Radiator in a DC

I'm thinking about putting a new core in my DC
, there are some on Ebay that are well priced .
The question is , do those 2 big screws on the
side of the tank have to come out ? That would
be a real challenge ...

Both sides and top and bottom tanks need to come off. Lots of 5/16 bolts to twist off. Heat them up with a torch, it helps some. By the time you are done you will be pretty good at drilling and tapping the broken ones..DCs really cool good with a new core.....BTDT.

Beware of buying the lowest cost radiator core. I learned the hard way. You might get only 3 rows of cores or 4 rows with undersize ovals. Ask the Ebay supplier for an end view of the core. The DC needs 4 rows of cores with "standard ovals".

For the bolts without nuts, I would heat the head to a dull red and keep it that way for 2 or 3 minutes. This will allow the red heat to penetrate far into the threads and break the rust in the threads. Let it cool and then try working the head loose and tight to get it to free up.

If a bolt twist off flush, I plug weld a washer with a hole the size of the bolt to the broken threads. The broken treads experience a molten temperature rather than red temperature. I then plug weld a second washer onto to the first washer and pile the plug of weld high. This double heats the rusted threads very hot. Then using a pipe wrench or vise grips on the od of the washers, I find the broken threads usually come out quite easily.

Why use washers rather than a nut to weld on? A thin washer allow the weld arc to stay on the end of the broken bolt. Using a nut, the arc is more apt to quickly jump to the side of the hole in the nut resulting in a poor weld onto the broken bolt.

Ok , thanks guys for your advice.....

They really aren't too bad to drill out and retap. I usually grind the heads off the two on the top. You have to be really careful to not hit the casting with the grinder. I also am cheap enough to make my own gaskets. I think I have done 3 cores so far.

I agree with Ron SA. I just did a Case c radiator and broke all seven blind bolts. I welded a washer first, the welded a nut (any size that you can get down inside of to weld. then screwed them out with a wrench. take your time and keep rocking them back and forth a little at a time. Good luck.