355 Heater question

i finally have my hyacinth pump and air divertor motor working. I am bleeding the system and have the car up to temp with the heat on high but no hot air coming out of vents. The hoses into and out of the pump going into the evaporator are hot, but the hoses into and out of the water valve that controls heat are cold. I can see the valve working as I turn the interior temp switch from cold to hot but hoses remain cold. How do the hoses run.? I had the replaced at my engine out. Could the hoses under the car be reversed? How does the water flow after leaving the engine to the evaporator?

 

Image Unavailable, Please Login

 

I think either I have a blocked return line or a blocked heater core.

 

Could the driveshaft for the butterfly on the valve be broken in the closed position? I don't know how long it would take for the hoses to get warm with no flow. It has been known for the shaft to break.

 

I tested the valve before I put it in and the valve turns and you can see the hole open and close. Wondering if heater core is blocked? Going to take off valve and run hose into a bucket and see if water is getting for to valve. They put on all new hoses so possible hoses running underneath are connected incorrectly?

 

Looking at the parts manual, I think it would be hard to cross the pipes up.... The pipe shapes look quite specific.

Here's a diagram I pieced together...

HVAC water recirculation path

 

Will check 38 and 41 hose to make sure those are not switched. If ok then remove 38 hose from valve, run car and see if get any water out of hose. If not. I can only think heater core is blocked. Both hose in and out of valve are cold when heat is on.
Does outside temp matter as far as how much hest comes out vents?

 

As you have verified that the valve is opening, I would next check whether the electric pump is actually moving water, either on a bench or by your suggested hose and bucket method. You should get a fairly strong jet of water from the hose.

The motor may be turning but the pump impeller may not (impeller seized and the coupling to the motor shaft broken). Another possibility is that the pump motor is connected with opposite polarity in which case the impeller will not move any water. This, of course, will not be the case if you have not touched the pump motor's connector.

 

I see the wiring diagrams call this pump a "water recirculation pump at idle". Do you know if it's only active with the engine at idle? Would the main pump be able to force water past the impeller of the recirc pump? I don't see any input from the tachometer system.

 

The recirc pump is designed to work with low engine rpm and assist the hot water flow in stop start traffic or standing. The engines water pump will push water through the matix even with the recirculation pump disconnected electrically.

 

Was feeling the hose that runs under the expansion tank. It is completely kinked.
They must have done when they did engine out. Hose must be 90% closed

 

crazy... all that worry... hope they do a better job next time... Was it an independent or dealer?

 

Independent. One of the biggest Porsche race shops in the country

 

Replaced the crimped return hose to the bottom of the overflow tank, now have heat and now have a completely working HVAC system. Had replaced the chips in the ECU so for the first time in 6 years, everything is working!,