What do (did) these lines do? Y’all are super helpful. I don’t know much about his stuff.

 

After the thermostat opens, the temp gauge goes to the middle position and the heater blows HOT. I still don’t have good air flow at the defrost vents. When I switch it to defrost, the air stops coming through the regular vents. You can tell (hear) the air trying to come through the defrost vents but it seems blocked or not “open”. I assume this is a vacuum issue? Also I need to fix the vacuum lines I broke. But I HAVE HOT AIR!!

 

There should be a VECI (Vacuum Emission Control Information) label under the hood (usually on the bottom of the hood!) that shows the vacuum plumbing.

Also, in the FAQ, you can find a link to download the factory service manual; page 25-4 shows the vacuum plumbing (typical).

I've attached that page for you also as a PDF.

I'd HIGHLY recommend just biting the bullet, and replacing ALL the vacuum lines.

Plastic isn't too bad if you expect to replace it every 5 to 10 years; it's leaving it 25 years that makes it bad.

But your other choice - aluminum or copper - for rigid lines costs a lot more, so ...

RwP

 

Thanks. I got it “fixed”. I’ll work on replacing ALL of the vacume lines as my next project.

 

Hi guys, I wanted to throw my 2 pennies into this thread.
I had a similar problem but back flushing did nothing at all.
My buddy was reading somewhere about a guy who reversed the flow through the heater core and got good results.
I was super sceptical but damned if it didn't work... Just in time too, winter in Minnesota is no joke!
Keep safe and warm, all.