Symptom Related Diagnostic Procedures

Eliminating Symptoms In Body Interior - Replacing Heat Exchanger

General information

Symptoms
Unpleasant air odour in passenger compartment.

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

In the event of a complaint, an odour 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 odour.

Dates of Introduction

Vehicle Ident. Nos.: Model
from Carrera/RoW
99 Z6S 75 0841
to
99 Z7S 76 1335

from Carrera S/RoW
99 Z6S 76 1716
to
99 Z7S 77 3997

from Carrera/USA
99 06S 75 6528

from Carrera S/USA
99 96S 76 7055
to
99 37S 77 7341

Tools and materials
Heat exchanger

Replacing heat exchanger

Test preparations







1. Warm up engine for 20 min., coolant temperature at least 90 degrees C (196 degrees 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 or sunroof (if equipped).
Remove ignition key and close doors.

Test procedure







4. Restart the engine.
4.1. Assess air flow with regard to odour, while gradually increasing the temperature.
Evaluation of odour test
1 to 2 = vehicle not usable
3 = odour no longer acceptable
4 = extremely disagreeable odour
5 = unpleasant odour
6 = odour just about acceptable
7 = slight odour
8 = very slight odour
9 = odour hardly noticeable
10 = no odour 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.