# DIY Coolant Flush and Fill Audi TT 3.2l VR6



## TT4LEE (Mar 8, 2015)

*Audi TT with the 3.2 litre VR6 engine - Coolant Flush and Fill*










Here's my process:

This method only requires one hose clamp location disconnection (easily accessible) and drains about 6 litres (1.5 gallons) per flush, leaving only 2 litres in the block/heater core. The best information I could find says it holds 7-8 litres total.

This DIY takes a fair bit of time, depending on how long you spend heating the engine/coolant, and how comfortable you are draining hot/warm coolant (the cooler it is the safer). I spent about 2 hours.

Supplies
1 gallon (3.8l) of 100% coolant concentrate G13 is the current VAG coolant. (OEM isn't much more expensive than generic - I paid about $26). Two worm drive hose clamps (optional). 4 gallons of deionized water - best to avoid any impurities that risk messing up the coolant chemistry.

Method of raising the car (wheel ramps and chocks work well)

T25, T30, T45 Torx, flat screw driver.

Vice-grips.

Drain pan that holds about 2 gallons of fluid.

Paper towels

Setup

Raise the car - I find ramps ideal for this job. Use wheel chocks.

















Remove the belly pan under the engine (held on by a variety of torx screws). Mine had some oil splatter from a prior owner, which I cleaned up.

Be sure the engine (coolant) is cool to avoid getting burned by steam.

Drain

Locate the one-way valve that is at the bottom of the radiator and held in place by a ratcheting hold down that seems tailor made for the coolant drain job.


























Using vice-grips (or a proper hose clamp tool if you have one) squeeze the clamps on either side of the one-way valve and pull the hose off - at this point coolant will start to flow out fast so have a pan underneath to catch the coolant. Note the directional arrow on the one-way valve. Remove the other clamp and hose from the valve (each side drains about 3 litres).









Remove the reservoir cap to assist in a complete drain. You should get about 6 litres of coolant.

Refill/Flush/Drain
Reattach the hoses to the one-way valve - this time using the worm gear clamps to make the job easier. Watch the direction you reinstall the valve.

Fill the reservoir to the MAX level with deionized water.

Start the engine (make sure you are in neutral and have the parking brake on)

Turn heater temp knob all the way to hottest, then set fan to slowest speed (defeat the auto mode and AC). This will open the heater core and thermostat. Run the engine until the radiator fans cycle on/off and the interior vents blow hot air. Burp the system by squeezing hoses being careful to stay away from belts and fan blades - top up the reservoir as needed. Let the car cool before draining&#8230;.

Drain the system (1st flush)
Refill w/ deionized water and cycle vent mode
Drain the system (2nd flush) After this the coolant should be fairly dilute looking.

Use the empty deionized water jugs to store the used coolant and take to a proper facility for disposal.

Last Refill

Refill the system with 1 gallon (3.8 litres) of concentrated 100% coolant and as that runs into the system top up with deionized water. That should result in a mixture of about 60:40 - 50:50 coolant:water allowing for the remaining slightly dilute mix in the system after the last flush

Finish up:

Spray some diluted cleaner anywhere that coolant spilled to avoid damage to the car and to keep kids and pets safe.

Reinstall belly pan and lower car. Drive the car with a bottle of deionized water with you, and check that the coolant level stays in the right range in the overflow bottle. I had to add another 200-300 millilitres of additional water as the coolant fully filled the system. Check again in a day or so when the car is cold.


----------



## Undisputed_88 (Aug 5, 2011)

Nice write up!

Iv always heard of garages recommending coolant flushes and brake fluid flushes etc

What is the reasoning behind doing a coolant flush and how often should it be done?


----------



## TT-driver (Sep 14, 2010)

Modern VAG coolants should last 'for ever', well at least till a radiator starts leaking or the water pump wears out. Then it's best to repair and fill up with fresh coolant. Same with when the timing belt is due and the water pump gets replaced.

Having said that, I did check the bottom of the coolant reservoir once and did find some debris in there. But not a lot and it's even questionable if a flush would remove it. I used a bit of cloth on a stick to remove it.

Doing this flush may make sense every 8 years or so on a car with a timing chain. One word of warning though: some TTs didn't only get coolant from the factory, but also a little silicates cartridge in the coolant reservoir. I don't know if after a flush such a cartridge should be added again of if that causes overkill. Some parts need extra protection by silicates, but other parts such as a seal of the water pump can get damaged by silicates.

See here for a bit more info on that cartridge:

viewtopic.php?f=19&t=320149


----------



## TT4LEE (Mar 8, 2015)

I just bought the car and it's almost 8 years old, so I'm replacing fluids given I don't have the full vehicle history. I agree the coolant is considered lifetime, but I prefer to refresh it to ensure the chemistry is balanced (cheap insurance). I didn't find anything wrong with the 8-year old coolant, it came out quite clean. Haldex fluid is the only other fluid I'll change at 8 years and 80,000 km (after oil and coolant).


----------

