Hi to all, I am amazed at the great advice that comes through this server. Yes, a backwards - installed fan could be the cause of the overheating on the 300L, as well as lack of distributor vacum advance. On the freeze plug ( pardon me, EXPANSION plug) discussion, allow me to point out that Matt and Jennie Allyn are referring to the cup-type plugs (since they own 1962 Chryslers) , whereas Kurt and Philippe are referring to the 1961 and earlier dish-type plugs. The later type is much, much more forgiving as far as installation, and they will not pop out, whereas the earlier, dish-type are much harder to install properly. A close look at an original cup-type will reveal how the factory intalled it. Duplicating that process using the right diameter punch is important. Chrysler did sell an expansion-type plug for these engines, which had a bolt in the center which, when tightened, seats the plug firmly in its seat - no doubt because so many replacement plugs popped out ...the part number is 2402649. I always carry a spare one of these in my 61 and earlier cars, as they can be easily installed on the side of the road, should one of the originals let go. But these are specifically made for the 1961 and earlier engines, and will not fit 62-up 413's. John