My 740T has 177K miles. Oil dip stick is covered with creamy/oily substance. Obviously coolant is mixing with oil. Engine lacks power & smokes (white) occasionally. I presume the head gasket needs to be replaced. I am a fairly competent mechanic. Previously replaced the turbo. Last weekendI attempted to replace head gasket but was unable to loosen 14MM head bolts with my sockets..Any advise? Do i need an impact wrench? Is this job as easy as it looks?
Any tricks to keep it in time when i disconnect the overhead cam?
Thank you.

 

This is one of the easiest of head gaskets to change. Do not use an impact wrench as you will do damage. You may have to use a longer bar on the socket to get enough force to move the bolts. Slacken the bolts half a turn each in the correct sequence, then remove them. If the bolts are very tight then it is advisable to replace them as they may have stretched.

Keeping it in time is easy. Once you have the marks aligned don't turn either the camshaft or the crankshaft.

When you refit the head remember the sequence for tightening the bolts is not the same as for loosening them.

 

Thank you Bill. Would you know the loosening & tightening sequence? And the tightening torque?
Once the head is off, is it necessary to have it machined? is any gasket sealant advised?
keith

 

Thank you Bill. I am optimistic about my success on this project.

 

Loosening and tightening:



Torque settings:
Step 1 14 ft/lbs; 19 nm
Step 2 43 ft/lbs; 58 nm
Step 3 Additional 90 degrees.

Check the surface of the head with a metal straight edge and feeler gauges for warping. Usually machining is not necessary. I have never used sealant on one of these.

One point often missed is to lightly oil the bolts before fitting them.



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Edit: Oh well it's all here, just not the order I wanted.