Luke warm heat 92 Eco

[92EcoDiesel Jetta]

I've been driving around with the center vent and ducts out. Kneebar and console also out atm and there is so much more room and the heat is fine other than a little too much direct air coming out the vent door. If i add a diffuser plate in front of the vent door that should redirect the flow sideways. What is the purpose of the knee bar? Does it really protect your knee in a frontal collision?

[R.O.R-2.0]

I did the blend doors in my 89 and the heat still sucks. The core must be plugged.  Pulling the airbox is a PITA. I have heard guys have split the evap section off and removed just the heater section, but that can't be any fun either.

Did you get this fixed? A quick way to tell if your core is plugged is to feel the supply and return hose. If the return is cool to the touch, the core is plugged

the INTERIOR of the core is the only thing that could be blocked..

the exterior of the core is UNLIKELY to get clogged, because it is pretty well sheltered..

the heater core is BEFORE the foam, and the foam all blows out the vents..

if your core has low flow, reverse flush it with a garden hose on as high as it will go..

then, if that doesnt work.. good luck pulling the dash!

[TylerDurden]

AIUI, the knee rail is to complement the passive belt system.  It may also provide more A-pillar strength in a side impact.


The way I figger it...
 - Loose foam can easily blow into fins of the core.
 - A core with no water flow will have two cool hoses.
 - A core with blocked fins will have two hot hoses, as the air cannot cool the circulating water.

My 89 Jetta has two hot hoses and crappy heat in the cabin. Water can flow easily through the core when i flush it.  That core probably has plugged fins.

I'm currently driving the 85/86 Jetta which has 150^oF heat at the vents. I'll pull that 89 core in the spring.

[92EcoDiesel Jetta]

I think most plugged heater cores are not totally plugged with no flow. What about a partially plugged core with limited flow? Wouldn't that result in a hot supply hose and a cold return hose?

2 hot hoses and low heat = good flow through the core and plugged fins, or cold air bypassing the heater core. Did you try using a leaf blower to clear the blockage?

[R.O.R-2.0]

I think most plugged heater cores are not totally plugged with no flow. What about a partially plugged core with limited flow? Wouldn't that result in a hot supply hose and a cold return hose?

2 hot hoses and low heat = good flow through the core and plugged fins, or cold air bypassing the heater core. Did you try using a leaf blower to clear the blockage?

the core is BEFORE any foam.. it cant get blocked by foam chunks..

the blend doors have broken windows...

[TylerDurden]

the core is BEFORE any foam.. it cant get blocked by foam chunks..

Dude, I have four of these. The temp mixing door can block air from the core - therefore it is before the core when moved into the Cold position. 

[92EcoDiesel Jetta]

the core is BEFORE any foam.. it cant get blocked by foam chunks..

Dude, I have four of these. The temp mixing door can block air from the core - therefore it is before the core when moved into the Cold position. 

Tyler speaks the truth! There's not that much foam on the blend door though, IMO not enough to completely clog the heater core fins to the point of no heat. Maybe mice built a BIG nest in there? Do you have AC? If no AC, if you take the blower out, can you look at the blower side of the heater core with a mirror or borescope to see what's clogging it?

[TylerDurden]

I do have the AC evap in there still, but a flexy scope/cam is a good idea.

I got bigger fish to fry on that buggy tho... gonna pin the crank/pulley before anything else.