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View Full Version : Pre-facelift heater core WTF deal



rollerton
11-17-2018, 03:40 PM
Ok, I swore I'd never post a 'heater core' thread. It is what it is, and I haven't had to deal with one of these for about a decade since I owned a B5 Passat. So, sorry for this.

Anyways; I picked up a really decent 98' a couple weeks ago ($200! / original owner). Runs amazing. Just needs some seals, tensioner pads, and whatever. But of course no heat. Like NONE.
So, #1. Flushed heater core of course. I filled it w/ CLR, flushed it out, bled it thoroughly. I have HOT coolant both in and out. Water flows very freely with the hose hooked up for flushing. Still no heat. No errors from HVAC crazy diagnostic menu and none via VCDS.
W/ VCDS I can cycle output tests and watch every flap move properly. Yet I still have no heat at all. I have the console, glove box and knee panels off so I can see/ reach just about everything I need to. But zero heat.
So, what do you at this point? Just go for the heater core? That's a shit ton of work to swap out a heater core that seems to flow totally fine. But the blend door seems to move totally freely. By the time I get to some point where I can actually put eyes on that flap and fiddle with it I'll be nearly at the heater core anyway.
So..WTF...just do it or am missing something? Haven't worked on a B5 in a decade....but I'm guessing there's no secret.

https://i.imgur.com/j4kiRjw.jpg

Ryanic
11-18-2018, 08:54 AM
This could be your problem haha
https://preview.ibb.co/nvumc0/Snapchat-1692006372.jpg (https://ibb.co/kV1A4f)

Just got done with my heater core last night.
I had great flow through the heater core and both hoses were hot.

Trust me I exhausted every option there was before I decided to go for it. Flushing did nothing since the barrier was broken for me.

I had minimal heat and it goes worse/disappeared anytime it was under like 20 degrees Fahrenheit. I dont think my core was very clogged but the broken barrier was the issue. The coolant would take the path of least resistance obviously so most of it just went in one hose and out the other instead of going down into the core

rollerton
11-18-2018, 10:29 AM
yeah...that's probably what it is. It's just disintegrating inside I'm sure. About 2" of the inlet/outlet stems on the core are jagged and dissolving..I'm sure it's crap.

Ryanic
11-18-2018, 10:44 AM
Most likely. Now to decide if you want to tackle the heater core. It's a bear but i'm so happy I finished it and finally have hot heat again. I couldn't handle another Midwest winter without heat.

rollerton
11-18-2018, 12:12 PM
Most likely. Now to decide if you want to tackle the heater core. It's a bear but i'm so happy I finished it and finally have hot heat again. I couldn't handle another Midwest winter without heat.

Yeah...I kind of knew this would be the outcome. guess I'll go have the A/C evac'd tomorrow.

https://i.imgur.com/GoYolyR.jpg

Ryanic
11-18-2018, 12:51 PM
Decent start. Make sure you have the right tool for the steering wheel nut under the airbag (My 98 was a 12 point, don't remember what size though). Otherwise everything else is mainly 8s and 10s. Couple various Torq and Allen sizes too. Good luck.

Also make sure you clean the outside of the new heater core with something, soap and water probably. I didn't take the advice of that from another thread and now my car is putting off a terrible smell as the oil that was on it is burning off... Its nauseating. Hopefully it burns off soon.