not much heat

[jettabrendan]

My mk2 has no heat, both heater hoses get hotl so I'm assuming the heater core isn't plugged. Blower works great, but the air is barely warm. Sorry for vague info but its all I got.

[rabbitman]

I'm not an mk2 expert but I've heard the "doors" inside the heater box can leak and mix hot and cold air, do a search there's been lot's of talk about it.

[maxfax]

Rabbit man has got it..    THe blend doors are essentually a piece of sheet metal that look like swiss cheese..   Then they are coated with foam rubber..   The foam rubber turns to dust and the swiss cheese doesn;t divert air so well..   An easy fix is to remove the lower duct work and reach up in there and cover the thing with duct tape..  Although the duct tape doesn;t last so long..  I opted to glue pieces of plastic to the door (sides cut out of an antifreeze jug no less).. Works dandy....

[jtanguay]

i'll third the blend door problem. after my heater core blew the anti freeze turned the foam into dust. if you want something a little more permanent and long lasting, use the aluminum tape used for duct work. i myself have used foam i bought at the dollar store and some 3M spray adhesive, but we'll see how long she lasts! check out my thread in the FAQ

i would also recommend flushing out your cooling system as that really helped me out! (much much more heat!)

[JBG3]

I have pics to relate to this issue, I just got into this extensively-

Heater doors foamless and swiss cheesy-

[TylerDurden]

+1 on the metal duct tape.

Putting the tape on is a PITA, but much easier than pulling the airbox. It helps if you have dainty hands.


The door in the back is the hot/cold control.





You may have noticed dark flecks of debris coming out of your vents - that's the old foam. I'm not sure how much gets stuck in the core, but I bet it's significant.

[srgtlord]

I used lots and lots of duct , regular duct tape 4 years ago....

[ToddA1]

That looks like the same heater box that's on my B4 Passat.

http://forums.tdiclub.com/showthread.php?t=364026&highlight=Heater+box

-Todd

[TylerDurden]

That looks like the same heater box that's on my B4 Passat.  http://forums.tdiclub.com/showthread.php?t=364026&highlight=Heater+box

It looks the same to me. Kudos on that b*tch of a job.

Was there foam stuck in the fins of the core, or had most of it blown out the front?

[ToddA1]

The core is before the foam, so the foam blows out the vents.

-Todd

[wdkingery]

Shut up Yall mean I could have considerably more heat!? 1985 I bet I got a case of the cheeses too!

[quanstrom]

I have an '85 which I bought without noticing the inlet and outlet water hoses to the core "teed" together.  It was a cold ride home that night...

I pulled everything apart and used sort of a duct tape method to restrict all air through the holes last year.  The car is capable of cooking a pot roast in the back seat if the blower switch is on "4" now.

[TylerDurden]

I had a blinding flash of the obvious today...

My 89NA Jetta was taking a long time to warm up and get heat to the cabin. (I've done the tape on the airbox doors and flushed the core.)

But, while running a can of cleaner through the IP, I realized the radiator fan was running because I had the selector in the Defrost position. The AC has not worked since I bought the car, so I took the condenser out last year when I loaned the car to my pal in Miami, to let as much air flow to the radiator as possible. Well the rest of the AC stuff is still there, including the wiring that energizes the fan when the selector is in any AC position, including defrost. (Strangely, the AC relay normally on the fusebox is missing.)

My solution was to undo a connector in the engine-bay (no need to get into the dash mess). The double connector by the battery has R/W and G wires. Disconnecting that retains the thermostatic switch function for the fan. In the summer, the connector can be re-connected to allow forcing the fan on for extra cooling.

My other 1.6s have piping hot air from the vents: ~150F, this car only about 110F.  Oh well, I doubt I'll replace the core... I don't plan on keeping this car after the winter passes.

[damac]

I had to do the heater core on my 85 last week, getting dangerous to drive without one and cold

Mine was just like the pics, no foam on doors, worn out bits on vent flappers.

I decided to take the route of taking the dash out and thats the way I would do it in the future even though I have seen people mention doing it with it installed.  This way I could easily move things around and refresh all those doors.

I don't have ac on my jetta, but it was rather easy to get to all bolts with a small ratchet/socket setup.

[tyb525]

So if my vents are open with the fan on and cold air blows out of them even when I'm stopped, and hot air blows out of the dash vents, is this because I'm missing the foam?