Radiator foam inserts

Hi guys
Has anyone found a supplier or have a foam spec for the Foam that stops the air leaking past the rad into the bay?.

Hi Mike,

To cover the gap between the condenser coil and radiator, I used foam tape which you can get at a hardware store. Typically used for sealing windows, Window A/C units, etc in your house.

Last night I was perusing Bernard Embden’s write-up on his radiator install and noticed a pic of a big blob of foam to put between the radiator and the body. Now I have to run out and peak under the hood to see if I have this giant gap to fill.

Scroll about a quarter of the way down or just search for the word “foam” and you will see a pic of him holding the foam. To me it looks like nothing fancy. Perhaps the foam you can get at a craft store for cushioning seats.
Maybe others have more knowledge on this and can share.


Just get some pool noodles, preferably in a color to match the car.

Seriously, don’t do that. They probably melt or burn at ten degrees above room temp.

When you’re packing spaces, be sure to pack the opening between the top of the oil cooler and the bottom of the A/C condenser. It’s only perhaps a half inch wide, but it’s very important to plug it up.

And don’t get melamine foam; while it ages well and is very heat resistant, it is abrasive. Black or grey open-cell foam… HVAC supplies or construction? PUR foam (acoustic, or construction… it must survive 100°C).

Magic Eraser?

20 char

Yes, will eat the paint and hold water, but so far hasn’t rotted anywhere (there is an adhesive variety). I used it on exhaust to body noises and successfully to temporarily keep heat shields from rattling.
Dirt cheap too! I have a few square meters I saved from the bin. Very useful, just not on good paint.

I choose to use closed cell foam, as open cells is a water trap
I got a sheet from ebay which I cup to shape / size
I forgot to take in account the mower compression capability of the closed cells so had to cut the strips by half to reduce their thickness

not the same seller, but similar product to this

Thank You gents for the replies, I have managed to save the foam that was purchased on the original rebuild 15 or so years ago, I soaked the two outer foams and they came up clean and OK and will definitely work, the top one will get a clean as well.

It is nice to see a picture of them. I did not know the top foam piece was part of the original build.
I will need to see if there is any gap there. I assume this goes between the radiator and the upper support?

I think it does, at least that’s where it was, although following Kirberts insightful knowledge, I did offer it up between the oil cooler and where the air conditioning condenser sits , It’s looks ideally shaped and sized for this task… I shall use that one for that purpose and I’ve got a good length of 1” X 1/2” just by chance that looks/feels almost identical and shall use that for the slam panel/rad.

Let me know if you need more photo’s

I’ve got the pictures of the old ones I took out whith the rad so I could have it checked and refreshed
the sides lookeds like the 2 upper one on the above picture, some areas being totally crushed by wiring or pipes
upper one was like the lower one on the pic, with 2 square cuts for the radiator fixings
a similar one was at the bottom of the rad

and there is an additional bit glued to the crossmember below the rad, to block all airflow

cutting the replacement stripes from the foam sheet

Interesting, I only got three bits of foam with my kit… the side and top or bottom…

my car is a 1993 6.0L (early ones, MY 93.5) if this could make a difference

the lower bit is a much stiffer foam than the 4 around the radiator

It is much more sturdy than the other foam strips. I’ve replaced a number of radiators and never had to bother changing this bit.

agreed : it looks like closed cell foam, while the others are open cell, and much softer

I only took it off in order to fix some corrosion spots nearby,
I fitted it back after the respray

Coupe, you couldn’t draw us out a rough diagram of the bottom foam could you?? I wont hold you feet to the fire on the dimensions… I don’t have stiff foam just the open cell low density sections for the top and side…

This any good to you?

better than my picture :smile:

@V12-Smig : open cell foam won’t do here, as it’s not compressed against anything,
this bit of foam is the only thing cutting airflow below the radiator, so need to be rigid

so my Series three V12 has different bottom layout to yours Cosmo, in any case I test fitted cleaned foam and used some open cell foam that compressed nicely between the bottom of the radiator and the top of the slam panel, not sure if you can see it on these photos