Early Mustang Cooling Systems Part 2: How to Choose the Best Radiator, Fan Shroud, & Cooling Fan!

Early Mustang Cooling Systems Part 2: How to Choose the Best Radiator, Fan Shroud, & Cooling Fan!
In Part 2 of my cooling system videos, I'll discuss the flaws of original equipment and stock direct replacement style radiators, and then show you what to look for when selecting a replacement radiator like the S1MS-259-2AL-MT 1965-66 Shelby Aluminum Radiator from Scott Drake.
www.drakeautomotivegroup.com/...
I'll compare the inadequate factory style fan shroud to a high quality upgrade like the C3DZ-8146-3F '65-66 Mustang 3 1/2 inch Fiberglas Fan Shroud also from Scott Drake.
www.drakeautomotivegroup.com/...
And finally, I'll discuss the stock 4-blade 289 HiPo fan, the 6-blade air conditioning style fan that was on my Shelby, and the 17" Flex-A-Lite flex fan I'm going with to keep my car cool whenever I want to go for a drive.
www.flex-a-lite.com/belt-driv...
For Cooling System Review, Part 1 begins with an overview of cooling system operation, broken down to six areas, and turns to focusing on the function and correct application of the thermostat, with insight on how and why choosing the correct thermostat temperature rating is critical to cooling system operation.
Coming Soon:
Part 3: This video looks at the differences between various water pumps, including the different styles of water pumps used on small block Ford V8 engines through the years. Again, I’ll go in depth on the important design elements that will make or break your cooling system operation, and show you that a great water pump doesn’t have to cost a fortune.
This series of videos is something I’ve wanted to do for quite a while and now that I’m in the middle of rebuilding the cooling system for my 1966 Shelby GT350 Mustang, it’s the perfect opportunity for me to share my knowledge with you.
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Thanks for watching!
#shelby #ford #mustang #gt350 #shelbygt350 #mustanggt350 #shelbymustang #v8 #cooling #coolingsystem #overheating #radiator #fanshroud #flexfan #electricfan

[@Mountian-Zen]

It’s known that Aluminum with the right airflow dissipates heat at a much greater rate, cooling efficiency with Aluminum exceed that of any other, example all air cooled cylinder heads are Aluminum. Your insight on fan shrouds and the flex flan in particular are right on!!!!

[@roadscapehorror-talesofterror]

Great content and information! I have a 66 Hertz that is a day two car so I am on board with your approach. I greatly appreciate your knowledge on the mechanicals and so on. I never knew that the thermostat opened and closed during the operation of the car. I thought it just stayed open once the engine was up to temperature. Very interesting for me.

[@narish19]

I bought the same setup, lets see what it does. Thank you for sharing all your knowledge.

[@cplrecon]

Awesome! I just realized that my fastbacks do not have a fan shroud! I’m going to pick some up. Thank you for the awesome info! Keep it up!

[@TheGT350Garage]

A good shroud can improve airflow by 40-60% through the radiator core. Sealing the radiator to the radiator support and using a 6-cylinder radiator to hood seal can improve the airflow when driving as well.

[@rogsmith66]

Good information. Wish I found your wisdom in the 80’s

[@davidgabbay8682]

thanks for the tips!

[@president89]

This is a great video by the way.

[@TheGT350Garage]

Thanks for the feedback!

[@dcheetham8603]

Excellent - thank you!

[@saxonstangsetc3201]

Good information. 🤓

[@danemoll4065]

Very helpful 🎉

[@danemoll4065]

Just a quick note if it helps. I just replaced the original radiator in an original owners 1966 3 speed stick. I know that radiator was oem and original to the car. It too had the cooling holes for the auto trans. I believe that most of the radiators fitted at that time had holes regardless of use or not. Your video really helped me as I replaced with an aluminum aftermarket that required the 1-1/2 spacer as well. Thanks.

[@TheGT350Garage]

@danemoll4065 in 36 years of working on these cars, I’ve seen a lot of cars that were supposedly completely original but were far from. Even original owner cars are susceptible to having had parts changed and the owners not having records of the work being done or not remembering having the work done at all. It was incredibly rare for Ford to make the mistake of putting an automatic radiator in a manual transmission car. If you check the date codes on the tanks, you will likely find some discrepancies with the date codes of the rest of the car and drivetrain.

[@chipgarrett4135]

Love your insight on everything. Do you know a radiator like the one in your video that has the top plate to distribute the coolant across the whole radiator with inlet and outlet on the same side for a 68 mustang? Try to switch to a different water pump drop, and all I did was run into a belt alignment issue. Besides brackets that don’t alignment or have correct hole height,timing pointer covered up, witch makes you need a new timing pointer,seems the radiator that you mentioned would solve this nightmare! Spectacular information you give out,has made me subscribe and watch a lot of them, and found out that I don’t know crap about a lot of stuff that I thought I knew.

[@TheGT350Garage]

From Scott Drake (now a part of Holley) you can get the 20” or 24” radiators to fit ‘67-69 Mustangs with either lower inlet location. For passenger side 20” get 340-2AL or for the 24” get 338-2AL. For drivers side inlet you use the 67-69 big block or ‘70 type radiators, in 20” it’s 339-2AL and in 24” it’s 379-2AL. All of those are for automatic transmissions and have coolers in the lower tanks. If you have a manual transmission and power steering, you can use the cooler for the power steering instead of the transmission.

[@thomaseaton9421]

Hi Walter - love the videos. I have the same (non shelby) radiator and fan (plastic) setup and am wondering if you can provide more detail on what product you use to seal up the gaps, particularly on the sides where the radius extends beyond the rad. How do you go about addressing that? Thanks.

[@TheGT350Garage]

I made my own fan shroud mountings out of 16-gauge aluminum sheet and a set of modified 2-row fan shroud brackets that I riveted to together. I used threaded nut-serts to line up to the holes in the shroud and the shroud does require minimal trimming to fit the radiator best.

[@ford351cleveland]

Hi man awesome video really glad i found your channel. May i get your opinion on dubble or tri bypass radiators specifically on the pressure some people say that the waterpump creates, i tried to look it up on Eastwood website but with no luck.

[@TheGT350Garage]

The water pump creates flow, in the system, not pressure. The thermostat and heater bypass circuits flow enough coolant back into the pump inlet that the water pump typically does not need excessive torque to turn against any flow restrictions. I’ve had people ask me for high pressure water pumps over the years, there is no such thing. System pressure is purely heat driven, and is determined by the radiator cap. It’s all about the volume of flow with a water pump, not the pressure. With a radiator you don’t want unnecessary bypasses, you want the full flow of coolant to go to the radiator core when the thermostat opens to exchange warmer coolant from the engine with cooler coolant from the radiator.

[@BPattB]

The 65 I bought has the driver's side inlet (bottom) passenger side outlet (top). It cools very well. 160 thermostat and the car hasn't seen 180 in the year I've owned the car. That with 104 California traffic. The only problem with my style radiator is the alternator bracket. I welded a thick nut on the water pump because I only had 4 threads holding the spacer, and bracket to the pump. This bolt completely stripped out the threads on the old pump. Edit my r radiator had 40-plus rows, I'm running the stock style shroud and a newer style 5 blade fan.

[@mustangracer5124]

I put a 5.0 in my 65 fastback retrofitted to look just like a 289. I have a 3 row copper/brass rad. and a 17 " 'funky-fan' like you showed. no shroud.. Outside temps get to 120+ in my area and I likely will go with the shelby rad... the 3" shroud and the flex fan.

[@TheGT350Garage]

Pair that fan with the 3” shroud, make sure you seal it to the sides of the radiator core like I did mine, and use a 192° high flow thermostat. The final key to not overheating in high desert temps is the correct ignition timing. Needs to be 12-16° initial, a 16-20° curve that reaches peak timing at 2800-3000rpm, and a vacuum advance giving 12-15° at 14-16in/hg connected to manifold vacuum will have you maintaining temps under 220°F on the hottest days. One minor consideration is use a recovery style cap from an 85-93 Mustang and a coolant recovery bottle that holds 2-3quarts in conjunction with the ELC coolant I use and recommend in my coolant video.

[@fawzial-qatami7866]

Hi, great video ! I have a 1966 mustang 6 cylinder fitted with a 4 row radiator and a stock 4 blade fan. I have had a custom made shroud made from stainless steel. I want to fit an air conditioning system from old air. Do you think I can fir the air conditioning system with this set up? I do not have enough clearance for a bigger fan or flex fan. Thank you in advance

[@TheGT350Garage]

It is unlikely you have room for the air conditioning with your current setup. The condenser does go in front of the radiator restricting airflow and adding heat to the air passing through the radiator, so you’ll definitely need a better fan to move more air, but the longer inline 6-cylinder makes that very difficult. You may need to consider some modifications to the radiator support to allow a thinner 2-row cross flow aluminum radiator as a means to gain a couple inches of clearance. To do that you a remove the mounting point of the stock radiator by cutting the sheet metal, increasing the opening and allowing more area for air to pass through the core as well as adding space between the radiator and the engine. If you live in a place where air conditioning is highly desirable, that’s the best solution in your individual situation. The radiator support is available if future restoration deemed it necessary to install a stock type radiator again.

[@mrvango3648]

Thanks for the good information... Did you consider pulling on a "pusher" electric fan on the front of the radiator?

[@TheGT350Garage]

There’s no need for a pusher fan if the entire system is setup correctly. And at speed they are actually a restriction to airflow.

[@bernieblackford5594]

Great video and information… I have a Ford v8 pilot. Can I put an electric fan on the front of the radiator and have it push air through. Also could I then take the original fan off.

[@TheGT350Garage]

Pusher fans are problematic, they don’t work as well as puller fans.

[@billbarnett6848]

I have 64 falcon 289 with 3 row aluminum radiator electric fan ac car. Runs to hot in 90 to 100 degree weather at idle. Would the 259-AL radiator with the baffle on top of the tank make much difference?

[@TheGT350Garage]

Before you change the radiator, I would strongly suggest taking a look at the ignition timing. Initial advance should be 10-14° BTDC. The mechanical advance should produce 20° of advance by 3000rpm. The vacuum advance should be connected to manifold vacuum and add 10-14° of advance with full manifold vacuum. Incorrect ignition timing is one of the biggest contributors to overheating.

[@thomasbaker9780]

What rad, shroud n fan set up would be best for a 302 in a 65 mustang coupe?

[@TheGT350Garage]

A 302 has the same cooling needs as a 289, so one of the “259” style radiators, a 3” shroud, and a 17” 6-blade fan would be ideal. Again, that should be matched with a good water pump, and the engine should run a 195°F thermostat. Beyond that, the ignition timing and air fuel mixture from the carburetor are the final parts of getting the temperature where you want it consistently.

[@gandjhall1669]

Hi Walter, thanks so much for sharing your knowledge so generously. I am currently running a Spal 3000 CFM thermo fan on my 66 coupe and am about to fit a 195 degree Robert Shaw highflow thermostat to my car. Are you able to recommend the optimum temperature range fan switch that I should be using to control my thermo fan ? Thanks

[@TheGT350Garage]

If you are using an electric fan, I would strongly suggest an adjustable fan controller, not a switch. I like the basic electronic relay based Flex-A-Lite controller with the 1/4” probe, you can install the probe in place of the drain petcock location using a 1/4” NPT to 1/4” compression fitting, the compression fitting will seal the probe. It’s quite affordable and available from a ton of sources. flex-a-lite.com/compact-adjustable-electric-fan-controller-and-relay-kit-with-thread-in-probe.html Ideally, you want the fan to come on when the temperature rises at the bottom tank, that way the fan isn’t working unnecessarily and the fan should time nicely to thermostat operation. That controller also has provisions to be triggered by an A/C switch input and a manual override switch you could hide in the interior.

[@gandjhall1669]

@@TheGT350Garage Thanks a lot for the advice Walter. I'm assuming the drain petcock that you are referring to is the one in the bottom tank of my radiator. Am I correct in saying this ? Thanks

[@TheGT350Garage]

Yes. It makes draining the coolant a bit less convenient, but for as infrequently as we drain coolant, it’s a logical solution.

[@gandjhall1669]

@@TheGT350Garage Thanks for confirming. I really appreciate your advice. Thanks

[@paulleonard2211]

Will that shroud fit a 65 mustang 17 inch radiator?. Can you please send the shroud mounting hole spacing. I have a shroud I was told it will fit a 65 and it's 20 inches wide and the hole spacing is wider that the radiator flange

[@TheGT350Garage]

The shroud from Scott Drake is a little wider than the 65-66 radiators. The 259AL radiator is 17-1/2” wide and 16-3/4” tall, you have to trim the shroud slightly to get the best fit. The quick fix to make it work is get some 1-1/4” wide 1/8” aluminum and attach it to the factory style shroud brackets for your radiator core thickness (they make 2/3/4-row brackets, 2 being shortest. Then attach the shroud to the aluminum, mark it and trim it so it isn’t sticking out. The two flat pieces beside the core will seal the shroud to the face of radiator so the fan only draws air through the radiator core.

[@president89]

I just painted my aluminum radiator black with eastwood radiator paint. Verdict is still out. Car hasn't been driven yet.

[@fredturner2008]

Great video's. I just watch 1-5. I'm currently having a 331 stroker built for my 1966 Mustang GT with auto trans. Cooing is a big concern for the builder as well as myself. The engine is to be a "mild build " for a stroker. Just a Sunday cruiser. Builder has already mentioned the need for a good high volume water pump. In your opinion will the radiator, thermostat, flex fan and shroud you mention in video be a good fit? Probably end up about 350HP. Air Conditioning in the future if cooling system will handle it. Thanks!

[@TheGT350Garage]

Absolutely. The biggest thing you need to mention to your engine builder is do not under-cam the engine for the compression ratio. I would strongly suggest using a flat top piston over a dish, and use a larger combustion chamber to hold the compression down instead. Ideally you want 10.5:1 with aluminum heads, anything between 9.5:1 and 11.5:1 is easily manageable for temperature with the cooling system I’m running/suggesting. In fact, my 289 will be 12.2:1 on pump gas and close to 500hp. The other factor is the tune, I cover air fuel ratio and ignition timing in a couple other videos. If you’d like to discuss your setup in more detail please feel free to shoot me an email: [e-mail]

[@fredturner2008]

@@TheGT350Garage I'm looking at the Flex-a-lite 17" fans and not quite sure which one is in your video. Do you by chance have the part number for fan? My guess is #2017. Thanks.

[@TheGT350Garage]

2017, 1317, or 101567 will work. Some have different color hubs, some use different materials. Derale also makes a good 17” fan. The key is a wide stainless steel blade, and a riveted steel hub, also the center pilot hole should be 5/8” like the water pump.

[@BPattB]

What about a electric fan in front of the radiator and regular fan on the pulley system?

[@TheGT350Garage]

The issue with electric pusher fans is that they become a restriction to airflow at speed, when the temp is low enough the fan isn’t needed, it blocks airflow through the radiator. This means you need the fan more than you should, resulting in an unnecessary electrical draw as well. It’s better to use the 6-cylinder hood seal, close any gaps between the radiator and the core support, and limit the amount of air that can get around the radiator itself. Combined with those practices, using a good 3 to 3-1/2” deep fan shroud that the fan actually interfaces with, meaning half or more of the depth or the blade is in the shroud to turn fan wash into actual airflow through the radiator core. The final cooling enhancement I typically make is a simple 3” air dam the width of the frame rails below the radiator support, and yes, the strut rod mounts complicate the installation, but it creates a low pressure area in the engine compartment and increases the airflow through the radiator.

[@azteca8151]

Best radiator for an 67 inline 6 mustang ? Shroud , fan ? Thermostat for hot weather states..example California Miami etc

[@TheGT350Garage]

The best choice would be a 20” aluminum 2-row with 1” or larger tubes. Make sure you’re running a shroud, the 3” fiberglass or plastic ones are good, the original style metal shroud isn’t very effective. 17” 6-blade fan is a must. Thermostat needs to be a 195°F preferably, 180°F may work but the radiator needs the extra time to cool the fluid. Biggest issue with the 200 I-6 is getting the timing and fuel correct, which is difficult with a 1-barrel and a stock type distributor.

[@samfrawley8607]

Is the fan clockwise or counterclockwise? I have a 1966 automatic V8 mustang

[@TheGT350Garage]

Standard rotation is clockwise. The only time the pump and fan runs in reverse is with a serpentine accessory drive running the water pump and fan with the back side of the belt.

[@joshualymer6568]

Ford F-250 460 aluminum radiator 2 electric fans and shroud still cant keep cool at long idle I’m going back to a fan shroud and mechanical fan flex fan or steel fan with a severe duty clutch is a flex fan ok to use on a truck that I tow with

[@TheGT350Garage]

For towing you’ll want a large fixed blade fan with a heavy duty fan clutch. You’ll also want to catch my next video on the relationship between engine temperatures and engine tuning. Straightforward stuff that will help.

[@joshualymer6568]

@@TheGT350Garage yeah I sent you a message on IG about my cooling Drama 160 T Stat bad idea lol

[@joshualymer6568]

@@TheGT350Garage is that video out yet?

[@TheGT350Garage]

No, not yet. It will be up in a couple of days.

[@raptorjesus99]

I don’t think they make that Scott drake radiator. Are there other radiators with internal plate baffle? I saw you replied with Scott drake options. But I don’t think they have the internal plate. Is it a deal breaker?

[@TheGT350Garage]

That radiator came from Scott Drake with the Shelby part number. The exact same radiator is available without the Shelby logo/badge as a P/N 259-2AL-MT. www.holley.com/products/cooling/radiators_and_accessories/radiators/application_specific_2-row_radiators/parts/259-2AL-MT If you have an auto use a 259-2AL: www.holley.com/products/cooling/radiators_and_accessories/parts/259-2AL There is also a version for 5.0L/Driver Side water pump applications.

[@raptorjesus99]

@@TheGT350Garage sorry. Should’ve specified for a 67 mustang. There aren’t any for a 67 mustang and up with an internal baffle to distribute the water evenly

[@TheGT350Garage]

@@raptorjesus99 change the 259 to 340 in the link.

[@raptorjesus99]

@@TheGT350Garage yes but no internal baffle. Looks like it’s been discontinued for a 67-69

[@TheGT350Garage]

May be specific to the S7MS version but, not having the 67-up radiator in front of me I can’t tell you one way or the other. The 340-2AL would still be my first choice for a 67-up though, in an affordable option that offers hood cooling performance. If I was looking for ultimate cooling I would go with Griffin, Fluidyne, Ron Davis or C&R, and build a radiator to ‘67-70 Trans-Am specs for size and fitment. That’s not needed for a street car though.

[@EnemyOfReality584]

What are your thoughts on 2-row vs 3 or 4-row radiators?

[@TheGT350Garage]

You have to look at it this way; the stock Copper/Brass radiator was a 2-row, they were adequate for a stock car. If you add more load, like air conditioning , or make more power they aren’t adequate. A stock type 3-row is usually enough for 250-275hp w/ AC, or 300-325hp w/o. You have to be careful with 4-row radiators, you can reach a point where the core becomes an airflow restriction due to the thickness. If you feel like you need a 4-row, you should be looking at aluminum radiators at that point, 2 rows of 1-1/4” tubes is equal in coolant volume to a 4-row but they are slightly less airflow restriction than a 3-row copper/brass core. With radiators it’s as much about airflow through the core as it is about the volume of coolant. It takes optimization of both of those to be effective.

[@EnemyOfReality584]

@@TheGT350Garage thanks! I had a 3-core aluminum in my car but while at a red light, the temp would jump up from about 185-190 to over 215 (without the a/c on) if I sat long enough. Decided to go with a 2-core aluminum instead which seemed to help a little. After watching your thermostat video I think I'll try a 195 now and see if that helps any as well.

[@TheGT350Garage]

There are a couple more videos coming, and to really make the most of everything, you will need to make some changes to your distributor. I’m going to walk everyone through how to curve the distributor and set it up to make great power and help the engine run cooler.

[@EnemyOfReality584]

@@TheGT350Garage can't wait! I do have an Edelbrock ProFlo4 setup so not sure how much I can do there.

[@TheGT350Garage]

@@EnemyOfReality584 if it has any tuning software, With it you should be able to open the current map and make a couple of small adjustments, message me directly here, on FB or IG and I can work with you to figure it the best path to get it where it needs to be.

[@martinmetz8985]

Man you want me to get that radiator for my car. What’s the best way to flush my block..

[@TheGT350Garage]

First, find a local place to properly dispose of (recycle) your old coolant. Most counties in most states have set some system in place for this. With the old coolant completely drained, you can use any commercial cooling system flush, but be aware of the disposal requirements for the fluid you’ll be removing. I use about 1/2 cup per gallon of distilled white vinegar (so about 1 cup on an early Mustang), it’s completely environmentally safe if you spill it. It removes deposits in the cooling system because it’s a mild acid. Run the engine with the vinegar and hot water for about 20-30 minutes. Let it cool. Add 1/4 cup of baking soda and repeat, this neutralizes the vinegar and leaves you with dirty water with some mineral deposits that is safe to pour into a household drain. That radiator is a nice choice, you can get it from other sources without the Shelby stencil and badge by searching 259AL Radiator. It’s available with or without a transmission cooler in the lower tank.

[@martinmetz8985]

What’s ur thoughts on adding a 24 in rad by cuting the rad support

[@martinmetz8985]

Also what’s and when the next vid coming out

[@TheGT350Garage]

Completely unnecessary. The available drop-in/bolt-in radiators for these cars at every good now. Cutting the radiator support should be reserved for extreme cases where you need more clearance to the water pump or you’re trying to cool down a far more powerful setup than the current core size can cool. In that respect, you’re talking about 600+ horsepower.

[@TheGT350Garage]

Next video is almost complete. It’s a little different than the previous two, very specific to small block Ford timing cover and water pumps.

[@mrvango3648]

Typo... putting on a pusher.