The Stovebolt Site Forums The Shop Area Driveline Mechanical cooling fan

My 49 3600 with a 216 needs a little help cooling. Installed aluminum radiator the engine temperature is generally stable however on a very warm day sitting still at a traffic light it quickly wants to get to very high temp. After moving a half mile or so it cools right down. On a cool day, under 70°, it performs well virtually all the time. Seems to me it just needs a little more airflow. Can anyone recommend a high-performance mechanical cooling fan that will fit the engine? There’s plenty of them out there a couple that I have looked at and tried simply don’t fit. Any help would be much appreciated! Trying to avoid converting to electric cooling fans if possible. Thanks!

Define "very high temp"- - - - - -is the coolant boiling? Original equipment temp gauges can be notoriously inaccurate, often indicating in the "hot" zone when the coolant is only moderately warm. The new radiator will allow you to use a pressure cap that will allow the coolant to get above 212 degrees without boiling, but only if you also upgrade the heater core to handle the increased pressure. Most original equipment heaters in good shape will handle a 7 pound pressure cap without any damage, and that will allow the coolant to reach 233 degrees without boiling over.
Jerry

I've been putting over 100 miles a week on an unrestored 216 with the original radiator, 4 blade crank driven fan, and no shroud. It never overheats or vapor locks or anything of the sort. This includes rush hour traffic in downtown Atlanta.

I was driving this truck in the summer with temps well into the 90s without a blip on the temp gauge and without any overheating. Factory gauge stays at 180 or just above. Who knows if it's accurate, though?

The truck has an overflow reservoir that works perfectly - filling up when the engine is hot and returning to the radiator as it cools down. I use a 4 pound pressure cap.

If your truck is overheating , it isn't due to poor airflow. You have other issues to sort out.

Jerry's right, though. If it isn't boiling out as steam all the time, your engine probably isn't overheating.

Install an overflow reservoir for peace of mind. This truck already had one installed and I elected to keep it. You can fill the radiator all the way up to the top of the filler neck instead of 2 inches below the top of the tank.

When the temp rises in traffic, are you experiencing any other problems associated with overheating? ( Poor driveability, sputtering, bogging, etc) If not, your truck isn't overheating.

I have a 49 3100 that had same issue overheating when setting in traffic. It has the 216 with an aluminum radiator. My problem was that it wasn't in time quite right. Messed with it all spring till I got the timing right. Now it doesn't over heat. Even was in a Halloween parade with no issues. Like someone else said check other things. Grady.

I use one of those aluminum flex fans that moves a ton of air (just to answer the question).

But yeah, a bone stock configuration didn't notoriously overheat back than, so it should work as well today (given your cooling system is in order).
In my experience it is not enough advance timing - especially at idle, that makes them go hot in traffic.
Most folks that set the timing by the (original) book, are at around 10-15 deg (depending on idle rpm) - I'm usually around 27, which makes quite a difference

Frank

Thanks all,

It is not boiling over or experiencing the problems you described, I’ll def check the timing. Maybe a secondary water temp gauge for a “second opinion” is in order. As always, thanks so much for the help.

GradyB, where did you finally set the timing?

Can't really say as I just did it by sound and taking it for drive. Then doing again if it didn't run right. I think the distributor is off a tooth from top dead center because timing with a light doesn't work.

Before you do that check out Segal's Law.. You may need at least 3 temp gauges.

Hi TKM,
If you change your mind and want to go the electric fan route, in my opinion there is no better fan than a Spal fan and the shroud sold by Antique Air (made for the AD truck) is hard to beat (although some claim to have made their own using commercial size cookie pans). I have one connected to an adjustable thermostat switch and this allows me to adjust any running temperature I want. I also have a 3 core aluminum radiator. In DFW we have summer pretty much 300 days a year (it is currently 84 degrees here and that is our "autumn") so driving in city traffic means you need mucho airflow. It has been a while since I was in Detroit. Main thing I recall is your summers were shorter but pretty humid. Good luck.

Maybe 4 gauges just to be sure 😆

JonG,

Thanks for the recommendation,I did a quick search for an AD designed electric fan setup a while back, and didn’t find any, which was a little surprising – so I will def check out your source if advancing the timing doesn’t fix the issue – it’s fall here now, so will have to wait for first hot day 6-7 months from now !

JonG,
I presume you used a pulling fan, not a pusher since you mentioned a shroud – there is little clearance between the water pump and radiator, did you have to “offset” the fan motor? Or did spal fan have a thin enough profile to fit between the water pump and radiator? Thanks so much for your help