# Coolant Flush?



## vliou (Nov 22, 2009)

So I called a local reputable Audi mechanic today, and asked about a coolant flush (4 years for the car coming up in October 2010), and the price was fair, but he did warn me that on rare occasions this might be a bad thing because the flush might cause leakages (water pump etc), and it can be very expensive to replace if this is the case (which makes sense), but does this happen often? Am I better off leaving it in there?

I have 62000km


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## Krieger (May 5, 2009)

a flush causing leaks? id think not. if your system has holes or leaks, you'd probably know since its pressurized and any leaks would leak pretty well usually.

just flush it yourself, refill with water, run till warm, flush again, refill with g12, burp the system, top it off, ta-da!

im planning on doing this soon since i have to change out my thermostat and coolant temp sensor.


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## Meatstick62 (Apr 17, 2007)

What does "burp" the system exactly mean? I know it means to remove air from the system, but how? 

Also, the only place I see to dump the coolant from is the lower radiator hose. Is there a better spot?


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## Krieger (May 5, 2009)

yep, just pop the hose off and let it flow. 

and to burp is to remove air from the system. our system is pressurized, so really the only thing you need/ can do is to life the car from different directions to get air bubbles to start moving towards the reservoir, and to squeeze the coolant lines both while the engine is running and while it's not. 

you could also leave the cap off the reservoir to let the air escape, but its not needed. just drive a bit, pull over, check the amount in the res. and top off. continue for a few days.


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## DSGTIdemon (Apr 21, 2008)

im doing this tmrw.. i have spent all night looking for a diy mkv gti coolant flush and i got nothing to show for it. all i found was a mk4 gti diy.. 

1. When the engine has cooled down, remove the Vw coolant tank cap. 
2. Draining the Vw coolant from the 4cyl cooling system: 
Remove the lower radiator drain plug from the lower front of the radiator (Vw A4, Vw Passat). Remove the passenger side lower radiator hose. Remove the outer Vw coolant hose that connects to the oil cooler. To drain the heater core you'll need to remove the hose on the coolant flange or transfer pipe located on the back side of the engine. This hose goes from the cylinder head to the heater core. 

3. After the system is done draining, put the Vw coolant tank cap back on. Carefully work off and remove the smallest hose that is connected to the top of the Vw coolant tank. Be careful, the tank nipple likes to crack and break off. 
4. With a blow gun and compressed air on low, carefully insert the blow nozzle into the small hose. Wearing safety goggles, carefully force the air out so that any Vw coolant that's still trapped in the cooling system is released. 
5. Reinstall the Vw coolant drain plug. Reinstall the coolant tank hose(s). Fill the Vw cooling system with distilled water. Start the car and air bleed the cooling system as outlined in the factory Bentley manual. Run the car until the cooling fan comes on. 

6. Repeat steps 1 through 5 until the water comes out clean. 

7. Verify that you have the correct anti-phospate anti-amine G11 or G12 Vw coolant. If it's full concentrate, mix a 50/50 ratio per the Bentley manual. Fill your Vw cooling system with this 50/50 mixture. Note: Some factory Vw coolants sold by dealers are already premixed and do not require further delusion. 

8.Run the 4cyl engine and check for any Vw coolant leaks. 

9. Top off the coolant tank to the fill line. Do not overfill. 

10. Using a permanent marker, write 'G11 or G12 Coolant Only' on the Vw coolant tank. 
11. (optional) Be environmentally responsible and dispose of your old Vw coolant properly. 

Vw Coolant System Maintenance: 

1. Never top off the coolant tank with full concentrate G11 or G12 Vw coolant. Your Vw coolant should never exceed a coolant ratio of 80%. If it's over 80% an inefficient Vw cooling system will result, decreasing flow through the radiator along with poor heat transfer through the engine block. 

2.Always top off your Vw coolant tank using a 50/50 mixture. If you're in a pinch and don't have any, use a small amount of distilled water. Remember, adding large amounts of water will change the alkalinity of the Vw coolant and throw off the glycol to water ratio, making it less effective in cold temperatures. 
3. Never mix G11 blue coolant and G12 red coolant. It will turn into a brownish goo and plug up your Vw cooling system. 

also i read this :The cooling system flush stuff I used said to run the engine for about 10-20 mins to allow it to work its way through, also make sure you run the car's heater at full blast so that coolant is allowed to run through the heater core. 

Drain out all of that stuff (it's pretty soapy) and flush with hose water until it runs out clear from the drain port (with engine idling). 

Start filling it with your G12 mixture, but leave the drain port open until you see only bright pink G12 flowing out, then close it up and top off the system. 

is this right.. and if so how much liquid does our cooling system hold??


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## TheRocco (Jul 15, 2001)

When is the coolant flush recommended?


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## Krieger (May 5, 2009)

i wouldnt go shooting air through the system. just put distilled water in the reservoir as your draining it should get whatever isnt coming out. next, close the system up and fill it with water. run till warm, and the thermostat opens up. 

let it cool down. drain again. 

now, either put in water again, or just fill with your coolant and be done with it. 

having a bit of older coolant isnt going to hurt anything when 99% of it is new. :thumbup: 

Rocco, im not sure, but I am at 72,000 miles, and im doing it soon, then again in 20,000 when i change my belts out, and hopefully every 40k/ 3-4 years after that.


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