Advice on aluminum radiator ?

[irishman]

It has only taken 47 years but I finally have a 1964 R2 Avanti fresh from a frame off restoration and a complete engine rebuild that started from a bare short block.

BUT it overheats in the 104 degree Houston weather - fine while moving but heats up pretty quickly at idle or in stop & go traffic. The block is clean, the cooling system holds pressure, 7 blade fan works properly and I have tried adding Water Wetter. The consensus is that an aluminum radiator should solve the problem. There are several sources on the web. Does anyone have any experience with one or more of the vendors and their products? Also, several folks have said to consider an electric fan at the same time because it will aid cooling even more, remove the engine load from the viscous fan, and be much much quieter. Can anyone comment on these things? Even if the alumimum radiator did the trick by itself I would be interested in the electric fan if it really is a lot quieter but the gentleman who did the rebuild doesn't like them because of the extra amp draw. (My car already draws about 30 - 35 amps when the Vintage Air conditioner is running.)

Any thoughts and guidance will be very much appreciated!

[Gunslinger]

An aluminum radiator might help the problem but you need to isolate the root cause of the problem. Aluminum does shed heat faster and will take some weight off of the front end of the car, but it won't cure a problem that originates elsewhere.

If your car overheats, it could be from a number of sources...bad radiator cap, loose belts, bad water pump, hoses collapsing internally, slipping fan clutch, build up of crud in the block or the current radiator, etc. Just because the cooling system holds pressure doesn't mean there's not a restriction somewhere. You still have to determine if the engine is actually overheating...is it boiling over or are you going by the gauge? The gauge could be off or the sending unit could be bad.

Use basic diagnostic procedures...make sure you actually have a problem and go from there.

If you do actually need a radiator, you can have your present one re-cored with a unit that has more fins per inch. That increases the cooling surfaces by a large margin without changing the external dimensions at all. You can have an aluminum radiator fabricated which can help plus take some weight off as already said. I would only do that if your current radiator was the problem and needed complete replacement.

Electric fans can help...they can be thermostatically controlled or manually so. You may need to upgrade your alternator for the additional amperage if your a/c is drawing so much current.

You can add the Saturn air deflector under the front end...that reduced operating temperatures on my Avanti by 10-15 degrees while on the highway. It won't help at idle or slow traffic but it does make a difference.

[MikeValent]

I wouldn't normally comment on something like this, but Back in 1963-64 I owned a '64 R-2 automatic in Miami.Plenty hot there in the summertime too, but I can't remember even a hint of overheating. If yours has been completely rebuilt then I wouldn't expect to have it overheat. Is the fan original? Does the radiator have a shroud around the fan? Are you sure the viscous fan's spinning as fast as it should at idle?

For the past two years I've owned an 83 Avanti, use it as a daily driver. It has the usual Chevy 305, has factory air conditioning and a PO-installed Paxton supercharger. Equivalent engine size to yours, blower - plus air conditioner. Original radiator. It heats up to 190 degrees normally, no more than 195 just sitting in traffic. This is in Ft Lauderdale, hotter now than Miami was way back then. Mine does have an electric radiator fan (comes on at 180 degrees plus a smaller fan in front of the a/c condenser that's wired to come on with the compressor). The only time my 83 showed overheating like your car has it was because the radiator fan's thermal switch had failed.