How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Jake Your Own Question
Jake
Jake, VW Technician
Category: VW
Satisfied Customers: 2427
Experience:  Over 30 years experience with VW, Audi, BMW. Factory trained, former Shop Foreman, Service Manager
9204914
Type Your VW Question Here...
Jake is online now
A new question is answered every 9 seconds

i have a 2003 passat heater does not work took to shop they

Customer Question

i have a 2003 passat heater does not work took to shop they inspected climate control. checked all codes,tested flaps,tested all wiring for positions.found no flow or minimal flow in cooling system. they recommend removing waterpump to inspect impeller. what do you think.   thanks
Submitted: 7 years ago.
Category: VW
Expert:  Jake replied 7 years ago.

Hello,

 

Thank You for choosing Just Answer for your query. Yes, I can help you.

 

Does the engine temperature gauge get up to normal operating temperature? It should be straight up, or half way. If not the thermostat is stuck open or opening to soon and must be replaced. This is a COMMON occurrence on this year model.

 

The impeller coming loose is NOT common on this year model engine. This usually happens on the 1.8 turbos. When the impellers do fail, they overheat. Is your vehicle overheating?

 

If the engine temperature is correct your symptoms are consistent with a plugged heat exchanger or heater core. This is a VERY COMMON condition for this year model VW. There is NO valve in this system to restrict coolant flow to the heater core.

 

The amount of flow going through the heater core is very hard to determine and the apparent resistance can be deceiving. If you try and remove the heater hoses and check for flow, you will not be able to determine the "flow" as the coolant is "drawn" (sucked) through the core by the water pump. This way there is flow through the heater core even before the thermostat has opened. If you run water through the core or blow through it, it may appear not to be restricted, again "deceiving".

 

The core of the heater core is not only a group of tubes, but the tubes are filled with a mesh material similar to steel wool. It takes very little resistance to overcome the low pressure from the engine. On a properly functioning system the temperatures of the two heater hoses is typically fairly close with only a slight reduction in temperature. Typically when I replace restricted heater cores the coolant often appears perfectly clean. When I cut open the core and then it has a chance to dry out, small particles consistent with the appearance of sand are found in the mesh material.

 

I suggest you try to confirm the core blockage as follows. Fully warm the engine to operating temperature. Shut down the climate control system so that no air flows through the system. drive the vehicle at slow speeds or run at an elevated idle for a few minuets. turn on the defrosters at maximum heat. If the heat appears hot at first, but then rapidly diminishes, the core is likely the cause. If however there is no heat a heater valve (if equipped), temperature blend door, or sensor may be at fault.

 

If there does appear to be a restriction in the heater core to further confirm, you can try back flushing (flushing backwards) the heater core with a water hose. Observe the expelled water, especially in the beginning, for any evidence of contamination. This may also give you increased performance, but typically will not be 100%.

 

Note: This condition and testing is based on the fact that the engine is getting up to proper operating temperature. Straight up or ½ way on the temperature gauge, 90c (190 f).

 

I hope this helps clarify the problem and aids in your diagnosis. Should you decide to accept my answers please click the ACCEPT button.

 

Stay warm!

Jake

Jake, VW Technician
Category: VW
Satisfied Customers: 2427
Experience: Over 30 years experience with VW, Audi, BMW. Factory trained, former Shop Foreman, Service Manager
Jake and 3 other VW Specialists are ready to help you
Customer: replied 7 years ago.
Relist: I prefer a second opinion.
Expert:  Danny replied 7 years ago.
He's speaking the truth. I've never once seen a V6 impeller brake on the waterpump. Plugged heater cores are very common so run the car and check to be sure that both heater core hoses are hot and not just one of them. Also do his heat test that he spoke of. I think it's probably a plugged heater core as well.

Danny
Customer: replied 7 years ago.
Relist: I prefer a second opinion.
Expert:  Danny replied 7 years ago.
You've had two opinions already, the next person is going to tell you the same thing because it's what's wrong with your car. I'll opt out so somebody else can post in here.
Expert:  David replied 7 years ago.
Hows about a third, The answer on the water pump is dead on, the V6 do not have the issue that the smaller 4 cyls have. The problem with your heater is going to be a plugged or restricted heater core. This is a very common problem with both the Passats and the Audi A4. You will need to have the heater core replaced if you want to have your heater working correctly. I have worked for VW for a long time, and have seen a lot of issues with the heater core. It has to do with the location, the heater core is higher then the engine, and the hoses go up and over the cowl, this causes the heater core to be unable to remove and sediment from itself and over time will plug up.