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Discussion Starter · #1 ·
I've recently installed an Classic Auto Air into my 65 mustang coupe and immediately began to run hot about 215 degrees.

Replaced thermostat and housing
Added a Scott Drake 2 row aluminum radiator plus electric radiator fan and its running hotter than before (previously had 5 blade with housing) and despite it being loud and seems to be pulling a lot of air my temps keep going up.

All new fluids - running wetter water / distilled water / antifreeze mix and still getting temps around 230 degrees if going around town or sitting in traffic

Socal so shouldn't be too bad but I'd like to use the car as a daily driver.

Any suggestions or tips on what to try next would be appreciated

Thanks

799136
 

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I don’t see that you have a problem. The stock 195 degree thermostat, which you should be using, doesn’t even fully open until 210-212 degrees F.

Z

799162


PS at a stoplight the temp can go up to the 230 range without hurting anything as long it goes back down when you are moving.
 

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I would verify that your electric fan blade is installed for pulling air through radiator AND correct rotation of motor.

Some fan blade designs require flipping it if going from a pusher to puller fan.

Just in case.

I verified mine while installing my Classic Auto Air daily driver…and it’s been on the car almost 10 years…I verified it 10 years ago too.😁
 

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I think you may be overthinking this sbf like to be at 200 mine doesn’t even run right at 160 , I have a 3 row with a e fan 195 thermo and a new water pump and it can handle this 114 as heat up a mountain look into the acid cooling flush I got a lot of crud out with that
 

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I've recently installed an Classic Auto Air into my 65 mustang coupe and immediately began to run hot about 215 degrees.

Replaced thermostat and housing
Added a Scott Drake 2 row aluminum radiator plus electric radiator fan and its running hotter than before (previously had 5 blade with housing) and despite it being loud and seems to be pulling a lot of air my temps keep going up.

All new fluids - running wetter water / distilled water / antifreeze mix and still getting temps around 230 degrees if going around town or sitting in traffic

Socal so shouldn't be too bad but I'd like to use the car as a daily driver.

Any suggestions or tips on what to try next would be appreciated

Thanks

View attachment 799136
Thanks for your post. I am (and have been) dealing with the exact same issues on my 66 fastback. My configuration is as follows: 315 HP 289 w/ ProFlo EFI, Vintage Air with Sanden compressor, full Painless harness (like yours), Champion 3-row aluminum radiator, Vintage Air electric fan (2700 cfm) controlled by the EFI, Milodon 180 degree high flow thermostat, fresh 50:50 coolant w/ water wetter.

At ambient temperatures up to about 80 degrees, the whole system works great. The engine warms right up to 180, and then stays in the 180-185 range with only slight variation based on load; this is what I like to see - temperature control. However, as soon as you kick on the AC, the temperature shoots up to ~ 215 degrees; the AC compressor, evaporator and condenser present quite a large heat load to the cooling system. In hot weather, with ambient temps 85-100, the engine runs hotter without the AC (185-195); but with the AC on, the temperature goes to 220-230 degrees. As some say, those temps may be "normal" for the SBF, but I just don't like it.

The thermostat is supposed to function like a proportional controller - it opens more to cool more at high temperature / high load, and then closes some when the temp / load drops. If the coolant temperature runs up to 230 degrees (50 degrees above the "set" temp), that is no control at all. This, then, leads to the second issue - cooling capacity. Mustangs are renowned for their tiny little radiators that were designed for 200-225 HP, no air conditioning and less global warming, and there are threads all over VMF about Gen 1 Mustang overheating issues. The thermostat cannot control the higher temperatures / loads if there is not enough cooling capacity once the thermostat is fully open. Urban legend provides a little rule of thumb that says you need 1 square inch of radiator core face area per horsepower. The core area of my Champion radiator (and your Scott Drake radiator) have about 282 sq in of exposed face through the core support, which in my case is not quite sufficient for the engine horsepower. Note that even Ford recognized this issue and put larger radiators in Mustangs starting in 67.

My solution to this problem - in progress - is to experiment with a larger capacity radiator, but this is a real challenge in a Gen 1 Mustang. The original structure of this car is sacred to me, and I am not going to cut up the core support. I have found a side-tank, double-pass, cross-flow (rather than down-flow) aluminum radiator with a 3" deep core that fits reasonably well in the available space. The core face area is 315 sq in (matches the rule of thumb for my car), and the core support only impinges into the face area by ~ 3/8". I am hopeful that the additional flow, coolant capacity and face area will restore some degree of control so the thermostat can actually do its job.

Then, I can deal with the actual operating temperature issue. Although my car runs great at 180 degrees, many VMFers say that 180 degrees is just too cold for a 289, and the stock Ford thermostat was 195 degrees. Once I am able to achieve some degree of temperature control within the cooling system, I can then decide what temperature to run at by changing the thermostat, which will then control at the desired temperature.
 

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look into the acid cooling flush I got a lot of crud out with that
^^^^^^ this .

his radiator is new, but OP shouldn’t overlook flushing out the engine block as much as possible. Rust and scale adhering to the block hurts heat transfer and is a major contributor to cooling issues.

But as mentioned earlier, the temperatures indicated by the OP wouldn’t alarm me at all.

Z
 

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^^^^^^ this .

his radiator is new, but OP shouldn’t overlook flushing out the engine block as much as possible. Rust and scale adhering to the block hurts heat transfer and is a major contributor to cooling issues.

But as mentioned earlier, the temperatures indicated by the OP wouldn’t alarm me at all.

Z
I think I will do that as well.
 

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According to the R134A chart at 80°F, the high side is going to be close to 250 PSI. At 250 PSI the temperature of that gas is going to be ~140°F. That's ~140°F added to the load that the radiator has to deal with.

I see you also have vacuum advance. If you're not doing it already, run or try to make it run with full manifold vacuum at idle. The engine will normally run cooler with full manifold vacuum over ported vacuum. That's why the auto industry switched to ported in the early emissions years, to make the engine run hotter at idle to burn off the exhaust more completely.

Oh, nice job on the fuel line! Refreshing to see someone bend a nice fuel line instead of a couple feet of rubber hose.
 

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Discussion Starter · #10 ·
Thanks for your post. I am (and have been) dealing with the exact same issues on my 66 fastback. My configuration is as follows: 315 HP 289 w/ ProFlo EFI, Vintage Air with Sanden compressor, full Painless harness (like yours), Champion 3-row aluminum radiator, Vintage Air electric fan (2700 cfm) controlled by the EFI, Milodon 180 degree high flow thermostat, fresh 50:50 coolant w/ water wetter.

At ambient temperatures up to about 80 degrees, the whole system works great. The engine warms right up to 180, and then stays in the 180-185 range with only slight variation based on load; this is what I like to see - temperature control. However, as soon as you kick on the AC, the temperature shoots up to ~ 215 degrees; the AC compressor, evaporator and condenser present quite a large heat load to the cooling system. In hot weather, with ambient temps 85-100, the engine runs hotter without the AC (185-195); but with the AC on, the temperature goes to 220-230 degrees. As some say, those temps may be "normal" for the SBF, but I just don't like it.

The thermostat is supposed to function like a proportional controller - it opens more to cool more at high temperature / high load, and then closes some when the temp / load drops. If the coolant temperature runs up to 230 degrees (50 degrees above the "set" temp), that is no control at all. This, then, leads to the second issue - cooling capacity. Mustangs are renowned for their tiny little radiators that were designed for 200-225 HP, no air conditioning and less global warming, and there are threads all over VMF about Gen 1 Mustang overheating issues. The thermostat cannot control the higher temperatures / loads if there is not enough cooling capacity once the thermostat is fully open. Urban legend provides a little rule of thumb that says you need 1 square inch of radiator core face area per horsepower. The core area of my Champion radiator (and your Scott Drake radiator) have about 282 sq in of exposed face through the core support, which in my case is not quite sufficient for the engine horsepower. Note that even Ford recognized this issue and put larger radiators in Mustangs starting in 67.

My solution to this problem - in progress - is to experiment with a larger capacity radiator, but this is a real challenge in a Gen 1 Mustang. The original structure of this car is sacred to me, and I am not going to cut up the core support. I have found a side-tank, double-pass, cross-flow (rather than down-flow) aluminum radiator with a 3" deep core that fits reasonably well in the available space. The core face area is 315 sq in (matches the rule of thumb for my car), and the core support only impinges into the face area by ~ 3/8". I am hopeful that the additional flow, coolant capacity and face area will restore some degree of control so the thermostat can actually do its job.

Then, I can deal with the actual operating temperature issue. Although my car runs great at 180 degrees, many VMFers say that 180 degrees is just too cold for a 289, and the stock Ford thermostat was 195 degrees. Once I am able to achieve some degree of temperature control within the cooling system, I can then decide what temperature to run at by changing the thermostat, which will then control at the desired temperature.

Very much interested to hear if your bigger rad setup helps
 

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My 64 had a cheap aluminum radiator, 7 blade ford factory flex fan, repo steel fan shroud and AC. I had the car running and it would work it's way up to 230 degrees idling with the air on in 90+degree heat.

I replaced the 289 with a 5.0 based 331, switched to a repo brass radiator, kept the factory flex fan (because I was in a time crunch to get the car running and my C6oe-G fan clutch didn't fit), repo fan shroud and the AC. I did take the time while the motor was out to put weatherstripping on the fan shroud and actually get a good seal on it to the radiator. I've had the car idling in 90 degree heat with the AC on and was only at 214, so that's a good reduction in temps in my opinion. I'd prefer to not get above 200 or 210 max but unless I get the guts to cut my radiator support for a 67+ radiator this is as good as it gets.
 
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My 64 had a cheap aluminum radiator, 7 blade ford factory flex fan, repo steel fan shroud and AC. I had the car running and it would work it's way up to 230 degrees idling with the air on in 90+degree heat.

I replaced the 289 with a 5.0 based 331, switched to a repo brass radiator, kept the factory flex fan (because I was in a time crunch to get the car running and my C6oe-G fan clutch didn't fit), repo fan shroud and the AC. I did take the time while the motor was out to put weatherstripping on the fan shroud and actually get a good seal on it to the radiator. I've had the car idling in 90 degree heat with the AC on and was only at 214, so that's a good reduction in temps in my opinion. I'd prefer to not get above 200 or 210 max but unless I get the guts to cut my radiator support for a 67+ radiator this is as good as it gets.
I could certainly live with 210-214 degrees, if that is as hot as it would ever get sitting in a traffic jam on the turnpike for an hour in 100 degree weather with the AC blasting. But I'm not there now ...
 

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I have used the same aluminum 2 row 1” tubes radiator from Northern (Summit Racing) for over 10 years now.

With warmed over 289/C4/180 thermostat (carbed) and stock 5.0/T5/195 thermostat (EEC IV) with no problems with cooling.

Just made a trip to Texas and back with Classic Auto Air daily driver unit.
Used a/c with no problems.

Only overheating problem I had pertained to my dumb use of a vacuum cap to plug the foxbody EGR line on steel tube…a real heater hose, 1/4” bolt, hose clamps fixed my error to get us home.

BTW, have been using 16# radiator cap since the mid 90’s.
 

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KJE, 220~230 wouldn't scare me. Many folks get worried when they really don't have to. Yeah, a nice water pump, like the B2 cast impellor, might help you. It certainly can't hurt. And be certain you have full manifold vacuum on the distributor, as was mentioned. And consider at least TRYING a big 6 or 7 blade fixed fan, or the Cougar Shop's 7 blade clutch fan. Most of the electrics just AREN'T up to the job. And you may also consider an R model front splash pan, to let more air in. LSG
 

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Discussion Starter · #17 ·
KJE, 220~230 wouldn't scare me. Many folks get worried when they really don't have to. Yeah, a nice water pump, like the B2 cast impellor, might help you. It certainly can't hurt. And be certain you have full manifold vacuum on the distributor, as was mentioned. And consider at least TRYING a big 6 or 7 blade fixed fan, or the Cougar Shop's 7 blade clutch fan. Most of the electrics just AREN'T up to the job. And you may also consider an R model front splash pan, to let more air in. LSG
Thanks for the feedback

Can i ask a dumb question, where does the "full manifold vacuum" hook up? I've read online that it's a hex bolt close to the fire wall but struggled to find a good pic of someone running it on a V8

Thanks
 

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Ditch the electric fan and go back to the mechanical fan. Better if you go to a mechanical fan with thermal (not viscous) fan clutch and the A/C shroud. Next, increase your base timing to 12-14*BTDC if not already there and connect your vacuum advance to a full manifold vacuum port. If you are running an Autolite carburetor there will be a vacuum "tree" screwed into the intake manifold directly rearward of the carburetor (see image below). If you have an Edelbrock, Holley, Carter, Summit or other aftermarket carburetor, consult the manufacturers installation instruction for the location of a full manifold vacuum port or, again, use the "tree". If you now experience "kickback" on the starter retard the timing in 2* increments until it cranks normally. If you experience a "ping" at low rpm under load you may need a slightly heavier advance spring(s). If you experience a "surging" at very light cruise and moderate rpm you may need to adjust the vacuum advance diaphragm to reduce advance at high vacuum. If you experience a "ping" at high rpm and moderate load you may need to install a "limiter cap" on your mechanical advance.

Run as much spark advance as your engine will tolerate to lower combustion temperatures and cooling system heat loading. Also, since you probably already have a cooling fan sensor, you can try installing an idle "kicker" solenoid, controlled by your fan sensor, to energize the solenoid at, say, 215-220* to raise the idle speed by a couple hundred rpm to increase fan performance.
 

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Thanks for the feedback

Can i ask a dumb question, where does the "full manifold vacuum" hook up? I've read online that it's a hex bolt close to the fire wall but struggled to find a good pic of someone running it on a V8

Thanks
Your carb should have both ported and full manifold vacuum ports.
Rusty
 
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