68 Delmont no coolant expansion tank

Old May 22, 2025 | 04:13 PM
  #1  
Cinnamon Gravy's Avatar
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68 Delmont no coolant expansion tank

Hello, my 1968 Delmont Town Sedan I bought this past fall has no coolant expansion tank, just a hose running from below the cap down to the bottom of the car where it randomly spits coolant onto the ground. I’d rather not be spilling coolant wherever I go so I’m trying to find an easy solution for the time being.

I can’t find much info about expansion tanks for the Delta and Delmont but there are some for the 68 442 with the 455 available that I’ve found.

I’ve heard that these 455s tend to over heat so I’ll probably have to look into radiators in the future but for now I just don’t want be poisoning peoples dogs at my car meet ups.

Anybody have any experience? Will any generic reservoir do?

Last edited by Cinnamon Gravy; May 22, 2025 at 04:14 PM. Reason: Title change
Old May 22, 2025 | 05:10 PM
  #2  
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Found a recent post with good info, think I have it figured out
Old May 22, 2025 | 05:17 PM
  #3  
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Glad you figured it out. Your 68 Delmont 88 may have never had an expansion tank. You just need to make sure that the radiator has some space near the top (about 2") so the coolant doesn't expand when HOT and belch on the ground.
Old May 22, 2025 | 05:23 PM
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I don’t think GM did expansion tanks until the early 70’s, but you’re right on - it’s not environmentally responsible to just blow glycol and whatever else onto the road going by. And that stuff is sweet and toxic to dogs and other animals.

You can get aftermarket expansion tanks for not much money, but I believe you also have to get a new radiator pressure release cap make the system work.

I used a mid-70’s Cadillac Eldorado or Fleetwood expansion tank in my ‘66 Olds 98 & Starfire, they work great and look almost factory. I use a 16lb cap and the system works great.

A side benefit is that if the expansion tank (aka puke tank) is low relative to what it was when you filled it, you’ve found a leak….

Cheers
Chris
Old May 23, 2025 | 06:32 AM
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Hi, as it’s been stated you don’t want to fill the radiator…but leave some space for hot expansion. Assuming that the car still has the original Harrison radiator and it’s not overheating and holding proper pressure…it shouldn’t really be much of an issue. I have 3 68s with 455s and original radiators and none of them puke except on rare occasions, even then it’s just a few drops. The original radiators are marked on the side as to the “full” level. Kind of hard to see but here are a couple of shots from my Delmont…I used a white grease pencil to help highlight the marking. Hope this helps. Dave


Last edited by 455Dave; May 23, 2025 at 06:36 AM.
Old May 23, 2025 | 11:58 AM
  #6  
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If you do add a recovery tank, replace the radiator cap with a later model version designed to work with the recovery tank. I think they are different.
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