A fix for stripped threads on a 617 oil cooler.

[P.E.Haiges]

The oil cooler on the 617 engines is all aluminum. So sometimes the threads on the cooler and the steel nuts on the hoses diffuse together. When the nuts are turned to remove the hoses, the soft aluminum strips off the cooler thread and sticks in the nut, thus making the cooler unusable.

Since the coolers are very expensive, a fix can save a lot of money.

Here's how I did it: I had an extra cooler that leaked so I sawed the threaded nipple off and had it TIG welded onto the cooler that didn't leak. I cut the stripped nipple off next to the hex section so the two hex sections could be welded together This is because there was more parent metal in the hex section to weld to. Cost to weld was $10 and well worth it.

To remove the aluminum from the threads in the nut, I heated the nut, rapped it and most of the aluminum flew out. Then I scraped out the remainder. The heat broke the bonds.

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