The Stovebolt Site Forums The Shop Area The HiPo Shop Isolators for Aluminum Radiator - 52 3100

Planning on installing an aluminum radiator on my 52 3100. The manufacturer calls for isolating the radiator from the radiator frame as a means of reducing vibrations to the radiator. I tried a rubber washer that is .12" thick and that just does not seem robust enough (see enclosed picture). Some people have sugggested that I need to add a metal washer to front and back of the rubber washer in order to achieve acceptable levels of isolation. I also searched McMaster web site for appropriate isolators but did not find anything that seemed appropriate.
What ever solution is seclected, I am trying to keep the distance from the radiator mounting fins to the back face of the radiator frame, to a minimum.

I could benefit from the experiences of others who have successfully navigated this path, or who have knowledge of how to achieve effective isolation of radiator from radiator frame.

Thanks

I drilled out the mounting holes a hair bigger and put rubber grommets in with a washer on the backside.

The goal of the isolation is to keep the frame flexing from stressing and cracking the aluminum.

If you do use rubber washers like you show, put one on each side of the radiator so there is no metal to metall contact.

Assuming you are flange mounting the radiator and not knowing what about the rubber washer was not robust enought....

If you don't like 1/8, stack two of them. You may want to use a nylon lock nut so as to get the right rubber squeeze/isolation effectiveness. If you torque it all down, you take out the cushion. Don't over worry about this. The welds on the radiator mounting flange are strong. The truck has suspension and rubber tires. The two hoses hold it also.

The only slight protection issue is a large shock load. NOT "vibration". I don't know how the original radiator was isolated. I see pads available for AD.

I don't believe the original AD radiator was isolated at all. If it was, whatever was there was long gone when I removed my radiator last summer.

The original radiators were not isolated, but they were ductile copper not aluminum.

The issue is not the vibration of the radiator itself, but it flexing. Aluminum fatigues and cracks very easily.

If you look at any modern vehicle that comes with an aluminum radiator from the factory, they all have rubber isolators even though the newer frames/core supports are much more rigid than the old ones.

Thank you all for offering perspective and possible solutions... this is what i think I will try, since I am trying to keep radiator as far "forward" (away from the engine) as possible...

I am going to use the 1/8 rubber washers that I have today, but I will create a "sandwhich" of (metal washer, rubber washer) in front of the radiator mounting flange and (rubber washer, metal washer) behind the radiator mounting flange, that will solve the "mixed metals" issue (aluminum in contact with steel) as well, except of course, for the steel bolt going through the entire stack.

I'd suggest making some BIG rubber washers by using a hole saw on the sidewalls of a junk tire- - - -and sandwiching them between a couple of fender washers- - - - -those flat washers about three times the diameter of a normal flat. Use the biggest diameter washers the radiator mounting flange will allow to spread the load out over a wider area.
Jerry

“Baler belting” at your local Tractor Supply or farm store is awful handy for making isolators and cushions of various kinds. It’s reinforced well and holds up. A 4" x 5' strip will last a long time.

My aluminum rad in my 49 gmc has been solid mounted since I built it in 2019. No issues. The actual rad frame is still rubber mounted with spring bolts to the frame but I dont see how the rad frame should ever flex. I wouldn’t get to crazy worrying about it. Toss some of those rubber grommets with a steel spacer in the center on it if your really that worried.

If your rubber washers are too soft, you may actually INCREASE vibration at the radiator mounts. Vibration is a weird thing. I think I'd be more comfortable with solidly mounting the radiator to the core with maybe the exception of some thin material to isolate the aluminum from the steel. You might find nylon washers with a sleeve to isolate the bolt from the hole in the radiator. Your truck being a 1952 it should have the more rigid radiator support with cross braces.

Frequently the cross braces were cut to allow the engine/transmission to be removed together.

The manufacturers of replacement aluminum radiators should be designed and made for the application and state if special mounting hardware is needed beyond stock. I found a high end aluminum rad to cure over heating issues on one of dad’s 58 Chevys with a 327 and it did state to just use the stock mounting hardware. No issues in 8 years.
And as others have said, if it’s too loose it can also cause destructible vibrations.