How to find VW Audi Coolant Leak - Antifreeze Leak - V6 2.8L 2.7T V8 4.2L
SERVICE BULLETIN: Audi VW V6 and V8 Water Pump Coolant Leaks
Download PDF - Subject: Correctly diagnosing coolant leaks discovered soon after a timing belt kit has been installed.
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Subject: Correctly diagnosing coolant leaks discovered soon after a timing belt kit has been installed.

March 17, 2014

Application: Audi VW Water pumps for V6 and V8 Engines: 1992-2007
Part Numbers: GH21110, GH21111, GH21112, GH21113, GH21116, GH21117, GH21118, GH21119, and GH21132 Timing Belt Kits (Enhanced and Enhanced +)
Release Date: 03.17.2014

Customer Complaint: "I have a coolant leak. My water pump is bad. I used your timing belt kit. What are you going to do?"

We understand the frustration our customers feel when they have a coolant leak soon after installing one of our BLAU Timing Belt Kits.

Often when problems arise, such as a coolant leak, the new water pump is blamed as the cause. Please do not be quick to assume it is the water pump. Blauparts supplies the highest quality, factory-tested water pumps manufactured by Graf Italy, an O.E. component supplier.

There are several steps in determining the cause of the coolant leak that should be followed before a 'defective' water pump diagnosis can be made.

Please have your ASE certified Audi VW mechanic verify the following:

1. Remove your Audi Vw splash pan from the bottom of your car.
2. Confirm what location the coolant leak is coming from e.g. front, middle, back of engine.
3. If it is NOT dripping down from the front of the engine or the front of the engine oil pan it is NOT the water pump. Check for coolant hose leaks behind the engine or below the coolant fill tank (a.k.a. expansion tank) etc.

If there is leakage coming from these front areas, continue with the next step of inspection:
1. Run the engine and bring to operating temperature. Answer these questions as you observe the engine running:
- When looking at the front, is the coolant dripping continuously down on the front of the engine the front of the engine oil pan while car is running?
- How significant is the coolant leak?
- Is the coolant just residue that was captured in an engine block crevice or cavity from a coolant spill when the old water pump was removed?
2. If the coolant is dripping continuously while the engine is running, put the vehicle in the service position. Remove the serpentine belt and both timing belt engine covers to inspect the following areas.
IMPORTANT NOTE: At this stage, please don't be quick to assume the Audi VW water pump is bad. It still could be one of the three common reasons noted in the following section.

Check the thermostat housing for leaking:
1. On some models this housing is made of plastic. There may be a hairline crack, almost invisible to the eye, that has developed due to the cover being removed and then reinstalled during thermostat replacement.
- Was the thermostat installed in the right direction, not backwards?
2. If the thermostat was installed backwards, the thermostat will put uneven pressure on the thermostat housing causing the o-ring not to seal.
3. Another thing to check is the thermo housing o-ring. Was the o-ring sealing grove on the engine block cleaned properly and was all previous build-up of calcified mineral scale removed from the o-ring sealing groove. Many mechanics are in a hurry to save time in repairing your car and over look these details as noted in our step by step instructions.

Inspect the perimeter area of the water pump for leaks:
1. Check the gasket seal on the water pump itself to see if coolant is leaking from around the perimeter of the water pump.
2. Note that a fiber gasket was included with your new water pump for sealing in between the pump and engine block.
- Was rubberized RTV gasket sealer used on engine block, water pump, water pump gasket, or thermostat housing gasket mount?
IMPORTANT NOTE: Some mechanics use RTV gasket sealer in conjunction with the fiber gaskets as standard procedure. However, this is wrong! In most cases, using such material will cause a coolant leak at one or multiple locations on the gasket sealing area. Professional mechanics are trained to not use this material. It is important to pay attention to and follow our instructions, along with the manufacturer's installation instructions. Sealing agents (RTV Form-a-Gasket silicones, aerosol adhesives or sealants) should not be used. Professional mechanics will spend the extra time required to properly clean the water pump gasket and thermostat o-ring surfaces thoroughly, rather than using RTV sealant, a "quick fix solution".
3. Regarding how to perform the important water pump installation and repair steps mentioned above, see our video link below on how to properly install an Audi VW water pump.

Finally, check the water pump 'weep plug' hole: (See attached IMAGE)
1. The weep plug hole is located behind the water pump pulley and may be covered with what looks like a silver round disc. The pumps we send out say 'Tested' on the silver disc. They keep contamination out of the 'weep plug' hole. For information on where to find this water pump weep hole, please see the information linked below.
2. It is not uncommon for a new water pump to have some slight leakage or seepage of coolant from the discharge hole (weep plug) below the water pump pulley shortly after start up. This is because the unique seal material in the new water pump is designed to "bed in" as the impeller shaft spins.
3. Slight weeping or dampness from or around the discharge hole, or the silver metal disc covering the plug, is allowable for at least 100 miles after installation and should not be attributed to a 'defective' water pump.
4. If the leaking keeps on after 100 miles, THEN you probably have a defective water pump. This is the only true sign of a 'defective' water pump vs leaks that are due to improper surface prep or installation errors. If the weep plug is leaking there will be corrosion and leakage around and under this small silver disc. Call us for immediate warranty replacement.

Phone: (920) 758-3232
Fax: (920) 758-3234
Hours: Mon-Fri 9:00AM to 5:00PM CST
Copyright BLAUfergnugen! Inc. 2014

To learn more about common water pump leaks and tips on how to properly install an Audi or VW water pump see our illustrated info page.

For information on where to find the water pump weep hole click here.

Click here for BLAU Timing Belt Kits.