Foggy and steamy inside cab!

[philo_beddoe]

....and it smells a little like anti freeze, and the rag i used to wipe windows tasts sweet.  (For the record i only dabbed my tounge).  Help, need to fix fast.  Thanks

My guess is heater core leak?

[Jason S]

Sounds like a leaky heater core to me.

[philo_beddoe]

How do i access. I have no a/c.

[philo_beddoe]

I found this, this guy knows a few things.

https://r.tapatalk.com/shareLink?url=http%3A%2F%2Fforum%2E73-87chevytrucks%2Ecom%2Fsmforum%2Findex%2Ephp%3Ftopic%3D1949%2Emsg8376%23msg8376&share_tid=1949&share_fid=15802&share_type=t&share_pid=8376

[Jason S]

It looks like you posted the VileZambonie procedure: http://forum.73-87chevytrucks.com/smforum/index.php?topic=1949.msg8379#msg8379

Here's another link:http://forum.73-87chevytrucks.com/smforum/index.php?topic=33480.msg284468#msg284468

The procedure is also in the service manual: http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.msg252586#msg252586

Off the top of my head (it's been a long time since I had to replace one), the hardest part seemed to be gaining access to the lowest heater box stud that goes through the firewall. It may be easier to drop the inner fender a bit.  Once the nuts are removed from the heater box studs, it all slides back under the dash.

Here's a photo of the engine side of the firewall.  You can see the approximate location of the heater box studs (you may have to scroll down a bit):http://forum.73-87chevytrucks.com/smforum/index.php?topic=21690.msg179454#msg179454

[Irish_Alley]

and the rag i used to wipe windows tasts sweet.  (For the record i only dabbed my tounge).

lol cant say dont do this. cause i tasted someones oil off their dipstick to "tell" them how many miles were left of the oil life

[philo_beddoe]

Yah, lol. Sometimes ya gotta do things the ugly way to know for sure.

[philo_beddoe]

So why does all that stuff have to come off the firewall, and not just the two hoses? Doesnt the core come through the cab? 1st timer.

[Jason S]

The under dash box is what is bolted to the firewall, as well as attached to the defrost ductwork.  The heater core itself is within box under the dash. 

You need to unbolt and remove the box from the firewall and open it up to gain access to the heater core.

It's also a good time to clean out any trash that has accumulated inside the box (e.g., pens, gum wrappers, dirt, etc.) 

[philo_beddoe]

Ok, makes sense. Can i by-pass the core while i work on it, and still drive  Obviously no heat.

[zieg85]

Ok, makes sense. Can i by-pass the core while i work on it, and still drive  Obviously no heat.

Yes you can by-pass it but don't wait till it gets too cold to do it.(talking from experience)

[philo_beddoe]

Ok, got it.

[philo_beddoe]

Fyi...i'll continue this heater core project post on the other post, "heater core removal". So as not to double up.