Engine - Coolant Loss With No Apparent Leaks

Date: April 15, 2009

Order No.: S-B-01.40/25a

Supersedes: S-B-01.40/25 dated March 2, 2009

Group: 01





Revision History





SUBJECT

Coolant Loss

If you receive customer reports in the above model vehicles of a very slow coolant loss without any trace, the cause may be an internal casting flaw in the area of the valve cooling passage between the cylinders allowing coolant to seep into the crankcase. Since the amount of leakage is so small, the coolant vaporizes in the hot crankcase. The amount of coolant loss can be as little as 0.5 quarts in thousands of miles. Perform the following checks and repair instructions to remedy.

Note:
As of engine number D 273.9xx 30 270007 (approximately as of end of June 2008 production), the issue casting flow was resolved.

Note:
The cause of the coolant loss must be absolutely determined. Slow external leaks might occur as well as internal leaks, not related to the casting flow. Considerable amount of coolant in the oil pan would not indicate the casting issue. Dealers might be debited when performing incorrect repairs.

Check Procedure:

1. Inspect engine thoroughly for any external coolant leaks.





2. Inspect cylinder head spark plug recess for coolant from cracks in the spark plug hole (Figure 1). If coolant is present confirm that it is not from spillage and replace the cylinder head.

3. Fill coolant to maximum level and determine the quantity of coolant loss at the next service visit by topping up again.

4. With engine at operating temperature, inspect the combustion chambers for any coolant leakage using a boroscope.








If these checks fail to determine the cause of the coolant loss, the valve cooling passages between the cylinders (Figure 2 and 3) need to be sealed using small metal sleeves.

Repair Information:

1. Remove both cylinder heads as per WIS.





2. Clean out the six valve cooling passages between the cylinders using a pipe cleaner (Figure 4). Blow out passage with compressed air.

Note:
Clean out the passage that opens towards the intake side of the crankcase. Pipe cleaners must be sourced locally.

3. Place metal sleeve (A001 992 10 50) flared end first on a pin punch and coat sleeve with Loctite 2701.

Note:
Loctite 2701 must be used for this repair. Do not substitute with another product.





4. Slide metal sleeve into valve cooling passage using the pin punch until the sleeve bottoms (Figure 5). Wipe off excessive Loctite 2701. Repeat for remaining five passages.

5. Reassemble engine as per WIS.

Note:
Always refer to EPC for latest parts information.





Parts Information

Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on April 6, 2009. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.








In Case of Warranty, use the table above.