Radiator shop rebuilt 40 Buick radiator now have a problem

michel88 · May 27th, 2009

I had a radiator shop recore my 40 Roadmaster radiator with a 4 row core to help cooling. They also put on a new filler neck. After installing the radiator I found that the new neck is too deep for the cap to make contact. It will shoot out water after a drive now because it is not sealed or under pressure. The neck is 1-1/8" deep instead of the standard 3/4" deep neck. I haven't had any luck finding a radiator cap that extends deep enough to seal. I would like to avoid removing the radiator to put on a standard neck. Does anyone know of a radiator cap that would work with the deeper neck?

critterpainter · May 27th, 2009

Are you sure its 1 1/8"? I know that Buicks from 1940 through 1947 uses a deeper neck than later years but I thought it was 1".
These caps are available from Bobs Automobilia 805-434-2963

michel88 · May 27th, 2009

It does measure 1 1/8" but I think it was an oddball neck that they installed. I wish they had left it alone. I did get the cap from Bobs but it's not making contact with the surface. Thanks for your reply.

Bhigdog · May 27th, 2009

How about making a 1/8" thick fibre or rubber washer to take up the slack? Mcmaster-Carr has a number of suitable materials at small cost. Just a thought......Bob

michel88 · May 27th, 2009

That is a great idea that should work. The spacer would partially obstruct the hole for the overflow, but about 2/3 of the hole would be clear. I am going to look at McMaster and see what I can find. Thanks!

Bhigdog · May 27th, 2009

They have several silicone rubber compounds good for 500 deg. F. for as little as around $7. Check the beginning of the section for an explanation of Shore hardness if you're not familiar.......Bob

imported_BUKE · May 28th, 2009

I had the same problem you have with my radiator shop when he recorded my 1940 radiator he changed the neck and had the same problem you did. When I brought it back to him he replaced it without taking the radiator out it talking about a half-hour. Later I found the right cap On eBay I might have another one in my garage if you can't find one let me know and i will ship it to you if I can find it.

Frank

michel88 · May 28th, 2009

I went to several auto supplies and NAPA was very helpful but could not get a cap that would work. I would be very interested if you can find the cap in your garage and it would work with a 1 1/8 deep neck. Thanks for your help Frank.

imported_BUKE · May 29th, 2009

ok i will get a chance to look very soon and get back to you

imported_BUKE · May 29th, 2009

Well that was fast sometimes I think I know what I'm doing. Well I found it and it's yours for the address to send it to if it fits it and works for you keep it it cost me $24 on eBay I tried it once a long trip and it worked well. It's still in the original 1940 bucks I believe but if it doesn't work please send it back I will ship as soon as I have your address. Please send no money to your sure it works.
Have a greatBUICK day
Frank