Reply to "Question about expansion tank cap"

You just need an old fashioned non-pressurized radiator cap for the "catch" can.

The "expansion" or "swirl tank" takes a 15 or 16 psi cap (I use a 16 but that is the safe limit of the old radiator with 50/50 anti-freeze). That gives me about a 245 degree safe limit and therefore makes 220-230 not a problem. In fact, that has a lot of benefits to it.

The expansion tank gets filled to the top. The catch can gets filled 1/2 way. It should also have an overflow hose on it. Run that down under the car so that if it does overflow at some point it doesn't spill anit-freeze all over the engine.

You should keep it as far away from the tire as you can too. Anti-freeze is slippery and that tire would spin if you overflowed while driving the car.

A couple of the Panteras that I have seen were running constantly with a couple of inches down from the top on the "expansion" tank.

It caused no problem for them. That does make sense because one of the reasons that tank is in the system is to provide a place for trapped air in the system to accumulate and not cause problems.

Some cars seem to do that more than others.

Mine doesn't but maybe that's because I was able to get most of the air out of the system and others weren't? I don't know the answer to that other than it doesn't seem to be a problem.

I do know more than a few aluminum radiators had to be replaced at about three years old due to holing through AND cracks in the tubes.

Once that happens with an aluminum radiator it's worth $.23 a pound in junk, because that's all it is.

Get a nice thick core brass radiator when you replace the aluminum. Those are repairable almost indefinitely.

The ONLY value of an aluminum radiator in a Pantera is to lower the cars weight. It DOES NOT cool better than the brass does. Anyone who tells you it does is shoveling horse manure. If you believe them then what does that make you? If you don't mind putting in a new $600 aluminum radiator every three years or so, then get what makes you happy.

The only thing is the aluminum have the damnedest tendency of "going" at the worst time and the worst place you can find. I'd rather be somewhat in control of that and at least I can get any radiator shop, anywhere to solder up the brass.