Porsche 996 Heater Core

[Van B.]

So, this fall I finally got that smell through the heater vents. I’ve owned the car for 9yrs and never had a problem but I also didn’t know if it had ever been replaced before.
Turns out it was all original! Not a bad run for the OE part! Everything is now superseded to 997 parts, but they all fit mostly the same. Pipe angle is a little flatter coming out of the core, but with the thinner 997 hoses, it just barely clears the A/C line. My recommendation is to buy the new hoses both for figment and because they’re cheap enough that it doesn’t make sense to reuse the old ones.
Take your time and you can peel up most of the putty from the top seal. The rest of it comes off with some acetone on a rag.

In all, thank goodness Porsche didn’t put this under the dash! It’s an incredibly straight forward job and can be done in less than a day. I made a weekend out it though and dove into the “while I’m in there syndrome” lol…

[Van B.]

Forgot to take photos of the job, but I took one before final reassembly.

[PCA7GGR]

When I started smelling coolant thru the vents, I got a recommendation to add Subaru Coolant Conditioner to the coolant expansion tank. It reduced and ultimately eliminated the smell.

Worth a try before diving in head first on replacing parts.

[Van B.]

I think I followed what you were saying. But, no, if you smell coolant through the vents, the heater core is leaking. Thankfully mine was only weeping and had not progressed to the point of drips or leaking into the interior.
The sort of practice you are recommending is a slippery slope of deferred maintenance. If that line of reasoning is followed, you can turn a great car into a junk pile in just a few years.

Van

[PCA7GGR]

The Subaru Coolant Conditioner has the ability to plug small minor heater core leaks. That is why my mechanic recommended I use it.

"The sort of practice you are recommending is a slippery slope of deferred maintenance. If that line of reasoning is followed, you can turn a great car into a junk pile in just a few years." - kinda harsh.

[Van B.]

Perhaps. It wasn’t meant to be an insult so, for that I apologize. I disagree with quick fixes in general, but especially with plugging leaks in pressurized systems on engines. Fuel, oil, and coolant will kill your car if not properly maintained.

Van

[touringmandan]

The Subaru Cooling System Conditioner is actually Holt's Radweld. Remarkable stuff. Actually cross-links (like your blood) when exposed to air. Absolutely not a repair, but certainly has a function. Allows you to make the necessary repair when it suits your schedule.
Or temporarily extend the life of a vehicle that is beyond practical/economical repair.