Radiators 2 / 3 or 4 Core?

... ready to put in an Alum radiator with electric fan and shroud, read somewhere that 3/4 core radiators may not be as efficient as 2 core with 'bigger tubes' .

any comment or actual info appreciated

typical :

2 row

https://www.ebay.com/itm/1970-77-Fo...=item23b443dc23:g:JoYAAOSwx2dYF9Bm:rk:23:pf:0

3 row :

https://www.ebay.com/itm/3-ROW-CC33...=item4b56853567:g:H~kAAOSwX6Rb~6VN:rk:85:pf:0

4 row
https://www.ebay.com/itm/1970-1977-...=item1ef1dbb80b:g:q~4AAOSws2RcLTYs:rk:17:pf:0

have fun

 

I have a 2 row...no problems in the Ga. heat.

 

Nice radiator with a decent price but Speedcooling does not have a listing specifically for a Maverick. Is the one you used the one listed for the 67-70 Mustang? If so, does it need to be modified to fit? My car is a 302 automatic with a/c.

 

If you install a 3 or 4 row radiator, you'd better have a fan that can move a serious amount of air, or it will actually run hotter than a 2-row at idle and slow speeds. A cooling system is made up of components that must be designed to work together.

 

Go with a two core. I made the mistake of getting a champion 3 core a few years back because I got a great deal on it. I spent a lot more money and modifications to get it to work with my mild 302 than I would have if I had just gone with the 2 core. I will eventually replace it with a champion 2 core. Like larry said, you have to have a lot more air movement to cool it at idle than you would think.

 

There is so much confusion about cooling system performance and design and incorrect info keeps getting perpetuated. It is a SYSTEM of components. You have many factors involved with "what makes a good cooling system" and the radiator is purely the heat sink portion of the deal. Many are problematic because the fan itself is too far from the core and/or has no shroud but it has absolutely nothing to do with slightly reduced flow rates through the core itself. Now, granted a thicker rad can cause a reduction of efficiency when the system has other underlying issues but blaming increased core count alone is the absolute wrong way of looking at it when you consider how small many OEM rad's and the available grill opening sizes are today.

Unless it's really plugged up or the lower hose is collapsing.. a 3 or 4 core will NOT become the primary cause for overheating. Best radiator in the world won't work at peak efficiency if the waterpump moves smaller coolant volume, especially at idle with an old style lower blade count OEM fan. Underdrive pulleys will only compound the issue even further. When engines run warm too many people quickly assume the radiators with higher core count are stifling enough airflow to cause the issue. WRONG! The radiator choice only aggravated the underlying issues with poor coolant and airflow rates. Even with an old antique downflow rad design these issues can be fixed if you understand what's going on to prevent adding insult to injury when new parts are added to the system.

Clearance-wise kinda looks like you will be going e-fan with that engine anyways(can't tell in pic.. maybe already has e-fans?).. so I'd recommend a wider tubed 2 core with custom inner shroud and fans set up as pushers in the front. Follow that up with a lower temp t-stat(no more than 180 tops, 170 is perfect for summer, 160 for pure tuning lattitude) and some water wetter.

The lower temp t-stat(ESPECIALLY the 160) will be open further at idle speeds and therefore allow more water volume through whatever radiator you currently use. In your case it will also help improve octane tolerance and ward off detonation a little longer(more headroom until full heat saturation occurs during low airflow or full power output levels). Or.. if the tuneup already has plenty of safety margin built in?.. the lower base temps can allow you to get more aggressive with the tuneup without hitting the octane tolerance/detonation wall as quickly.

PS here's a good read regarding some of the physics involved with cooling systems.

https://www.flowkoolerwaterpumps.com/pages/why-flowkooler-hi-flow-pumps-end-overheating

 

Like I said, people make the mistake of increasing rows/core thickness without increasing airflow, which can cause overheating at idle and slow speeds. Don't believe me? Feel free to learn the hard way. All cooling system components must be designed to work together. It's true that the coolant flow must be sufficient, but if it was sufficient before the bigger radiator was installed, then upgrading only the radiator is the problem.

 

So let me make sure I'm understanding this correctly. Same exact rad design comparisons.. you're specifically saying that the slight reduction in airflow from a 2 to 3 core(have you ever looked at daylight exposure differences between various radiator core thickness?) is overshadowing the higher core counts improved coolant flow capabilities?

I and just about anybody who's ever hotrodded or just plain worked on many old cars will typically tell you unsuccessful larger radiator swaps generally only flushed out other underlying issues. Put a bigger rad in.. hmmm.. didn't do what I'd hoped?.. find the underlying issues before you blame a LARGER capacity radiator which has IMPROVED FLOW capability. On a properly built and maintained cooling system not once have I... EVER.... witnessed a larger higher flowing larger core count radiator swap cause issues or a reduction in cooling capability at idle.. WOT.. or anything in between. That just plain defy's the laws of physics and their order of importance to a cooling systems overall performance. There is VERY VERY little additional airflow resistance differences between lower and higher core count units when a fan is moving a couple hundred cfm of air at IDLE RPM. The bigger differences and ultimate flow losses occur at much MUCH higher air speeds. Such as racing along at 100+ mph.

Don't misunderstand my point. Have I seen a larger core rad swap cause issues when combined with a marginal fan having no shroud and 195 dgree t-stat? Well yeah.. but I certainly wouldn't call the larger volume higher flow radiator the CAUSE of the car not running as cool as intended.

In the end the math is simple to do. Per core available flow area x number of cores. Of course internal construction and sharp edges can impact the flow from high side to low. If you can't increase the number of cores being used then you should go larger on the cores that you have available. This generally makes for a lighter and more efficient flowing design over the baseline. I've successfully run and helped tune cars with small tiny little sirocco(speeling?) cores.. and the electric fans just run more often is all. Still cools a 600+ horse motor just fine at idle. My old 550 horsepower 429SCJ motor had a custom 4 core deal with proper shroud and factory fan. Cooled just fine as well even after switching to dual e-fans later on. And my last 563 horsepower 383 Chevy build used an old late model Camaro single 1.25" cored plastic tanked deal with 160 t-stat and water wetter. Had to be a longer sit time before the fans would finally come on around 185-190.

It's not magic.. can and has been done to death with the old school designs because at one time.. that's all we had to work with. The biggest major benefit to the newest designs is weight savings based on shrinking materials and use of composites. Newer designs can be smaller and still shed BTU's like an old antique 3 core. But pound for pound they are not worlds apart in BTU capability.

PS. by your theory of operation.. just about any car with AC condensers mounted out front would be overheating in non-efan applications during idle. Most cooling systems have far more headroom than some folks seem to imagine but they need to be operating as intended to maintain it. This is why today's cars can literally double their power output while still using STOCK cooling systems. Superchargers and turbo's don't make boost at idle and aside from the added radiant heat sources most engines of similar displacement are going to shed similar BTU's at idle speeds. Just need to be sure the air and water is moving as efficiently as that particular design will allow.

 

It's not my theory. It's what aftet market radiator manufacturers say, and I have petsonally seen the evidence of it on a friend's '65 Mustang. It's just plain physics. If you slow the airflow, the heat will increase.
Of course it's a no-brainer that coolent flow is just as important, and should be a REALLY no-brainer that the right thermostat is necessary. The stock Maverick with A/C has a 3-row radiator. The after market 2-row aluminum radiators have bigger tubes and cool like the stock 3-row(or even better). A 4 row with no other changes is asking for trouble.

 

Put an e-fan on it and all those "low speed airflow" concerns go away as soon as the relay kicks in. Go one step further and use an e-pump?.. and all the "low speed coolant flow" concerns disappear immediately as well. Then the issue becomes one of reliability and should be based on the type of driving and time/miles involved. Higher quality premium e-parts cost more but certainly help durability and lifespan.

Every single year I'm constantly amazed at how small a radiator can actually be used to cool high horse street car combo's. Last years summer nationals had a twin-turbo LS powered mustang idling in its show bay and people there were amazed and talking about how little the e-fans actually kicked on. 85'ish degrees out and they only kicked on twice for about 2 minutes each while I hung around patiently waiting to hear a few quick snaps of the throttle. Probably 4-5 minutes of idle time in between.

Newer tech just plain kills the old fan-n-shroud deals no matter what style or how big the radiator is. Air and coolant flow are FARRRR more important then worrying about getting the best radiator designs money can buy. And that's not just theory either.. just simple physics and personal first hand experiences gained over the last 35+ years keep me grounded in reality.

 

Yes. I was referring strictly to more rows with no other changes, which is also why I stated that all the components must be matched to work together.

 

OP also has a non-stock SC'd V6 engine which puts out less BTU's than a stock 302 so it's pretty damned hard to screw up this cars cooling capability at idle. More rows(which then adds capacity and higher flow capability) ALWAYS helps these old cars radiators BTU capacity(sure, efficiency goes down per core but capacity and BTU capability still increases). Unless there are other underlying issues mentioned above which made the system marginally able to handle the engines idle BTU's in the first place.

Remember a time when adding cores was all we could do to add greater cooling capacity? My uncles and I used to scout wrecking yards for HD radiators that either already had or would accept 4 cores(same end tanks as HD models but without the added cores) and then have the radiator shops re-core them to needed dimensions. Even made custom mounts at times to swap to larger tanked/cored designs. Worked perfectly for my factory cooled(fan and shroud) big-block Torino in SoCal's 100+ degree summers. Adding cores was a very popular mod in hotter parts of the country.

A decent enough 7 blade fan with properly sealed shroud, 180 t-stat and water wetter will run cooler with a 4 core over a 3 core over a 2 core. Obviously a 2 core won't pass twice as much air as a 4 core or vice-versa. There is well more than enough airflow even at idle speed on a properly designed system to pull air through an additional core. In fact, all OEM radiator designs(then and now) are built with some added headroom to compensate for poorly tuned and maintained engines/cooling systems/slipping belts being operated in higher ambient temps. Makes perfect sense considering they spent millions designing their cars well enough to help avoid overheating and warranty claims. When those things happen we troubleshoot for the cause of the underlying issue.. not the core sizing attributes alone.