My First Performance Mod: Installing a First Gen MercRacing Heat Exchanger

[@AudiC7Owners]

An important update to this video: As was noticed by @vosh mods in the comments, I plumbed my heat exchanger backwards. In the video I route the hot side (in-flow) into the top of the heat exchanger, which is where the out-flow should be connected. The U-pipe that I didn't use should have been connected to the bottom of the heat exchanger to connect to the in-flow line, & then ran the outflow line from the top of the exchanger to connect with the line on the drivers side of the car. Don't forget to use Coupon Code "audic7owners" to save 5% on your MercRacing Order! Updated Video Link: bit.ly/3y5dpfn Really sorry for any confusion this caused people. I will say that there was no notable differences in IAT's on my car versus other cars with the same mods.

[@EricPoindexter]

Just wanted to share that I just installed the merc v2 cooler on my C7 A7 this weekend and was able to do so without removing the bumper or crash bar. Only needed to remove the upper and fwd lower splash guard and the only “specialty tool” needed was a 90 air drill with stubby bits. Had plenty of room to slide the cooler in from the top to mark up the drill holes and came in from the bottom with the drill to install the bracket bolts.

[@AudiC7Owners]

Cool! Glad you got it done

[@arthuryoshi3485]

Are You planning to make more videos? This videos are really helpful, I have a 2013 Audi A6 3.0T and this videos help me for maintenance.

[@AudiC7Owners]

Yep. We have a few in the works. I pay for everything out of pocket so I do things as I can afford it.

[@davidsibble7429]

Waited for this video!! Amazing help, insight and detailed! Many thanks from this new C7 owner!!

[@AudiC7Owners]

No problem! Glad it helps!

[@therevin7]

Great video, no non sense or drama. Super useful detail about the coolant refill.

[@danblackfield8928]

God fucking bless you, there are not many people who film the work on A6s. Thanks for the video, hope you'll post a lot more!

[@whamalek]

Thank you very much for the instructions

[@urgedkrisby]

You can use the channel locks to break the radiator hose loose after you've mcve the clamp open you channel locks all the way, grip tge hose and twist and itll break all that crud away.

[@toddn.3123]

What album of chipmunks are you rocking? ;) Good video!

[@AudiC7Owners]

😂😂 Thanks!

[@sed6]

1:00 Not T27 torx bits 😢 They are 12-point 10mm Triple Square bits, available at any auto parts store and hella easier to find than that wrong bit...Great video though 👍

[@AudiC7Owners]

Mine are Def t27. Someone may have changed them out at some point

[@ADVANslf]

At the 32:40 mark you grabbed a black hose and connected it to the bleeding tool. Can you explain what that hose was and the purpose of it?

[@AudiC7Owners]

So the tool uses an air compressor to remove air from your cooling system by creating a venturi effect. Basically the Connie sure runs through the valves in the tool and the valves use that forced air to create a suction effect. After you do that, you open the valve that connects to the house in the bucket with the fresh coolant. Since the coolant system has no air in it, it is pressurized. As soon as you open the valve going into the new coolant it is going to stick in through that tube. What you are seeing at 32:40 is me connecting my air hose to the tool again after it is filled most of the way up. I was just using the tool to top off the coolant system. I hope this makes sense.

[@andrewgibson835]

Where did u get your rs style grill? Thank u for your video. Going to do crank and supercharger pulley grill and heat exchanger at the same time. Thanks again. Awesome awesome video

[@AudiC7Owners]

Sorry for the late reply! Look up StoneCarbon2009 on eBay and check out his store 👍🏻

[@Nickitchet]

Thanks a lot man! About to do this on my 14’ C7 3.0T. What kind of compressor you r using with this refiller?

[@AudiC7Owners]

No problem. I'm just using a regular portable air compressor. I think it's a 6 gallon tank

[@Nickitchet]

Audi C7 Owners International cool, thanks again mate

[@denansulejmanovic]

Do you recommend changing the pump well? Just on stage 1 at the moment

[@AudiC7Owners]

For your regular stage 1/2/2dp tunes it shouldn't be needed. I wouldn't worry about upgrading the pump until I was getting into the realm of maxing out the capabilities of the engine with bolt on's. (ie TB upgrade, ported charger, fuel pump, etc)

[@issam24604mb1]

When are you doing the PCV , waterpump and thermostat DIY great videos

[@AudiC7Owners]

Thanks man! We had all of that stuff replaced not long ago because it broke, but we were unable to get a video done about it. But there is a really detailed video from an S4 you can find on KZbin. It's the same for the C7.

[@ionutstefan7060]

Hi . Were you based? I have a a6 with heather problem

[@lauztarizonaboy8205]

Same tool you used to put in the coolant is the one that take out the air out of the system?

[@AudiC7Owners]

Negative. This is only a fill tool

[@asaltyrifle]

I know this comment is over a year old but to help out anybody else wandering through the comments and bring a little more clarity to C7 Owner's reply, it is definitely a vacuum/fill tool that's used to pull vacuum and fill the coolant loop. I think he answered "negative" because the tool won't pull vacuum by itself, you'll need to connect an air compressor to it.

[@omarnaseem792]

Great video wish was here when i was shopping for heat exchange but only recommendation i would have will be to use Evan's Water High Performance Coolant i found that works a lot better than OEM but i also running stage 2+ with full bolt on's lol :) and for most ppl change the thermostat whilst you at it common issues along with plastic water pump on the audi b8 s4 they did revise the design to a metal one but not cover under audi warranty

[@AudiC7Owners]

You don't really get access to the thermostat or water pump when you are doing this install. But if you ever have to remove the supercharger, those should definitely replaced along with the pcv and cleaning your valves.

[@anthonymiranda6825]

Audi C7 Owners International you should do a video on all that 😊

[@AudiC7Owners]

If I ever have to replace them again I will!

[@nickmhc]

What made you pick this one over the one from Canadian Auto Parts or APR?

[@AudiC7Owners]

Mercracing is the standard for hx'ers in the 3.0t community. They have the best performance at the best price.

[@nickmhc]

@@AudiC7Owners noted! Hopefully will be a consideration soon

[@lauretiu]

hey man, what insert you used for that bleeder/Vaccum tool you got there?(i assume is the Schwaben from ECS from the looks or color of it) I can not figure out the dang insert. mine is either too big or too small( i know about the expanding spin cap with the rubber on it but it won't help if I use the closest one on the small size it won't tighten enough even fully expanded , if I use the next one is too tight and it will pop out before I even get to touch the expending cap) tnx for the videos. I assume you have apr stage 2+ that you had to replace the heat exchanger or?

[@scq50s21]

Did you figure this out? I'm running into the same issue currently. The 35mm is too small and the 40mm is too big

[@AudiC7Owners]

I used the only one I had with my kit (bought used). It didn't fit snug in the reservoir, but when I pulled vacuum it sealed the tool to the reservoir. You can buy a universal adapter for these (looks like a cone).

[@AudiC7Owners]

At this time I was stock. I just knew that coming was a huge issue with these cars so I wanted to do this first. I'm IE stage 2 single pulley now. I'm also about to do an update video with some new MercRacing products

[@lauretiu]

@@scq50s21 i used the 40 mm one. got it wet(if you don't it will not fit in there for the life of it) with some coolant or water i think and shove it in there as good as i could without tightening it or anything and started pulling a vacuum. it held for me. it looked like it was coming off at first but once i started pulling vacuum it stopped popping out

[@scq50s21]

@@lauretiu awesome, thanks both of you guys for your replies. I got mine going now. Running the car as we speak to get it up to temp

[@anthonymiranda6825]

How is it performing 1 year later ?

[@AudiC7Owners]

Fantastic! No issues at all.

[@AdHominem888]

How iat running after the heat exchanger upgrade mate?

[@AudiC7Owners]

I need to do logs once it gets hit again to give an accurate answer to this, but I can tell you that I live in a hot/humid area in the summer & it was a huge difference in how long it took the car to get heat soaked compared to the stock exchanger.

[@AdHominem888]

Nice to know! I’m looking over a merc or jhm HX... now merc has 2 sizes of HX.. thinking of going with the bigger one.. Thanks for the replay, this channel is lit! 👏🏼👏🏼👏🏼

[@AudiC7Owners]

Definitely go with Merc

[@dantehooks1603]

Nice! I have an c7 a6 and Audi wanted to charge me $857 to service!! :( any tips? My car keeps telling me to service

[@AudiC7Owners]

What did the dealership say the service was for? They should have given you a list of services done for that quote.

[@dantehooks1603]

@@AudiC7Owners im sorry i just checked the inspection its $597 for scheduled maintenance. $883 to replace rear brakes and rotors, i had to decline the service haha

[@AudiC7Owners]

Dante Hooks those are definitely dealership prices. What area do you live in? My best advice if you don't want to attempt to change them yourself would be to find a reputable vw/audi shop in your area to do the work. Should be a better price. And what scheduled maintenance is covered for 597$?

[@dantehooks1603]

@@AudiC7Owners Im in San Jose CA all they said was "Recommend Scheduled Maintenance (Found Service Due Light on) " i definately want to attempt it myself, i changed my front brakes but i heard the rear ones could only be replaced by the dealer, and im not trying to mess anything up haha, im not sure how to get rid of the service light

[@AudiC7Owners]

You need to have VCDS for the rears to retract the piston. If you don't have access to that then you need to take it to a trusted shop 👍🏻

[@thepunisher6231]

Can you show me pls where is 3rd hole for bleed of? Thank you very much

[@AudiC7Owners]

It's on the passenger side heater tube going into heater core. You need to pull out heater hose to expose the bleed hole. The plastic plenum cover need to be removed to see it. Check out this PDF and go to page 37. Hope this helps. bd8ba3c866c8cbc330ab-7b26c6f3e01bf511d4da3315c66902d6.r6.cf1.rackcdn.com/PDF_23370_Audi_3.0T_Magnetic_Supercharger_Drain_Plug_Installation.pdf

[@Six2Raptor]

I’m stage 2 apr on my 2012 3.0 a6 still on stock heat exchanger…should I get this one over the other options???

[@AudiC7Owners]

You should get a merc racing hx over any other brand for sure

[@miket.8528]

I thought this was a mod for stage 2+. I didn’t know stock cars would benefit from the bigger heat Exchanger. I might have to look into this.

[@AudiC7Owners]

Having a cooler running motor will benefit any engine stock or modified. My car is on stock tuning and I live in the humid southeast. I can tell a major difference in the cars performance compared to last summer with the stock exchanger. Also, Merc Racing has a sale going on for 4th of july right now and is selling the unit for 300$! That's a damn steal.

[@Thtblkbrit]

Audi C7 Owners International jus got mine installed today.. cant wait to pick it up!!!! Definitely helps with heatsoak and timing pull at the top of the rev range right?

[@AudiC7Owners]

@@Thtblkbrit Heatsoak is helped tremendously. As far as the timing pull, yes this will allow your car to be able to pull better at the top of your rev range, and is almost required once you go past a stage 1 tune if you want to keep your power up at the end of your rev range.

[@miket.8528]

That sale is what lead me to your videos. I’ve been looking all day to see if it’s worth it and all signs say yes. I just need a shop to give me the okay.

[@AudiC7Owners]

Why do you need the ok from a shop?

[@isaiahallen1346]

great video! want to do this to mine..

[@AudiC7Owners]

Thank you! I highly recommend you do if you plan on upgrading the performance of your car

[@NinjaSniper7]

Did you disconnect the batter? I know it’s standard on domestic cars but I don’t know on these

[@AudiC7Owners]

Yep. I talk about it in the video i believe. But anytime you are working with electrical components you want to disconnect the battery.

[@luiszubillaga1463]

Hello Would recommend getting a 2016 C7.5 crec A6 versus an regular A6 3.0t 2015 and older.? Trying to decide if I should get a 2013 A6 or a A6 2016, the packages are similar, premium plus both.

[@AudiC7Owners]

The earlier engine has more room for development if you want to go crazy. But you can go stage 1 E85 with IE & see over 500 awhp. It would have to come down to options/miles/maintenance history for me. Another big part is which one you like the style of more. Facelift vs Pre-facelift.

[@luiszubillaga1463]

@@AudiC7Owners OK cool. Yeah crec with 500 hp on stage 1 and E85 sounds fun!!

[@fastslash25]

how come the old heat exchanger stays on the car? is it used for anything or could it be removed?

[@AudiC7Owners]

The old heat exchanger is completely removed. That's the piece that gets removed and drained. It looks like a small front mount intercooler. You might be seeing the AC condenser behind the exchanger.

[@fastslash25]

@@AudiC7Owners What's the silver one in the back at 25:35 ?

[@AudiC7Owners]

That's the radiator you are looking at. The oem heat exchanger was already removed in that segment. parts.audiusa.com/a/Audi_2013_A6-Prestige-Sedan-30L-V6-AT-Quattro/_53892_6227854/RADIATOR--COMPONENTS-2012-15-MAIN/1353100.html

[@fastslash25]

@@AudiC7Owners ohh alright thanks, I also just realized that the oem heat exchanger was clearly not there at 22:48 my bad

[@mikeortiz6584]

@@AudiC7Owners So black one is the condenser and behind is the radiator so the HC thats replaced thats strictly fot the SC right? Whats the smaller secondary HC on the side for? How come no replacement for that and I assume oem coolant pump works just fine no need to get fancy like what AWE puts out? Also where is the trans cooler located and I would assume its best to replaced it as well?

[@Jonse14]

How have you found the cooler so far? Would you recommend it? I don’t have access to the compression when filling the coolant . Is it easy to bleed manually? Thanks

[@AudiC7Owners]

I am loving it. We've had some really hot and humid days here in southeastern north Carolina recently and the car is performing extremely well. Without the fill tool, you can ask merc racing to install bleed screws on the cooler before shipping it to you. This would make it a lot easier to bleed compared to using the bleed screws behind the supercharger. It's recommended that you get the heat exchanger mounted with the lower hoses installes, and then prefill the exchanger from the top hose inlet before attaching the top hose. Then fill the system through your coolant reservoir and use the bleed screw on the exchanger. If you use the bleed screws behind the supercharger, be very careful not to break them.

[@AudiC7Owners]

But if you can rent or borrow a fill tool, I highly recommend going that route.

[@jaysondrool5180]

Audi C7 Owners International any chance you can do a video on divorcing the supercharger loop from the engine?

[@AudiC7Owners]

I might do one in the future, but as of right now I don't have a need for it. But I will add it to the list.

[@thepunisher6231]

Hello pls help. So do you Have hot tube from Passenger side to top hole of heatexchanger? Thank you

[@erickbren8702]

I own a C6, do you think it will fit?

[@AudiC7Owners]

Hmmm. Let me look at some videos on c6 front ends and get back to you

[@erickbren8702]

@@AudiC7Owners thanks man, I actually know that it does not fit.... bought it and I have to move the horns. But also I have to either move the crash bar about an inch forward or cut the crash bar (which is hollow). I really don't know what to do... and I was thinking about taking a hose coming from the output of the stock supercharger cooler and plug it in the input of the mercracing and then take the out of the merc to the pump. if you can help me figure it out I will greatly appreciate it.

[@AudiC7Owners]

Erick Bren yea everything I am finding is basically saying you are very limited by the amount of space in the C6. If you push out the crash bar that will impact getting your bumper to fit back onto your car. Cutting the crash bar will make it useless in the event of a front end collusion. Jeopardizing safety for this mod isn't worth it. I'm not sure I follow what you are talking about in the last part of your comment.

[@bwong3659]

How long does it take to receive from merc

[@AudiC7Owners]

I live close to where the products ship from so It only took a couple days for me. I haven't heard of anyone complaining about delivery time.

[@bwong3659]

@@AudiC7Owners I bought my middle of last month and still not received it, 🤔??

[@AudiC7Owners]

@@bwong3659 did they have them in stock? And where do you live? Have you reached out to them? The owner is very responsive

[@bwong3659]

@@AudiC7Owners it didnt say if it was in stock,live in las vegas,I replied back to the email then sent for the confirmation

[@AudiC7Owners]

@@bwong3659 Jose is very responsive. I'd reach out to him again and check on the order.

[@studentul69]

nice ink

[@whamalek]

Can I flush the coolant without using the vacum pump?

[@AudiC7Owners]

Yes. You would just have to bleed the system with the 4 bleed screws.

[@whamalek]

@@AudiC7Owners located at the heater core pipes right?

[@AudiC7Owners]

2 on the supercharger as well

[@aaronjames8547]

Hey, I know this is a stupid question but some kind of answer would help. I'm ordering the heat exchanger now but I've had my c7 a6 stage 1 jackal tuned for a month or two. I've never experienced heat soak and I never drive the car in sports mode or really get on it unless it's a cold day or cold outside at night. Do you think it's possible to keep the IATs low in these conditions? Or does the tune just raise the engine Temps regardless? I figure driving around normally and keeping the rpms down would help right? I just want to know if I should lock the car in the basment for now or if I can get away with common sense driving? Sorry for the book bro.

[@AudiC7Owners]

The more you tune the car (tune, pullies, etc) you are increasing the rpms of the supercharger which is increasing the heat of your IAT's. A heat exchanger is a must have to protect your engine. Even with cold temps outside you can still get over 80C during pulls without proper cooling control. Get a hx. You can also use my discount code (audic7owners) to save some money on your order

[@rickmink6749]

Seems like it would be much easier to drill the crash bar still on the car.

[@AudiC7Owners]

Rick Mink you have to apply some steady pressure for awhile as you drill, so having it off makes it a bit easier. On top of that you are going to want it off the car when you are fitting the exchanger to the brackets. But if you try it out I'd love to hear how it works out for you 👍🏻

[@rickmink6749]

Great video. Thanks for the response

[@AudiC7Owners]

Rick Mink no problem. If you see anything else that stands out let us know!

[@thepunisher6231]

29:30 i did it same and its wrong... i have hot water from passenger side and it have to be mounted to bottom hole

[@AudiC7Owners]

Make sure you watch our updated heat exchanger video we link to in the pinned comment.

[@thepunisher6231]

@@AudiC7Owners Ye Will thx.

[@voshmods3938]

Did you route hot/cold side correctly or am I confused. I thought Passenger side is hot side and should enter lower port and driver side is cold and should exit top port?

[@AudiC7Owners]

They are routed correctly. I believe the routing for a b8/b8.5 S4 is slightly different

[@voshmods3938]

I guess both methods work, maybe I'm old school, ha.

[@voshmods3938]

Amazing video by the way. Thank you for taking the time to make this! Very helpful.

[@voshmods3938]

FYI. Jose at Merc racing confirms the most efficient plumbing is -In flow at bottom -Out flow at top Not trying to take away from your video as it was very helpful. Just want people getting the most out of this upgrade

[@AudiC7Owners]

@@voshmods3938 No worries! That's how it is routed in my video. On the A6 the bottom line is the hot line, and the upper line (out flow) is the cold going back into the system. Thanks for the support!

[@cwalker7070]

You must be an electrician cause only we say Kleins lol

[@AudiC7Owners]

Haha. I'm not, but I picked it up from my dad who is pretty well versed in electrical things.

[@maxapollo1]

if you need another A6 for install vidieos let me know and ill drop my 2013 3T off ;)

[@AudiC7Owners]

Lol I'll let you know

[@catpaw2143]

I'm worried starting the car when filling the coolant reservoire might cause a problem with the sensors in the front bumper? Any advise on that

[@AudiC7Owners]

Put the bumper on before you fill if you are concerned.