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1967 Ford Mustang 2dr Coupe 289 4bbl
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My stock 289 (only change is a 4v Edelbrock carb) has had constant overheating issues this summer. I'm in Alabama so summer days regularly run 90-100*, and the worst is yet to come. My issue comes when I am sitting at idle after driving for pretty much any period of time beyond 10 minutes. Going through a drive-thru always has me sweating watching the gauge, and sitting in traffic is the same way. Usually, it takes about 5-8 minutes of idling for the car to raise from 190-200 (operating temp) to 220-225. Temperatures are checked using an IR temp gun on several points on the thermostat housing. I know for sure it is not a blown head gasket, coolant is very clean and the car cools easily once I'm over 30 mph. Also, the engine temp goes way up after shutting off, which I know is fairly normal, but any ideas on how to combat that would be appreciated. This is my daily so I need to be able to drive somewhere, park and shut off for 15 minutes or so, and crank it up and not have to sit and wait for temp to go down. Also, I have AC, so I do have an old condenser in front of the rad. Here is what all I have done to address this issue.

1. New 180* thermostat. (I know this does not dictate cooling on the engine, but it is new and not stuck or only partially open)
2. New 2 row aluminum Champion radiator, stock size (21"x22")
3. New 16lb rad cap
4. 75% distilled water, 25% green antifreeze. 1 bottle of water wetter
5. 6 blade direct drive fan, with a fan shroud
6. Engine has been flushed 3 times with Prestone
7. Water pump is not new, but does push a good deal of water at idle.

So what could the issue be?

I've read some things about the ignition (I think...) timing being off. I do not get any spark knock, so I don't know if that rules anything out. If it may be the ignition timing, how would I go about adjusting that? Does it need to be higher or lower to combat the overheating?

Do I need to just add an electric fan? If so, any recommendations on that (puller/pusher, where to put it- in between rad and condenser, or on the front of the condenser, brand, cfm, etc..?) Maybe a fan that kicks on at a certain temp and can stay on for a few minutes after the car is shut off? I currently have an alternator with 3 wires coming out the back, not sure what amps it is rated to. Also, I do not mind if the electric fan is noisy.

Any other ideas? I know I have a lot of words typed up there, but I am trying to be as helpful as possible and add as much background info as possible.

Thanks
 

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The best way to get a standing still temperature in the 220’s to go down is to start driving. Temperature in the 220’s while stopped in traffic or a stop light is not overheating.

Z
 

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16 pound radiator cap is good to 251F.
What makes you think it's overheating? Just that the temp is high? Are you boiling? Are you losing any water?
I put in a 3 row radiator just for good measure when my 2 row bit the dust.
 
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a. Connect your vacuum advance hose to manifold vacuum vs. ported vacuum.
b. Run as much spark advance as your engine will tolerate without 'pinging'.
c. Consider using a thermostat housing with a sender bung and installing a DVCV (distributor vacuum control valve) to operate as a hot idle compensator. (See picture below). At coolant temperatures above 220*F it will open a small controlled vacuum leak that will increase idle speed.
d. Consider using a throttle "kicker" solenoid triggered by your A/C compressor clutch to increase idle speed.

799272
 

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1966 289 2V Coupe FMX Transmission 9-inch Axle
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Off the top of my head, fan size as opposed to shroud size. 17" fan in an 18" shroud is good. Fan position in shroud and how close to radiator. 1" from radiator, fan half way in shroud. 5 ~ 6 blade with therm coupling clutch. Set your timing up.

Good info at this thread.
 

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1966 289 2V Coupe FMX Transmission 9-inch Axle
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a. Connect your vacuum advance hose to manifold vacuum vs. ported vacuum.
b. Run as much spark advance as your engine will tolerate without 'pinging'.
c. Consider using a thermostat housing with a sender bung and installing a DVCV (distributor vacuum control valve) to operate as a hot idle compensator. (See picture below). At coolant temperatures above 220*F it will open a small controlled vacuum leak that will increase idle speed.
d. Consider using a throttle "kicker" solenoid triggered by your A/C compressor clutch to increase idle speed.

View attachment 799272
I added a throttle "kicker" to my setup and it makes a big difference. I did change the gas pedal return spring to something a little lighter to help the solenoid out.
 

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1966 289 2V Coupe FMX Transmission 9-inch Axle
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My stock 289 (only change is a 4v Edelbrock carb) has had constant overheating issues this summer. I'm in Alabama so summer days regularly run 90-100*, and the worst is yet to come. My issue comes when I am sitting at idle after driving for pretty much any period of time beyond 10 minutes. Going through a drive-thru always has me sweating watching the gauge, and sitting in traffic is the same way. Usually, it takes about 5-8 minutes of idling for the car to raise from 190-200 (operating temp) to 220-225. Temperatures are checked using an IR temp gun on several points on the thermostat housing. I know for sure it is not a blown head gasket, coolant is very clean and the car cools easily once I'm over 30 mph. Also, the engine temp goes way up after shutting off, which I know is fairly normal, but any ideas on how to combat that would be appreciated. This is my daily so I need to be able to drive somewhere, park and shut off for 15 minutes or so, and crank it up and not have to sit and wait for temp to go down. Also, I have AC, so I do have an old condenser in front of the rad. Here is what all I have done to address this issue.

1. New 180* thermostat. (I know this does not dictate cooling on the engine, but it is new and not stuck or only partially open)
2. New 2 row aluminum Champion radiator, stock size (21"x22")
3. New 16lb rad cap
4. 75% distilled water, 25% green antifreeze. 1 bottle of water wetter
5. 6 blade direct drive fan, with a fan shroud
6. Engine has been flushed 3 times with Prestone
7. Water pump is not new, but does push a good deal of water at idle.

So what could the issue be?

I've read some things about the ignition (I think...) timing being off. I do not get any spark knock, so I don't know if that rules anything out. If it may be the ignition timing, how would I go about adjusting that? Does it need to be higher or lower to combat the overheating?

Do I need to just add an electric fan? If so, any recommendations on that (puller/pusher, where to put it- in between rad and condenser, or on the front of the condenser, brand, cfm, etc..?) Maybe a fan that kicks on at a certain temp and can stay on for a few minutes after the car is shut off? I currently have an alternator with 3 wires coming out the back, not sure what amps it is rated to. Also, I do not mind if the electric fan is noisy.

Any other ideas? I know I have a lot of words typed up there, but I am trying to be as helpful as possible and add as much background info as possible.

Thanks
Mine would do this after adding the A/C. Remember, the condenser with the A/C on is generating a lot of heat and then you are pulling this heated air through your radiator to cool the engine. So you have to move a lot of air at idle. Car moving down the road increases the air flow. If you have stuffed foam or other around all openings hoping to increase the air flow remove all that stuff. You want as much air from behind and the sides of the condenser which would be cooler air to pull through the radiator. I would use a mechanical thermal clutch fan, not an electric. 17" fan 18" shroud. Position fan 1/2 in/out of shroud. I live in the south so A/C is a must for me. It doesn't take much to cool this small car down.
Plenty of information on this forum.
 

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I’ve noticed lots of folks on this site don’t like electric fans, not sure why. I’m a huge fan rimshot! of them.

I’m also in Alabama (Huntsville, where are you?) and it gets pretty toasty. When idling, and it’s super hot outside, is when you want to have your A/C on, and it’s also when your condenser and radiator desperately need as much airflow as possible. With a mechanical fan, idling is when you get the LEAST amount of airflow.

The beauty of an electric fan (or dual fans) is you get fabulous airflow all the time, especially idling when you need it most. Since you’re running an aluminum radiator you’re already not stock, so I don’t think an electric fan is that big of a deal.

You do want to check your ignition timing. If the timing is retarded, the engine will run hotter. You also miss out on power unnecessarily. Advanced as much as possible without knocking.
 

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67 Mustang 351w
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Make sure the thermostat is installed in the correct direction. When I bought my car, they informed me it had an issue with overheating, and I found the thermostat installed backwards. Problem solved.
 

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I like this fan - it’s very quiet for an electric and moves a ton of air. You’d mount it inside, behind the radiator as a pulling fan. I have mine on a switch, I can turn it off if I want, but I just let it cut on when I turn on the key.

 

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I'm questioning the temp range you want. 190-200 is not a ideal operating temperature it is a bit too cold. On the same subject 220 is not overheating, particularly at idle on a hot day without air conditioning.

Please correct me if I am off on this but I always thought ideal temp was 205-215. You need the heat to boil out any water vapors from the oil (these occur naturally, particularly in humid places like AL), and I think it aids combustion too.
 

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I have nothing against electric fans, but I have no desire to install one on my Mustang. I don't want to mess with extra wiring, extra fuses and an extra draw on the alternator. I also don't trust them. My brother came very close to melting down the 383 in his classic Nova because the electric fan relay failed. He went to buy a new relay and learned most of them are complete junk and failures are very common. He rigged up a manual switch which is what a lot of people do.

I can relate to cooling issues. I'm in the process of installing a 24", 3-core radiator and 7-blade clutch fan in my Mustang. I had the same issue. It would slowly get hotter at idle. Revving the engine made no difference. The previous radiator was a 20" 4-core and I think the fan just couldn't pull in enough air across all 4 cores. Once the car was moving, the engine would run cool.

While the OP's engine may not be overheating yet, it sounds like it's on the ragged edge of doing so. If I was in the OP's situation, I would ditch the 2-core Champion radiator and install a factory style 3-core radiator with a 7-blade clutch fan. I think you can put a 24" radiator in a '67 Mustang. If so, I would do that. Check out the radiator video on the West Coast Classic Cougar web page; very informative. I got all my parts from there. They were very helpful with helping me to select all the exact parts I needed and they were on my porch a few days after I ordered.

What made me decide to go with the 24" radiator is I recalled I never had overheating problems with my '69 Cougar. That car was my daily driver for 12 years and I often got stuck in bumper-to-bumper traffic on the Hampton Road Bridge-Tunnel during sweltering southern Virginia summers. The Cougar came with a 351W and A/C from the factory and therefore had a 24" radiator and clutch fan. I have also talked to other VMF members who installed the same cooling system and they said it resolved overheating issues.

Good luck and have fun.
 

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When my 67' with a 289 was my daily, I was usually concerned when temps got in the 90's or higher (South east VA), so when the time came to replace the radiator I went with a 4-row and the stock 4-blade fan (admittedly I still need a shroud.) It did fine with that, a stock replacement water pump and a 180 degree thermostat only getting to 220-230 on occasion in stop-and-go traffic. I eventually added a 16" electric fan as a pusher to a switch inside the car, (you know because electric fans are the coolest!) With the pusher on, in traffic, at 90+ I don't remember it getting above 190.
 

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I have nothing against electric fans, but I have no desire to install one on my Mustang. I don't want to mess with extra wiring, extra fuses and an extra draw on the alternator. I also don't trust them. My brother came very close to melting down the 383 in his classic Nova because the electric fan relay failed. He went to buy a new relay and learned most of them are complete junk and failures are very common. He rigged up a manual switch which is what a lot of people do.
Lol so you do, in fact, have something(s) against electric fans.

Because the OP's cooling system works fine as long as he's getting decent airflow, I don't think he needs a different radiator. Heat is getting from the engine to the coolant (clean engine) and from the coolant to the radiator (good water pump and thermostat) it's just not getting from the radiator to the atmosphere (not enough airflow). A larger radiator and more coolant gives a little more surface area to get heat from the radiator to the atmosphere, but a 3 core is also a little harder to pull air through. Not saying a 24" 3 core would hurt per se, just that it might not be the fix.

If the OP doesn't want an electric fan, which is totally fine and understandable, then having a really good mechanical fan and shroud is a must. Along with having good placement of the fan and a shroud that fits well both to the radiator and the fan. If OP wants to go mechanical then that 7 blade fan from WCCC along with a shroud would be the way to go.

Also think it's worth double checking the timing and the fuel mixture, running retarded and/or lean will produce excess heat.
 

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I concur with what’s been posted. Plus:
1. Connect distributor’s vacuum advance to manifold vacuum (if it’s connected to port vacuum); or add a DVCV (distributor vacuum control valve) so that the distributor sees manifold vacuum above a set temperature. I do like @Woodchuck 's use of a DVCV as a vacuum leak to increase RPM.
2. Advance the timing if the engine will tolerate it.
3. If necessary, upgrade to a 24” 2-row radiator and shroud plus fan clutch.
 
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Lol so you do, in fact, have something(s) against electric fans.

Because the OP's cooling system works fine as long as he's getting decent airflow, I don't think he needs a different radiator. Heat is getting from the engine to the coolant (clean engine) and from the coolant to the radiator (good water pump and thermostat) it's just not getting from the radiator to the atmosphere (not enough airflow). A larger radiator and more coolant gives a little more surface area to get heat from the radiator to the atmosphere, but a 3 core is also a little harder to pull air through. Not saying a 24" 3 core would hurt per se, just that it might not be the fix.

If the OP doesn't want an electric fan, which is totally fine and understandable, then having a really good mechanical fan and shroud is a must. Along with having good placement of the fan and a shroud that fits well both to the radiator and the fan. If OP wants to go mechanical then that 7 blade fan from WCCC along with a shroud would be the way to go.

Also think it's worth double checking the timing and the fuel mixture, running retarded and/or lean will produce excess heat.
Point taken. Specifically, I have no problem with factory electric fans. :)
 

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I'm questioning the temp range you want. 190-200 is not a ideal operating temperature it is a bit too cold. On the same subject 220 is not overheating, particularly at idle on a hot day without air conditioning.

Please correct me if I am off on this but I always thought ideal temp was 205-215. You need the heat to boil out any water vapors from the oil (these occur naturally, particularly in humid places like AL), and I think it aids combustion too.
I'd love to hear a definitive, scientific answer on this. Cause when I watch Engine Masters and those guys are shooting for the most HP, they run engines at like 165*F. Conversely, I've always heard that the hotter the engine can safely run without overheating, the more efficient it is.
 

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I'd love to hear a definitive, scientific answer on this. Cause when I watch Engine Masters and those guys are shooting for the most HP, they run engines at like 165*F. Conversely, I've always heard that the hotter the engine can safely run without overheating, the more efficient it is.
Engine Master's isn't concerned with longevity, so having a temperature too low to evaporate water, etc. out of the oil is not an issue for them.

The maximum safe temperature is very dependent on the engine design, combustion chamber shape, fuel delivery system (i.e., direct injection, port injection, carb), timing, etc. etc., that there is no "definitive" answer. Having said that, those that know on this forum correctly note that Ford installed a 195º thermostat in these engines and they did not fully open until 210º or higher. I'm not sure what temperature the DVCV opens, but I think it is higher than 210.
 
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I'd love to hear a definitive, scientific answer on this. Cause when I watch Engine Masters and those guys are shooting for the most HP, they run engines at like 165*F. Conversely, I've always heard that the hotter the engine can safely run without overheating, the more efficient it is.
165 F ????

the engine master guys don’t have to deal with an engine full of sludge from the condensation in the oil never evaporating. Which is what happens in the real world when the oil temp is kept too low from over cooling.

why not trust the engineers that designed your vintage Mustang and also wrote the shop manual instead of some TV hack ???

The Ford engineers wanted the engine to run over 200 degrees F all the time . That’s why they selected a 195 F thermostat. A thermostat that doesn’t even fully open until 210-212 F.

the stock 195 thermostat was fitted to millions and millions of cars leaving the Ford plant. They ran fine. Our family’s Fords never were sidelined by overheating. The farther one strays from the factory setup the more issues will crop up.

Engine Masters may be entertaining, but it’s not informative.

They spew more disinformation than the Russians, Russian government that is. I’ve got nothing but sympathy for the Russian people trapped in their BS system.

52AC0E5D-A555-4A5C-B37A-85D83BA95E1C.jpeg
 

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I’ve noticed lots of folks on this site don’t like electric fans, not sure why. I’m a huge fan rimshot! of them.

I’m also in Alabama (Huntsville, where are you?) and it gets pretty toasty. When idling, and it’s super hot outside, is when you want to have your A/C on, and it’s also when your condenser and radiator desperately need as much airflow as possible. With a mechanical fan, idling is when you get the LEAST amount of airflow.

The beauty of an electric fan (or dual fans) is you get fabulous airflow all the time, especially idling when you need it most. Since you’re running an aluminum radiator you’re already not stock, so I don’t think an electric fan is that big of a deal.

You do want to check your ignition timing. If the timing is retarded, the engine will run hotter. You also miss out on power unnecessarily. Advanced as much as possible without knocking.
Living here in phoenix electric fans aren't well liked in the mustang commmunity. Having had 1 car with and 1 car without (both with A/C), I can definitely say I prefer my current non electric set up. It stays much cooler with less fluctuation. My car with an electric fan was very noisy, always got hot on the freeway, and required a beefed up charging system to run. I've been told by more than one person electric fans actually impead airflow when driving at higher speeds, which would explain why mine always got hot on the freeway.
 
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