Faulty
Hose Composition leads to Smelly Audi
Eric Seifert, Automotive Technical
Editor
As a nature photographer, Dan racks up over 25,000
miles a year on his 2003 Audi A4 ® Quattro ® wagon. On a trip last
week, he noticed an odd smell from the car, so he stopped at a shop
to get it checked out. He was told that the coolant reservoir was
cracked and needed to be replaced. Not satisfied with this diagnosis,
he later drove to our shop. We performed a pressure test on the
reservoir and discovered that the hose between the coolant reservoir
and the engine was weeping coolant through the hose material.
If the coolant reservoir appears to be leaking,
the technician should also check these possible leak sources before
replacing the reservoir.
- May be caused by the coolant hose (1) between
coolant reservoir and radiator or the coolant hose (2) between
coolant reservoir and engine which may have internal cracks (Image
19-A116).
- Internal cracks can cause coolant to get
inside the coolant hose material and leak from connections to
the coolant reservoir (arrows) due to the capillary effect.
The following tools (or equivalents) are required
to complete the diagnosis: VAG1274 Cooling System Tester, VAG1274/8
Adapter and VAG1274/9 Adapter.
 Applicable
Vehicles
2001 to 2006 All Models, All Engines
Repair Procedure:
(Review safety procedures in the ALLDATA ® system before beginning)
Before
replacing coolant reservoir:
- Check if coolant hose (1) between coolant
reservoir and radiator is leaking at connection to coolant reservoir
(Image 19-A116).
- Replace that coolant hose if necessary.
- Run engine or drive vehicle until coolant
reaches a temperature of 80°C (176°F).
Coolant reservoir, checking for Leaks:
Remove filler cap on expansion tank.- Install tester VAG 1274 and adapter VAG 1274/8
(or equivalents) on expansion tank.
- Build up a pressure of approx. 1.0 bar with
hand pump on tester
- If this pressure is not maintained:
a. Trace and repair leaks.
b. Check if any coolant leak around coolant reservoir still exists.
Pressure relief valve in filler cap,
checking:
- Screw filler cap onto tester with adapter
VAG 1274/9 (or equivalent).
- Install hand pump and build up pressure.
- Pressure relief valve should open at 1.4
to 1.6 bar.
- Replace filler cap if necessary.
 DO
NOT replace coolant reservoir if there is no further coolant
leak detected around the coolant reservoir.
Written by ALLDATA Technical Editor, Eric Seifert.
Eric is an ASE certified Master Technician and Engine Machinist.
He is a graduate of the De Anza College Automotive Technology Program,
with 20 years of independent shop and parts store experience.
©2010 ALLDATA LLC. All rights reserved.
All technical information, images and specifications are from the
ALLDATA Product. ALLDATA is a registered trademark of ALLDATA LLC.
All other marks are the property of their respective holders.
A4, Quattro and Audi are registered trademark
names and model designations of Audi of America, Inc. All trademark
names and model designations are being used solely for reference
and application purposes.
|
