How to Bleed your 3.0T Coolant System

This is our DIY on doing a full manual bleed on an Audi 3.0T supercharged engine (C7 A6/A7, B8/B8.5 S4 & S5, & SQ5). There are a few different schools of thought on this, but from my research this is the most comprehensive way to insure you get all of the air out of your coolant system. This method doesn't use any specialty tools that you have to purchase.
I showed how to bleed from every available bleed port, but keep in mind you may not have to bleed the heater core depending on your coolant loss from whatever job you were doing. Having said that, if you do bleed the heater core, I highly suggest removing the strut brace to have easy access to the heater core bleed port.

[@DanTuc]

I just did my PCV. Well stil on it. I can’t believe how much a pain in the ass everything is with this car. After watching this I’m even more bewildered

[@kerrymohammed5722]

awesome video, gone are the days when we can do a simple coolant bleed without having to consider all the different points where an air lock can happen. looking forward to next vid

[@AudiC7Owners]

Thank you! And yes... Nothing about audi ownership is simple 😂

[@JuanHernandez-wf6yz]

Awesome video! Working on getting the same HX has the one you’ve installed and definitely going to use this video for when I start to manually bleed the system! Great work cam, thank you for all the research you do for the rest of the C7 community!! 🙏🏽

[@AudiC7Owners]

Thanks man! I'll have the diy video for the HX up soon

[@tannerbeavers5823]

awesome video! i hit a racoon in my S4 B8.5 and i had to change out the heat exchange. Got it all on and bled the exchanger but was still over heating. so, this helped trouble shoot the issue. oh FYI; to stop the dinging while the door is open just press the "up" button on the end of the windshield wiper lever

[@pklifter]

Loving this, was going to fit my larger hx this weekend. Thanks heaps for sharing!

[@AudiC7Owners]

Let me know how it goes for you!

[@davidsibble7429]

Bravo 🙌🏼 Excellent example of full bleed on the 3.0t ! Definitely looking for Merc Racing to manufacture more heat exchangers to get this not only for performance, but for the good of this incredible mill!

[@AudiC7Owners]

You won't be disappointed!

[@giani_c]

Great video thanks buddy. The water pump is on its way out on my 2010 b8 s5 so I'll need to manually bleed the system once I've done the waterpump, thermostat and belts 👍🏼

[@user-uu2ti9hg9h]

Hello, I am doing my pcv and this video is helpful because I have to bleed my system after I’m done with my pcv on my b8.5 s4 13’ I really appreciate this knowledge and information. Thank you sir.

[@kevinriordan7842]

Nice video and it helps all the newbies out there. For what it is worth I have bled coolant system in my 2012 A6 a few times. All related to replacing SC intercoolers, replacing coolant pump and thermostat, etc. I follow the bleed procedure from Audi manual. I use a vacuum fill tool. Here is the big one, I have the APR coolant performance heat exchanger installed as it is self bleeding. The self bleeding feature of this is worth the extra $400 vs. a Merc heat exchanger. Also, as you mentioned get those 034 bleeders installed on SC intercoolers.

[@AudiC7Owners]

We may or may not have an interesting update for the MercRacing hx coming up soon...

[@ayewhite333]

thanks for this bud. One note - when I did this on my Q5, I mistakenly didn’t let the engine get hot enough for any coolant flow to the heater core. When I backed the heater hose off nothing came out at all! Had me worried for a minute haha.

[@jrn4765]

Thank you for being so detailed in step by step instructions , I own a 2012 audii A7 3.0t and last week I noticed spots of what looks like oil in my coolant reservior!!! I don't have a blown head gasket but could it be the oil cooler ?? If it is the oil cooler where is it located !! Please help 🙏 😢

[@DirtRider999]

Awesome video!! I work at a Collison shop that and this video was invaluable for me at work

[@AudiC7Owners]

🤘🏻🤘🏻

[@davewilliams7565]

Good detailed info. I have the vacuum fill kit, but in this kit is a pressure pump tester. I've found this the best method for final bleed, and you can you can buy these cheap! Just fill, run the electric pumps (Best if you have done the pump mod' on the charger circuit, then pressurize the system via the header tank and go round opening the bleed points. Also, as you have done, I'd advise replacing the SC bleed screws, those stoopid plastic screws are practically one use only. M6 1.0 thread pitch bolt does the job, transferring the rubber seal from the plastic screws onto the new metal ones PS, to stop the bleeping when ignition is on and door open, press the reset button on the underneath of the wiper stalk, twice.

[@AudiC7Owners]

Thanks for the info on stopping the pump! That would have been great to know 😂

[@trickymonk]

Great video! I got my new Mercracing HX installed and bled no problem, but I encountered problems on the heater core. I was able to remove the clamp and break the hose free, but turning on the ignition and heat set to high (no fan) didn’t seem to do anything. I have a 2018 A6 Sport which only has premium features. I don’t have digital HVAC temp settings, just knobs. I have a separate knob for the fan. The heater hose was within a couple millimeters of being pulled off the aluminum tube and I only got dribbles, no air or steady flow. Any suggestions?

[@jeremydedeste5137]

Amazing video 🙏🏼

[@mastalee1776]

New to the channel. I don't have the same car but I have a b8.5 s5. Same engine. Plus I'm new to the audi world.

[@AudiC7Owners]

This video will still help you out if you decide to do the mod. Very slight differences. Welcome to the channel 🙌🏻

[@MotivationOverload.]

I changed my pcv 2.5years ago and i didnt do anything of this bcs i had no time ans no internet connection where i was and i let the car bleed itself….(yea i know im an idiot but surprising i had no issue) anyway now i have a coolant leak :)) from the front of the engine and it goes down on the left side and it drops down from the front left corner of the oil pan rly cant find the problem i wached your video with the 9 common leaks but everything its ok…. so i think i have to take the front of the car off… or do u have some advice? Anyway i rly appreciate what you're doing, good job!!❤❤

[@williamlebowski5034]

That's a sick shirt brother, thanks for the video, it helped me out quite a bit.

[@AudiC7Owners]

Thanks man!

[@mk_ultrarunner]

Wow! Super helpful, but looks like a headache. Especially having to remove that stabilizer bar. I have a Q5, so it's definitely going to be a bit more cumbersome to try an reach that back heater core bleeder. Audi doesn't make anything "easy" to work on do they?

[@diyundercover2987]

I love your video as an a6 c6 3.0T owner. Overall, the a6 c6's video is lacking a lot. In that reality, I refer to the video of the owner s4 or a6 c7 for everything. Even more so when it comes to cooling systems. You are the best. (Please understand that I live in a country where English speaking skills are poor.)

[@AudiC7Owners]

Your English is great! Thank you for the kind words 👍🏻

[@oli31]

Check out That African Audi DIYer, he has a C6 3.2

[@pklifter]

Subcribed. Thanks for showing everything, even the 'gotchas' !

[@AudiC7Owners]

Thank you 🙏🏻

[@andrewholzgrove7331]

Great video! Thank you

[@AudiC7Owners]

No problem 👍🏻

[@Slowednreverbedd]

Is there a downside to only pressuring the system without bleeding the core sc screws and hx, I have aftermarket hx but don’t have that bronze bleeder screw on top as this video

[@jpstone9105]

Nice video man! That 2000rpm info was new to me, so need to bleed my system again as soon as possible!!! 💪👍 Btw, have you planned to isolate your charger cooling from the motor cooling circle?

[@AudiC7Owners]

Yep! We are working with MercRacing on a project that will divorce the system

[@darkside2303xxx]

When bleeding the supercharger, do you need to rev the engine up if you have the signal wire unpinned on the supercharger coolant pump? Shouldn't it circulate that system at 100% all the time? Great video btw.

[@AudiC7Owners]

No you don't need to rev the engine. Even at idle without the 100% duty mod the coolant pump is moving coolant... It just takes longer.

[@matr4787]

@Audi C7 Owners International ------- Hi, I watching your video from France and thanks to you, I make my own maintenance for my Audi A6 c7 diesel 3.0 TdI. But I have a probleme with my heater core, actually inside my car I put de heater, but there is no heat coming inside or a little. I think my heater core need too be flush. For the moment there is no leak from the heater core so I try to remove the two hose, but it's very difficult. Do you know the method to remove the two hoses so I can flush with my garden hose the heater core ?

[@AudiC7Owners]

You shouldn't flush your heater core. There is likely something else going on. If doing the normal bleed procedure doesn't fix it, then you should take it to a shop to have the problem diagnosed. Do not flush anything with your garden hose.

[@lg6355]

Just a little help on the beeping while in the car with the door open. If you push the button on the end of your wiper stick it shuts that beeping off.

[@TheKbrizzle81]

Question.. Just something little, but at 17:05. Can you turn off the door chime on your car by pressing and holding the Reset button underneath the wiper stalk? My B8.5 S4 does that, and I'm just curious if the C body's did that as well. Great tutorial by the way. I've learn some cool tricks from watching your videos.

[@AudiC7Owners]

We can do it with the selector buttons on the steering wheel. Thanks man!

[@TheKbrizzle81]

Cool! I was just curious. Also wanted to thank you for mentioning Lifetime Audi! I would've never known about them, otherwise. I may visit that place soon, but it'll be a whole day even for me if/when I do. I'm in Greenville SC sooo.. yeah. But hey, I really don't know of any other Audi only yards that are closer.

[@AudiC7Owners]

They ship too, but that can get pricey depending on the size of your part. But they are an awesome company!

[@TheKbrizzle81]

@@AudiC7Owners Thanks again, that's good to know. I'll definitly do a road trip over there in the near future, just to see this place in person. Love to drive, only problem is finding the free time to do a day trip like this. The 'to-do' list never ends.

[@mr.miller9409]

Quick tip, you can shut off the beeping when the door is open by pressing the arrow buttons on the left side of the steering wheel!

[@AudiC7Owners]

Yep! Some others have mentioned that to me as well 👍🏻

[@brizax]

Or just press the button under the right stalk

[@danedonahoe7961]

how would I bleed the OEM heat exchanger system? is there a screw or a hose like the heater core hose?

[@AudiC7Owners]

Depends on what hx you have.

[@geraldchuks3275]

I have a 2013 A8 do you happen to know how to bleed the coolant. My check engine light and coolant light came on after I removed the coolant and replaced the radiator. Any idea helps thanks that awesome video tho.

[@AudiC7Owners]

I unfortunately don't have experience bleeding the 4.0t

[@tonman4000]

This video was very informative!! But I have a question. My rear bumper is off because I am replacing it, you mentioned to not turn ignition on? I was about to turn the ignition on this evening when I saw this video. Can you clarify if the ignition should not be turned on or did you mean not to turn the car completely on (starting motor)

[@AudiC7Owners]

You can turn the ignition on with the rear bumper removed

[@tonman4000]

even if all the sensors are unplugged in the rear? @@AudiC7Owners

[@Alonso_99]

Do you have a link to the vacuum bleeder kit? Thanks a lot 💯

[@AudiC7Owners]

I don't, but you could just search on Amazon for any decent bleeder & you could be good

[@mosinnagant76]

I am doing a PCV valve replacement and have 1 gallon of G12 EVO coolant. Is that enough or how much coolant should I expect to use for a completely drained fill and bleed?

[@AudiC7Owners]

You will need more than one gallon of 50/50 coolant, but less than two

[@Princeali_11]

Do I have to bleed all 3 if I’m only taking the supercharger off and putting it back on, I’m planning to do an oil filter housing replacement and need to take supercharger off but just wondering if I need to do all 3 as opposed to just bleeding the sc.

[@AudiC7Owners]

Depends on how much coolant you drain

[@amjadghanem9897]

Do you need to bleed the system if you replace the coolant tank/ reservoir?

[@AudiC7Owners]

No

[@BrovarianMotorWorks]

This was knowledgeable info but I'm on this Q7 with the same motor and can't find all of the bleed ports

[@AudiC7Owners]

What year q7?

[@cedricrodriguez9474]

How about the oem?

[@pacificrocknorthwest5612]

How much did it run you to get the the sensors at the bumper fixed?

[@AudiC7Owners]

I didn't end up having to fix anything. Got lucky.

[@YouTubeHandlesAreStupid]

@@AudiC7Owners Is it OK just to leave the bumper off or hanging and connect only the harness? Is there enough cable to do it?

[@AudiC7Owners]

Not if your car is on jack stands. You'd need something to put your bumper on to support it.

[@craighansen3031]

Hey you know if you press and hold the left scroll dial thing on the steering wheel it stops the beeping with your door open 😮🎉

[@daviddebuhr8995]

Nice video....$10 at autozone for some hose clamp pliers would have made this easier for you to get that clamp off without pulling the brace.

[@AudiC7Owners]

Trust me... I was thinking about that the whole time

[@kevinriordan7842]

At 17:13 when turning on heat full on, the door chime is beeping. Push either left/right arrow on the left side of steering wheel and it will silence the chime.

[@AudiC7Owners]

Thanks!

[@oli31]

Top tip!

[@YouTubeHandlesAreStupid]

You can VCDS this out as well. Best mod ever.

[@AudiC7Owners]

Yep. And obdeleven... I should probably do that lol

[@YouTubeHandlesAreStupid]

@@K24-SRT www.audizine.com/forum/showthread.php/403694-B8-B8-5-VCDS-amp-Hidden-Menu-The-Complete-List?p=14459373&viewfull=1#post14459373

[@JasonDostie]

Hit the button on the bottom of the wiper control and it silences the door alarm

[@pklifter]

17:04 Hit the button underneath the cruise control stalk :)

[@yahirpadilla7249]

So I just got this message on my dashboard saying “coolant system: fault turn off engine” any idea on what this can be or how it can be fixed?

[@AudiC7Owners]

There are so many things that could result in that error. Have you checked your coolant reservoir fluid level?

[@yahirpadilla7249]

@@AudiC7Owners i have and it’s a little low, but I also just got my engine replaced

[@AudiC7Owners]

I'd have it towed back to them if it was just replaced. Don't drive it until you know what's going on.

[@Leakybags5]

Do I need to bleed my heat X if it’s stock?

[@AudiC7Owners]

You only need to bleed if you have introduced air into the coolant loop

[@Snail2G]

Amazing video, however one issue I've run into is my heater core won't bleed. I've had it running like in the video for maybe 10 minutes and still nothing, however, I can hear coolant flowing all throughout the tubes, which I didn't hear before, so something is happening. Hopefully it bleeds soon 🤞🏻🤞🏻

[@dylanbryant3772]

I’m having this issue rn. What did you do to fix it?

[@Snail2G]

@@dylanbryant3772 I ended up trying that a few times and no coolant still. I did another pressure bleed while making sure no air got into the system to force some more coolant in, sealed it off, and called it a day. The car's been driving fine no over heating but once or twice my temp gauge has dropped a bit while driving so there is air in there somewhere.

[@dylanbryant3772]

@@Snail2G awesome thanks man. Just did a makeshift funnel to have coolant level higher than the heater core hose and it did the trick for me just now. Will have to probably take out some coolant in the end

[@Snail2G]

@@dylanbryant3772 oh yes that too!! I unbolted the reservoir and raised it above the heater core and I did get a bit of coolant to come out, but it was more of a "decent trickle" as opposed to a gushing flow of coolant lolll.

[@AudiC7Owners]

Did you make sure your heat was turned all the way up but fans off when you bled the heater core?

[@c7esaiah]

Hey man i need your help, I need to replace that entire hose you used to bleed from. I cant find it anywhere online though, any chance you know the name or part number?

[@AudiC7Owners]

Which hose?

[@c7esaiah]

The outlet heater hose

[@AudiC7Owners]

For the heater core behind the engine?

[@c7esaiah]

@@AudiC7Owners yes that one, underneath the strut bar👍🏽

[@AudiC7Owners]

You should be able to find it in one of these diagrams parts.audiusa.com/Audi_2013_A6-30L-V6-AT-Quattro-Prestige-Sedan/Cooling.html

[@kevinwonsetler3777]

My plastic bleed ports broke. They completely screw out, correct?

[@AudiC7Owners]

Yep. We have a video showing how to extract them

[@rsslljcks]

Does anyone know where I can find a engine layout with parts because I ha e a real bad gas leak on the driver side and it's dripping down on the serpentine belt but I can't find up top where it's coming from

[@AudiC7Owners]

Google "audi parts" & search for your car in the Audi parts website. You can find diagrams of your car that way

[@rsslljcks]

@@AudiC7Owners ok thanks

[@benjamensissom4653]

My 2013 A6 3.0T does'nt have a heat exchanger at all. I'm having issues with my dash screaming "Coolant System Failure, Turn off Engine." Is bleeding the system and ensuring theres no air even a possible fix? My only bleed locations are up at the windshield hoses and the supercharger. Would you think my issue may be the CTS instead? Please Help:(

[@AudiC7Owners]

You have to have a heat exchanger of some kind, even the OEM one. If the car is telling you to turn the engine off, then keep it off until you figure out what the issue is. You will only get that if you don't have enough coolant somewhere, or if the car senses that coolant isn't flowing properly. If you don't know your way around the engine very well then get it towed to someone who does. Do not drive it.

[@benjamensissom4653]

@@AudiC7Owners It definitely isn’t flowing properly. I’ve been diagnosing it for a few hours. It idles fine and stays cool. But the error messages stay. Engine coolant gauge on dash staying midway per usual. Only if I do more than idle does it increase. I don’t see any leaks so I don’t believe it’s any major hoses like I’ve seen people replace such as water pump, thermostat, coolant pipe, or vent pipe. It’s just not flowing right!

[@AudiC7Owners]

It actually sounds like your Thermostat has failed to me. But you should scan the car to see what it says. Water pump failure would result in lots of coolant leaking.

[@ian4665]

@@benjamensissom4653 I am currently experiencing the same exact issue, did you figure out what it was? My guess is thermostat

[@benjamensissom4653]

@@ian4665 It was the water pump, but I changed thermostat as well.

[@98f5]

I had something fly up and go through that tiny intercooler radiator. ended up going with merc also. way less heat soak, shoulda removed my bumper was a real pain int he ass.

[@AudiC7Owners]

You didn't remove the bumper to change heat exchangers?

[@mcld4214]

Swirl pot?

[@luanpham8962]

How can I activate the coolant pump using OBDEleven? Thanks!

[@luanpham8962]

Anything?

[@AudiC7Owners]

Sorry man. Been very busy. I haven't been able to find the function on obd11 to run the coolant pump yet. I'm still researching it.

[@luanpham8962]

@@AudiC7Owners Yeah, I can't seem to find anything online about it either.

[@Eman7335]

It’s not possible

[@wordup1818]

There is two output tests for coolant pump

[@panadol7930]

Is it the same in Q5 2018 ?

[@AudiC7Owners]

It should be the same for all 3.0t supercharged engines

[@jevafrass6181]

What is you don’t have a custom heat exchanger

[@AudiC7Owners]

Still do it the same way. But a pressure bleeder or vacuum bleed tool would be best

[@keepthinking2666]

Perfectly clear cooling looked perfectly orange to me. What the heck are you running in there?

[@AudiC7Owners]

Vw/audi coolant is a fluorescent orange/pink color

[@98f5]

how do i turn on the coolant circuit with odis or vcds?

[@AudiC7Owners]

I'm not sure. I have obd11

[@98f5]

@@AudiC7Owners if i used a vacuum fill tool should i still bother to bleed manually! Thanks for all your content btw lol nvm you answered at 2:30

[@AudiC7Owners]

Yep. Just to answer in the comments, you should still bleed manually after using a vac tool. 👍🏻

[@AudiC7Owners]

Maybe not for a stock car driven normally. But for those trying to get every bit of performance & has an aftermarket heat exchanger then you have to bleed manually after using a vacuum pump to insure every bit of air is removed from the system.

[@AudiC7Owners]

I understand that, but the aftermarket heat exchangers have a lot more areas for air to get trapped in. This is a VERY common issue in 3.0T engines that experience high IAT temperatures during 1/4 mile runs. Air gets trapped in the large heat exchangers after a vacuum bleed & has to be manually bled to remove. You can argue all you want about that, but it is well documented in the enthusiast community.

[@DjejeeMeejeje]

what if we don’t have a heat exchanger

[@AudiC7Owners]

You have an oem one which is very small and usually pushes all air out when you fill the system.

[@jeremydedeste5137]

Turn off the beeping by pressing on the reset button 😄

[@Madetolast88]

Coheed and Cambria? Did we just become best friends?

[@AudiC7Owners]

🤘🏻🤘🏻🤘🏻🤘🏻🤘🏻

[@travist9874]

Ive left my bumper off plenty of times when the car running, as long as u dont move the acc unit itself itll be fine.

[@AudiC7Owners]

Wish I could say the same for me this time... ACC needs to be realigned.

[@Krsonecf]

@@AudiC7Owners Did you end up having to go to Audi to get the ACC realigned?

[@AudiC7Owners]

I haven't done it yet, but I do need to get it realigned

[@Krsonecf]

@@AudiC7Owners I saw an article on the forums about doing it with OBDeleven. I’ve been thinking about try it. Would you like me to find it and send it your way to see what your thoughts are?

[@AudiC7Owners]

I've read it, but I still think it is way more complicated if a job than that thread leads on to believe

[@WillieWheels]

Super long … A lot of talking, and little work! 😂. Nice job 👍🏽 bro!!

[@Handlehandlebars]

The more I own my girls a6 prestige...the more I hate this car

[@AudiC7Owners]

Cool story bro

[@Handlehandlebars]

@AudiC7Owners it's actually not ...I work for a living and have kids and the money I have to dump into this thing thats been more unreliable than Any other car I've owned is anything but a cool story bro

[@AudiC7Owners]

@@Handlehandlebars sounds like the car wasn't taken care of. Hopefully some of my videos can help you save some money repairing it.