Disastrous short-cuts
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frame, and this was traced to a copper heater pipe, where a loose hose clip was resting. It was then found that the nick in the pipe resulted from the fretting of the clip, which, of course, the mechanic had not bothered to cut free. And that was a very costly oversight.
Another area where shortcuts can create problems is where one cover mates up with faces on two castings, and these faces must be in line— as in a water pump/thermostat housing that fits against the front of the head and block.
Head and nuts
Too often, the mechanic fits the head and nuts, torques them up, and only then turns his attention to the water pump housing. If he is in a hurry, he will probably not notice that the head face is, say, 0.02 in out of line compared with the block face, and he will only find out when the water starts to leak, and to put that right, he has to loosen off the head nuts.
Whenever a cover spans two castings, it is essential that the faces are aligned correctly before they are assembled. The best way of doing this is to tighten the cover, without a gasket, to the faces before the nuts are tightened. That way you can be sure that alignment is spot on.
Don't forget to remove the cover, and refit it with its gasket, or you'll have a leak on your hands anyway. But the point is that there is often quite a bit of clearance on the main fasteners, and even dowelled heads need watching. This is one of those cases where a bit of old-fashioned thoroughness pays off.