Adding radiator expansion tank to 240TD?
 

My parts car 300Td still has the radiator expansion tank which I thought I might add to my 240TD that never had one. However, the tank has a barb for about a 1" line off the bottom which, as far as I can tell, must go to the radiator on the 300. My 240 does not have an extra nipple for that purpose. Would it be better to cut the bottom radiator hose and install a "T" and use that line or just plug it at the bottom of the tank and put a longer hose into the top from the radiator overflow like most other cars use?

You would need to install a 300D radiator as well, or use the expansion tank as an overflow tank.

MAYBE, I can help. I'll be happy to send you a free w126 used bottom radiator hose. If I remember correctly the T you speak of is built into the w126 hose.

I think I have access to one of those, too.

On my w123, the expansion tank connects to the radiator in two spots, atthe bottom like the lower radiator hose, and at the top with the small return hose.

Seems like DAW has access to everything...

DAW, the fan is supposed to be delivered today...thanks again!

To me, the question is why bother? The old radiators had the "expansion" at the top of the radiator. Lots of room for coolant between the top of the fins and the overflow tube at the filler neck. The idea is to keep the coolant level just above the fins on a cold engine. The problem is remembering to keep the bottom of the overflow tube cleaned out - most folks didn't run a piece of coat hanger through there once in a while.

If you guys would just plan a day to stop in Memphis, I could show you the various parts cars around. Also, one look in my Storage Bay and you would know. And my garage....well.....it's got a bunch of parts in it, too.

Did you get your fan?

That is not the idea that caused this to be put into automobiles. The idea is that the expansion tank, being connected at the top of the system...where the air will accumulate... and a valve which will allow expansion into the reserve tank when hot...and allow liquid only to be pulled back into the radiator when cooling was the way to expel air from the entire system while providing a backup amount of coolant at the same time.
Air entrained fluids do not carry and exchange heat heat as well as liquid alone.

It also eliminates that little stream of green coming out the overflow if you do happen to get too much in there. By coincidence, the day I hit the deer with my wagon, it was warmer than it had been up to that point. When I got out to check the damage, I saw antifreeze running out and just knew from the look of the grille that the radiator was holed. Fortunately, it was only running out of the overflow.

Yes, there is just no reason to keep losing any regularly if some way to catch and reuse ( draw back in when cool ) is available...it was a great improvement....and provides instant always there reserve.... and with semi transparent ones you can monitor the coolant level without having to take off the ( HOT ) cap. I am a big fan of them as you might can tell and am planning on putting one onto my 1980 240d. I plan on making a tool holding tray on top of it just for grins.

Change everything to the 617 parts is the easiest way to go.

Fan was recieved on Friday!!! Thanks!!!!

Well, I'll stand by my comment. In America, the overflow tank was originally a response to the anti-pollution folks - the drip from an overfilled radiator was as offensive as a "smoky" exhaust. Used the same radiator, then had to go to a lower pressure cap in order for the system to work - the radiator overflow outlet was too high on the neck. Then the light bulb clicked on - the engineers could make the radiator smaller (more profit) by moving the radiator "head space" to that overflow tank. Moving the radiator overflow outlet was easy.

My old radiators don't drip as long as I keep the coolant just above the fins. No need to pull a hot cap as long as the temperature gage is working.