Oil Cooler Leak on GM 6.6L Diesel Engines - Engine Builder Magazine
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Oil Cooler Leak on GM 6.6L Diesel Engines


The oil leak is caused by minor
imperfections in the engine block machine surfaces at the oil cooler
interface that may allow engine oil seepage past the oil cooler
O-rings. To cure this problem, GM offers the following information:

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Inspect for other oil leaks that may be perceived as an oil cooler
leak. An oil leak from one of the main bearing cap side bolts may
appear to be coming from the oil cooler.

2. If the oil cooler is
leaking oil, remove the oil cooler from the engine. Use care to remove
only the five bolts that hold the oil cooler to the engine block.

3. Remove the O-rings from the oil cooler and discard them.

4. Clean the mating surfaces of the engine block and the oil cooler.

5. Install new O-rings (2) to the oil cooler (see Figure 1).

Apply sealant (P/N 97720043) to the oil cooler as shown in Figure 1. Do
not apply sealant to the O-ring grooves on the oil cooler.


7. Install the oil cooler to the engine block. Torque five oil cooler assembly bolts to 18 ft.-lbs.

8. Allow the vehicle to sit for eight hours at room temperature to allow the sealant to fully cure before initial startup.


Source: JASPER Engines & Transmissions.

For information on products offered by Jasper Engines & Transmissions, call 800-827-7455, or log onto www.jasperengines.com.

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