2001 Audi TT MK1 225hp Heater core DIY Warnings....
 

I just want to preface this with, I’ve done over 20+ heater cores in A4s, A6s, B5s, B6s, B7s etc.

THIS was my FIRST Audi TT and it was my daughters, and I said, SURE, I’ll do it over Thanksgiving….I did, but there are differences and it took me alone 2 days due to it being problematic and NOT the same as A4s or A6s etc. REMEMBER, you OWN a TT, it is SMALL.

Follow all the DIY’s you find out there for these cars, but BEFORE you attempt to do a Audi TT heater core, here are a few things that ARE NOT MENTIONED or are different.

The DIYs are accurate down until you get to the point of either moving or removing the crash bar / crossmember….AND the HVAC system.

You WILL need a buddy.

Get a cheap windshield wiper puller, they are $6 and will save you lots of issues….

Disconnect both pos and neg of battery, believe me, it will save you some codes.

YOU WILL HAVE TO DISCHARGE YOUR A/C!!! and Disconnect.....

The cross member / crash bar CAN NOT BE MOVED or removed without taking the windshield out on a TT. There are two 13mm bolts on either side of said crash bar which can only be taken out upwards, but, believe it or not, windshield is in the way….really? Engineering at its best…..but it still can be done…..

BEFORE you even try to get the HVAC unit out, make sure you disconnect and remove the outside air / fresh air intake sensor AND FLAP underneath cabin air filter or it WILL BREAK! Yes, I broke ours.

Make sure you have a VAG COM!

make sure you MARK where the steering wheel was when you take it off, and put it back exactly as it was…if it is not, your steering leveling sensor will cause your ESP light to come on and will not be able to be reset until the steering wheel is recalibrated either via driving or VAG COM.

There will be a CENTER BRACKET (which holds the right side of the radio and center console, you will see it in my photos to the left of the passenger side airbag....which I did remove as well) on the crossmember that is in the way, and if you do NOT remove the windshield, it can not be taken out of the scenario, but still can be done.

REMOVE the center console surrounding the shifter and the e-brake etc…believe me, it will help you a lot.

Story:

Had a head gasket leak in my daughters TT.
Redid head gasket/heads etc on my daughters 2001 225 hp MK1. Just a side note, Audi will tell you to buy a new head for that model, they do NOT MAKE intake or exhaust valve guides for this car, they require you to buy a new head!

For the normal 1.8 180hp motor, valve guides ARE available….but, on a high note, BMW makes a valve guide that fits perfectly if you cut them down and know a good machine guy…..which I do!

So, compression is good, we bled and bled the heater core, backwashed, CLR etc…to no avail…so, winter is upon us, and so, being the dad I am, said, sure I’ll do your heater core, I’ve done many, no sweat…or so I thought…..

All went well following all the DIY and my experience over the years, Dash and HVAC unit unbolted in 4 hours…..until we got the HVAC unbolted from the firewall and figured out that the crossmember could NOT be moved or removed.

In other cars and you will read this, that unit just comes right out….in a TT, the HVAC has sort of a pressure system to hold the HVAC in place. After you remove all the 4 bolts that hold it from the motor side of the firewall, you can pull and pull and nothing will happen. (the 4 bolts are the two on top and below the AC lines going in-you WILL have to vent and disconnect AC lines). And the other two are in front and to the left of the steering wheel from the motor side. They are 10mm, not the 13mm.

After putting a little pressure on the HVAC unit with a pry bar, we got it to come out of the firewall, but then, that damn bracket was in the way…any puzzlers out there at this point will go, there is NO way this is coming out…..well, this is where you either give up, or you bend that middle center console bracket very carefully in the middle to 90 degrees and with a little finesse you can get it out…this is where you will need your buddy, to remove and reinstall it.

Once it was out, we looked at the heater core and you will see, no corrosion, looked good, we are like, you’ve got to be kidding me…..ran the inlet side under the sink, and wow, hardly any water came out the outlet side of the heater core…hmmmm

Anyhow, re-assembled, bled system and heat has never been better.

I cut the heater core in half to see what was up…I found ONLY TWO of the orifices were clogged on the bottom of the heater core…..causing no heat, this is because….Audi heater cores are designed to work with low pressure.

Any questions, ASK BEFORE YOU START.....shoot me an email and I will try to help as I have helped others…

Heater
 

Thanks for this info, just had my 2003 TT Quattro 225 out last night and could smell antifreeze when I turned on the heater.
I don't drive it in the winter so will maybe tackle this in the spring. Looks like a challenge!

Awesome Post. Thanks

Awesome writeup, these were the only pics I could find of this project being done on the TT that are still up! I just completed the job on my 05 and the heater works great! A couple of questions for someone who's done this job. How do/can you get the smell of coolant out of the HVAC box? And im curipus why you say the VAG-COM is required. What did you use for in this project, just resetting CELs etc?

An update in my 05 seems to be a semi-easily removable crossmember! there was on bracket behind the steering wheel which looked as f the windshield would have gotten in the way for the bolt being removed, but that bracket was then bolted onto the main crossmember with 4 torx head bolts. after I got all the bolts loose I was able to move it out of the way enough to wiggle the HVAC box out. I was relieved at that as the AllData manual was telling me to cut and drill on the crossmember, but I was not about to do any of that.

As for the fresh air flap, mine was closed when I went to get it out, so after a bit of unsuccessful light prying, I left it in palce. Nothing broke as far as I can tell yet, but I should probably take a look from above at some point.

Thanks for posting this article! If anyone needs a fewtips form someone who just went through it, shoot me a PM.

Thanks. As for the pictures...I'm surprised PHOTOBUCKET is still in business....many many sites have lost all the pictures due to them requiring you to pay to remote host pictures now....

As far as the COOLANT smell in your HVAC....probably should've tried to clean it out when it was out of the car....and even if you did, the plastic absorbs some of the coolant if it sits in there too long.....

I had to use the VAG because my son in law put the steering wheel back on one notch off....which in turn triggered the ESP to turn off and the cruise not to work...so I used the VAG to reset it all after I centered the steering wheel again....LOL

Hmm, both my esp and abs lights are on. I've suspected it's due to some unrelated new issue with my brakes though.. Haven't tried cruise control yet, but I never pulled the steering wheel. I just dropped the whole column so maybe mine doesn't need resetting, but I'll look into it! Any idea if a slight misalignment in the column would cause something like this?

On the HVAC box, I did clean it out, but now it smells like degreaser missed with coolant, which probably just embedded in the plastic after several years of soaking in... I'm like a quarter of the way hoping that the degreaser goes and destroys my flaps so I'll have to pull the box again and I can toss in a new/good smelling used one this time around..

Anyways, thanks again!
PS. Go Photobucket Go!!

You disconnected the ESP sensor when you took the dash out, I misspoke, it WILL come on regardless of wether you take the steering wheel off or not, that's why I said you needed a VAG.

If your ESP light comes on/fault is triggered, your ABS light will be on as well (abs won't work) and your cruise won't work...these are all related.....

If you drive it for awhile, it should manually reset, but mine never did without resetting it with the VAG....

There is a way to manually TRY and reset the ESP light...I've tried it a few times with no success, but others say it has worked....you can google how to do it.

It also could be as simple as the brake switch not being plugged back in etc...which causes it to come on...that's why a VAG is beneficial.....

Help Needed heater core and AC Removal
 

Removed dash, glovebox steering wheel etc. How does heater core box get attached / Removed. Found 1 nut under tab in insulation bolt on engine side. AC is already degassed and expansion valve removed. 2002 Audi TT roadster. 180HP FWD

how many nuts are located in the engine bay for the heater box?