Best way to drain/flush coolant

[somedude]

Hello,

Tiguan 5N, 2012, with a CCTA engine.

What is the best way to drain the coolant, to get most, if not all of it out.
Most “guides” suggest disconnecting the recirculation pump hoses, but does that drain the rad as well?
I do not have (access to) a pump to suck it all out, if that is what shops do.

Any suggestions will be greatly appreciated.

 

[Bruce]

Probably the best source of such information is VAG themselves. You can gain access to their factory repair information for a relatively low price. Owing to all being in pdf format, you can download all the information you want onto a local drive. Then you have it for all future needs.

Please see Official Factory Repair information in the Ross-Tech Wiki.

 

[Eric]

VW can be very curt in their repair information for what they consider mundane techniques. I think for thorough flushing they'd probably just recommend filling and draining several times. My preferred method for forcing coolant out is to go to various points of the system, have two (and just two) hoses disconnected; blow compressed air in one (blocking the hose with your hand and running the compressed air wand through your fingers) and hope coolant comes out the other hose. Then reverse. At some locations you'll get nothing, and at some locations you'll get a lot out. I don't have a 2.0T so I can't help with the most prolific locations. I'd suggest sticking to hoses that are/were already disconnected or at least don't need an o-ring replacement, unless you're prepared to do that.

 

[somedude]

Thanks Eric, great advice, I will probably start with the aux pump, since it has smaller hoses anyway, easier to connect to air.
It’s the rad that I find more difficult to drain.

 

[Crasher]

To do it properly, is hard, dirty, wet hard work. You need a pressure washer and an air compressor plus a flushing tool attachment.

 

[somedude]

Crasher, thanks, but how does the pressure washer fit the bill?
Is that to completely flush and rinse the system?

 

[Crasher]

The pressure washer is to help back flush the system to get any sediment out, the compressed air and flush gun are used to blast the system clean with distilled water before refilling with G12 Evo which we mix 40% to 60% distilled water. VW sell a 50/50 ready mix but the UK has a pretty mild temperate climate, so 50/50 isn't necessary.

 

[Zenerdiode]

…before refilling with G12 Evo which we mix 40% to 60% distilled water. VW sell a 50/50 ready mix but the UK has a pretty mild temperate climate, so 50/50 isn't necessary.

Ah, that explains something for me. I got some G12 from TPS a month ago and to my surprise it was indeed 50/50 premixed. I’m used to ‘stilling my own water (we have a water still at work for all the flooded batteries we maintain) for mixing with G12. I wasn’t asked whether I wanted concentrate or premix.

 

[somedude]

The pressure washer is to help back flush the system to get any sediment out, the compressed air and flush gun are used to blast the system clean with distilled water before refilling

Thank you. Makes a lot of sense, but I will not likely attempt it.
For two reasons, I might screw something up, and I don’t think I need an extreme flush, my expansion talk is nice and clean.

I would be happy to get most of the coolant out, which means I might try the compressor to push as much out as I can.

Thanks for replying.