Heater Core: Testing and Inspection

Eliminating Symptoms In Body Interior - Replacing Heat Exchanger

General information

Symptoms
Unpleasant air odor in passenger compartment.

Causes and remedial action
Brief unpleasant odor in the air (1 to 2 sec.) during longer idle periods, caused by heat exchanger.

In the event of a complaint, an odor test must be conducted to remedy the situation on vehicles manufactured in the specified period of introduction. Replace the heat exchanger depending on the intensity of the odor.

Dates of Introduction







Tools and materials
Heat exchanger

Replacing heat exchanger

Test preparations







1. Warm up engine for 20 min., coolant temperature at least 90°C (196°F).







2. After warming up engine:
2.1. Set air distribution to passenger blower.
2.2. Set low blower level.
2.3. Set temperature to max. cold.

3. Park vehicle, switch off the engine for 15 min.

Close windows, hood.







Remove ignition key and close doors.

Test procedure







4. Restart the engine.
4.1. Assess air flow with regard to odor, while gradually increasing the temperature.

Evaluation of odor test
1 to 2 = vehicle not usable
3 = odor no longer acceptable
4 = extremely disagreeable odor
5 = unpleasant odor
6 = odor just about acceptable
7 = slight odor
8 = very slight odor
9 = odor hardly noticeable
10 = no odor in air

Action based on score:

5. With score 1 to 6.
5.1. Remove heat exchanger.







5.2. Clean air-conditioning housing in area of inner heat exchanger.
5.3. Install new heat exchanger.

6. With score 7 to 10.
6.1. No action.