One of the most frustrating things about this engine swap I am doing is when I got it all back installed and started to add fluids, anticipating the big moment of restart, while the coolant is going in, I see drops on the garage floor. The radiator is leaking. The radiator was probably marginal and all the extra jostling finished it off.

So, I bought a new radiator. A new one without any of the foam rubber surround. The foam as you may know is necessary to control the airflow and make sure it all gets pushed through the fins of the radiator, or else it will largely bypass it. That would cause overheating at best, other failures at worst. I need to add the foam rubber surround to the new radiator.

In some cases you can just reclaim the old foam from the old radiator and reuse it. I'd like to do that but in my case it's too dilapidated to reuse. The left side is soaked with transmission fluid from disconnecting the heat exchanger lines anyway and probably won't stick with or without glue.

To make a new foam surround for the new radiator, I used open cell foam typically used to seal around window air conditioning units. It comes in various sizes at home improvement stores.

The one I used comes in about a one meter length with a square cross section of about 6 cm a side. I used a pair of scissors to cut the pieces to length, one I can use for the top and bottom and a second length that will fit the sides.



I need one each for the top and bottom (same length) and one for each side (one for the left and one for the right, same length). So I cut both pieces lengthwise to make four pieces, two long and two short.



I used 3M brand 77 spray adhesive to glue the foam to the radiator because I had it. I'm sure other types would work.




The side tanks of the radiator for the X-type are not square, however the radiator frame on the car is square, so the foam needs "squared up" to fit. Once I got the foam glued on the top and sides I trimmed the side foam approximately along the white lines I added to the next picture. Save the trimmed foam.



I also had to trim the foam along the bottom or it will block half of the transmission heat exchanger.



Check this in the car once you get it installed. I had to cut even more foam from around the transmission heat exchanger once I got it all mounted in the car. You don't want to block that airflow for the transmission cooler. I image there'll be a big penalty for that if you do.

Finally, I used some of the foam trimmings from earlier to fill in any gaps.



All done. Radiator is filled. There are no leaks. Now, if I could just get the engine to start!

 

Update: Car is running now, no coolant leaks!