Winter is Coming, and heat sucks

[Nemesis2747]

So, I'm tired of flushing my heater core. I've done it twice. Gets better, still not good enough for freezing temps and still no heat at idle. I bled my car from the front bleed screw, from the heater core outlet, burped the system, I've done it facing uphill, done it facing downhill. Even on its side where Expansion tank is the highest point. I've done 3 full coolant flushes in the past year and a half. I even replaced the coolant tank from grey to clear so i can see coolant level easy. Getting New Genuine Audi core and this one is getting recycled. Anyone have any tips on replacing this thing.? 03 2.7T.

[G0to60]

How's your water pump? A weak or dying water pump can also have an affect on heat in the cabin.

Aside from that and your multiple flushes I would say your heater core is clogged beyond cleaning and needs replacing.

[brokenwrench]

What strength coolant do you use? On most cars I've seen, full/too high strength will prevent the engine from reaching full operating temp in cold climates.

[noob5]

Also to rule out your thermostat, your temp gauge should be at dead-center when at full operating temp. If it fluctuates, your thermostat may be bad.

If in fact it is your heater core, it is much easier to replace on the C5 than it is on the B4, B5, C4. Done it twice on my A4 and once on my 90Q...what a pain in the ass in those platforms.
In the C5 dash removal is not necessary, and you can access it through the driver side foot well and should be a relatively quick job.

https://www.youtube.com/watch?v=WTODVb8SRVA

https://www.youtube.com/watch?v=JmBk7GZufUI

[Nemesis2747]

Footwell time!! I keep a 50/50 of G13. Temp gauge rises to the center and stays there. Water pump and timing belt are almost due. Im @ 160,000. My oil temp climbs almost to half way when car is warm.





Im gona pull it out and try to flush it nice and hard before i spend $250 on a new core. Last ditch.

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[n8henn]

They have new cores at Europa for like $100 bucks.

[4rings2turbos]

Sweet, always thought this was a dash out thing based on what everyone had always said. Definitely gonna do it now since I've also never been able to get full heat back.

[PaperToast]

i would check to make sure that all the actuators/motors that control the various flaps are working before pulling the core

[noob5]

Sweet, always thought this was a dash out thing based on what everyone had always said.

Yes, this is a common misconception and was a reason I contemplated trading in the C5 if the heater core ever went bad, as I had no intentions of replacing another heater core in my lifetime. But learning about how easy the job is in these cars, was a major factor in my decision to keep the allroad. lol

[4rings2turbos]

Seriously, I've heard that so many places. I was waiting until my dash was out for an Alcantara wrap but I'm not waiting anymore.

[Nemesis2747]

My heater core is currently in my sink with its 3rd fill of straight clr. The little brown flakes of crap just dont stop coming out. I might end up walking to the store to buy 2 more bottles. Even using my sinks water pressure only a little bit of crap at a time come out. But hey, ITS COMING OUT. Taking out this heater core was probably one of the easiest things I've done to the car lmao! Hardest part was trying to get upside down in the drivers seat to get a good view of everything.

[Nemesis2747]

Took it out just fine. But im about to removing my front seat to put it back on.... I cant get those 2 stupid little clamps back on correctly. I need 4 hands. 2 to push together the heatercore and pipe and 2 more to line up and screw down that clamp. Those o rings push them apart :( At the same time i can barely fit 2 hands in there.

[Nemesis2747]

It is done. And the heat at idle right now is hotter than it was while driving on the highway before. Im going to tell u guys now that just flushing wont work. I flushed and filled and clr soaked many times. I thought it would be a good idea to fill it half way with water and shake it HARD. The water came out BROWN with huge chunks of... sediment? From the output side (top). Like a hard pastey clump of mud. And i refilled and shook it many many times until that water came out clear.

Word of advice if anyone tries this. The heater core metal is very soft. Its easy to bend the flanges. And if you do, those high pressure clamps will not fit and LEAK. If you dont put on those clamps perfect then it can further damage the flanges.

All in all im happy i didnt spend a cent to get heat back into my 2.7T for the first time in 2 years. I paid in blood, no sweat (40 degrees), and many curse words.

[Nemesis2747]

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[Audibot]

Disgusting... I am getting a flush tomorrow... hoping mine doesn't need to be changed like that...

[G0to60]

Yeah, that pretty much looks like what came out of mine but I just used hose water and pressure so it wasn't too badly caked in there.

[Nemesis2747]

10 days later and my vents are like blow torches. I love how even after maybe 30 seconds after starting the car in 40 degree weather, the air starts to blow warm. It gets nice and toasty before my coolant temp needle even moves. And if its raining, the heat WILL dry my shoes and pedals. After going the last year with luke warm heat ON THE HIGHWAY and no defogging, this makes me very excited! When it snowed i would have to have a micro fiber cloth handy so i could see out the windshield. And i haven't lost any coolant, no leaks! So happy.

And btw. Why does our heater cores fill itself up with this gunk? Did someone mix coolants once upon a time? Did they skip the 50K change interval? Mixing? Tap water? I got my car at 135K with a timing belt done at 90K at the dealer. The coolant was orange/rust.