Vacuum coolant bleeder.

Ollie

RMS Regular
Messages
2,338
Location
Co. Down
Looking a cheap vacuum bleeder - hopefully only ever use it once. Has anyone has any luck with these cheaper ones? One expands to seal in the filler cap and the other looks like a rubber cone to create a seal. Is one better than the other? Audi.

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Ollie

RMS Regular
OP
Ollie
Messages
2,338
Location
Co. Down
Never heard of a vacuum bleeder for coolant, whats the issue or why do you need it?

Its in the workshop manual for the newer audis. You stick a vacuum on the coolant bottle then introduce coolant into the system so it draws it deep into the coolant system? 🤷‍♂️

Typical thermostat issues. Slow to heat up and temp dropped when idling. Replaced thermostat. Much better but temperature sometimes drops one bar in traffic or idling. I topped up the coolant after I replaced the thermostat and it didn't do the usual bubbles and coolant level hasn't dropped again.
 

NI_Volvo_Nut

RMS Regular
Messages
4,846
Location
Ballynahinch
Drives
Volvo's!
New one on me dude, logic would dictate air should rise to the highest point so running with the cap off should expell any air. Ill stand to be corrected though!
 

mikey

RMS Regular
Messages
1,874
Drives
Celica
Is she petrol or diesel? In with us (VW) the vacuum fill process is the same with both but there is a test plan on the computer for the Diesel engines which bleeds all the circuits of the cooling system and keeps the sheath back off the electronic water pump for 500 (maybe 1000) miles to help with the bleeding as you drive.
Those symptoms describe a water pump with a stuck open sheath to a t as it is circulating coolant all the time leading to a slow warm up and temp drop at idle.
 

mikey

RMS Regular
Messages
1,874
Drives
Celica
Yeah its a diesel. C7 a6 2.0tdi. So it needs plugged in?
Yes. If it’s the latest gen EA288 engine there is the bleeding test plan on the computer. If there is no improvement like I say I would be looking at the waterpump with the shroud possibly stuck open (they 8/10 times stick closed and cause overheating but they do stick open and cause the cool running issues). There will be no faults stored for the waterpump as it doesn’t have diagnostic capability. Only way to check is remove.
Edit: Work colleague has said you can buy aftermarket pumps without the shroud which will cause bad heating issues. Pictures below show shroud stuck in open and closed positions.
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