it, but it’s something I have wanted for a while.

 

[Beerhippie]

Things like front radiators on rear/mid engined cars also are perfect for vacuum filling.

My Vanagon is a royal PITA to refill without vacuum. It can be done, but it sure ain't easy.