Tuesday, December 29, 2015

Replacing the Radiator and Radiator Core Support

Since I had purchased a bunch of parts for the '75 Corvette I was planning to restore (which I decided to sell), I ended up with a good selection of stuff that would fit my 1976 model.

As a side note, you need to be very careful when you purchase parts from private sellers, since parts that fit one year may not fit newer or older C3 models.

A reputable Corvette parts reseller will know this and help you get the right parts.

In this case, the 1975 Corvette radiator and core support would fit my early production '76 and that helped me save a bunch of money from having to purchase yet more parts.

Here is what the old radiator and support looked like. And even though the original core support was not that bad, repairing it would've probably cost more than buying a new one.

It is obvious that the previous owner had spray painted the core support and shroud using whatever paint he had handy. Not sure if he did this to help protect and/or beautify the area, or with hopes that a potential buyer (me, in this case) would think that the car was in great shape.

Actually, when I notice that someone has spray painted under the hood, I suspect some damage. In this case I crawled under the car and inspected the radiator core support best I could, and I could only see a small amount of rust. C3 Corvette core supports are notorious for being susceptible to rust.

This is new radiator core support after it was installed along with the air conditioner condenser, which is mounted to the core in front of the radiator. I debated about having the new support powder coated, but timing these things can be tricky. In the end, I just decided to leave it as it came from Coffman since the car will always be garaged and driven only in fair weather.

And this is the original radiator core support. Not horrible, but definitely in need of some repairs if it was to be used again.

As the close-up photos show, the bottom edge had rusted through. These parts can be repaired by welding new metal to them, but when rust is extensive, there's little good original metal to weld new pieces to. 

At the end of the day these projects are time consuming and can end up costing more than new replacement parts.

For illustration purposes, this is what a new radiator core support looks like.

I also had new rubber seals for the support, as well as new hoses.

This is the brand new radiator. It was not cheap, but sometimes getting new parts is the only option. Radiator repair shops are a rarity nowadays, and Corvette parts are expensive, no matter how you look at it.

Again, just make sure you buy the right parts for your car. If you have a car with automatic transmission and a/c, for example, the radiator has to be equipped accordingly, so the tranny cooling lines can be connected to it.

If you have a manual tranny, like my '76 does, you can plug the inlet/outlet holes.
Alternatively, you can also use an aftermarket aluminum radiator, but make sure it will fit your application without the need of many (ideally, any) modifications.

Aluminum radiators offer many advantages over their copper counterparts. They are 30 to 40% lighter; they (usually) are 100% aluminum since they are aluminum brazed (this eliminates dissimilar metal issues); aluminum dissipates heat better; you can polish aluminum for show; and more. Having said that, if you want a factory look, then an aluminum radiator is not the way to go.

As I mentioned earlier, the radiator shroud had been spray painted black, and it looked ratty. So the first order of business was to wash it thoroughly, remove all the old paint, prep it properly and give it a fresh coat of paint.
However, once the old paint was removed, it revealed a very cool "marbleized" plastic finish, which I decided to keep.

To that end, I sprayed several coats of clear after the part had been completely degreased. After the paint had cured, I applied the foam seals where it comes in contact with the support core.

I also took the time to detail a lot of the brackets and hardware. The time to do this is when the parts are off the car. I sprayed all brackets with Eastwood's Underhood Black paint since it has the correct sheen. The results speak for themselves.

And here's the radiator, core support, shroud and brackets installed. And while all this work was being done, my mechanic discovered that the fan clutch was leaking, so we ordered a new replacement radiator cooling fan from a local auto arts store.

Thank you for following my '76 Corvette Blog!


  1. Excellent article. Am working on mine and this helps a lot. Thanks


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