Fan clutch or not

clocker · 05-09-2001, 04:49 PM

66 - 289 automatic with factory air. I need some input to as to keeping the fan clutch or not. Several people have given me different stories. I have one on it now but it run warm on a long haul (100 miles and over). It is fine when i am starting a trip and stays around the T on the gauge. Then after about a hundred miles it stars slowly warming up and gets up close to the P on the gauge. i was told that it is normal for that and also to change over and eliminate the clutch so the revs would draw more air. Anyone have any experience with this. Already have a 6 blade fan. Thanks
Jim

Dark Knight · 05-09-2001, 06:14 PM

doubt a fan is gonna pull more air thru at 100mph.. you might look into am external tranny cooler..it will help the radiator work better by not having to cool the tranny too..
the 65-66 stangs have tiny radiators..

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives stock shorties
stock cam, 1.7's
14.06@100.21, 255RWHP on a hot day
265 on the mph/weight chart

[This message has been edited by Dark Knight (edited 05-09-2001).]

zach0 · 05-09-2001, 07:38 PM

I have a 66' 289 with medium modified engine and bolted the fan straight to thewater pump with a spacer behind the fan of course and it runs cool all the time even with more water than coolant in system. It has roughly 75%W - 25%C and I dont have any problems around the city.

------------------
66 Mustang Black W/ Black
289 Hi-Po 65'heads, MSD
Lunati High lift Cam
750CFM Carb

clocker · 05-10-2001, 12:05 AM

Quote:

Originally posted by Dark Knight:
doubt a fan is gonna pull more air thru at 100mph.. you might look into am external tranny cooler..it will help the radiator work better by not having to cool the tranny too..
the 65-66 stangs have tiny radiators..

thanks -- i agree with you but i was a little vague - i meant on a trip of over 100 miles -not 100mph - i have only had it up to about 90mph so far but it was still climbing and i backed out of it - it is a stock engine and i am not sure how much faster it would take - it shows 138000 but was supposed to have been rebuilt around 90000 - jim

clocker · 05-10-2001, 12:10 AM

Quote:

Originally posted by zach0:
I have a 66' 289 with medium modified engine and bolted the fan straight to thewater pump with a spacer behind the fan of course and it runs cool all the time even with more water than coolant in system. It has roughly 75%W - 25%C and I dont have any problems around the city.

thanks - i dont seem to have any problem either around town - i run about 50-50 water/antifreeze and it is fine -- only after a long ride does it begin to warm up - jim

induction · 05-10-2001, 02:17 AM

On my '65 I use a product called:"water wetter" found at a local auto parts store.Yes i did see a differance in cooling ( about 10-15 deg. )I also use a 60 h20/40 mix in the stock radiator with no problem. I understand that these cars tend to run better at about 180-195 so dont put in a thermostat any lower than these.Also , I use the stock "4" blade fan.(289 -2bbl)

------------------
Restored 1965 Coupe
April Mare of the Month

Jaydee · 05-10-2001, 07:47 AM

What size radiator are you running? What temp thermostat?. My car always tended to run on the warm side (around 200 degrees while cruising and up to 215 degrees in traffic) Though all of the cooling system parts were visually ok,(but old),last summer I bit the bullet and replaced the water pump, put in a new 3 core radiator, a 50/50 coolant mix with the water wetter added in (it does work) and a new 160 degree thermostat (the car is summer driven only). After these changes the car runs @ 180 degrees consistiantly while cruising and has never topped 195 degrees in traffic, running the original 4 blade fan and a shroud. Also if your using the original factory temp gauge, you may want to consider adding a good after market gauge just to be sure that the reading is accurate.

------------------
1965 K code coupe - numbers matching - restoration ongoing. 1987 LX notch, 5 spd, stock heads (minor porting) and intake, 65mmTB, 3.55's, ram air, pulleys, shorty's, 2.5" exhaust with cats 13.89@100.25

thunderbolt · 05-10-2001, 10:06 AM

I have heard alot of stories over the years of rebuilt 289's running hot in older mustangs. Don't know why, my stock one ran around the T on the temp guage all the time. Anyway, I would get a total cooling system overhaul beginning with the radiatior. Have it cleaned out, rodded out if need be. Change your thermostat to a new one and get a new radiator cap. If the radiator is bad, replace it with at least a 3 row unit. Aluminum is expensive but has much better heat radiating qualities, and is lighter. If you replace the water pump, go with an aluminum unit. If you are still warm, think about the water wetter. If your cooling system is up the snuff, you may have an engine problem, probably insufficient cleaning at the rebuild. This last problem is probably not it but keep it in mind if all else seems to fail.

Dark Knight · 05-10-2001, 12:21 PM

you are running the fan shroud? that makes a difference at highway speed..
as for a rebuild... if it's .040 over, it's gonna run hot... might look into getting the radiator checked too..

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives stock shorties
stock cam, 1.7's
14.06@100.21, 255RWHP on a hot day
265 on the mph/weight chart

mustangII460 · 05-10-2001, 09:52 PM

Food for thought.

Factory pumps are designed for maximum flow around 2500 RPM's.

I Drag race my Stang and cut blades from the impeller, getting the cool I need. At a higher RPM a stock pump cavitates the water reducing flow. Lost yet?

A clutch fan is working about the same as its counter part at 2500 RPM's. So at the high revs the fan really becomes less a part of cooling as your pump spins the same with either fan.

At highway speeds where are your RPM's at? Above 2500? If so,I would go with a performance pump that moves a higher volume at higher revs.

Water wetter does work.

I would stay with the clutch and look into the pump. A larger radiator is always good.

My head hurts now.

67 shadetree mechanic · 05-12-2001, 02:27 PM

Is the radiator new or does it need replacing?
Is anything restricting air infront of the radiator?
Is the fan shroud missing?
Is the thermosat working properly?
Is any of the water hoses restricting water flow?
Are you losing any water?

Just a few experiences I've had in the past... My guess is the fan/clutch are not the problem but of course I haven't seen or know anything about your car.

Good luck.

05-09-2001, 04:49 PM	#1
clocker Registered Member Join Date: Sep 2000 Location: Port St. Lucie Fl 34952 Posts: 6	Fan clutch or not 66 - 289 automatic with factory air. I need some input to as to keeping the fan clutch or not. Several people have given me different stories. I have one on it now but it run warm on a long haul (100 miles and over). It is fine when i am starting a trip and stays around the T on the gauge. Then after about a hundred miles it stars slowly warming up and gets up close to the P on the gauge. i was told that it is normal for that and also to change over and eliminate the clutch so the revs would draw more air. Anyone have any experience with this. Already have a 6 blade fan. Thanks Jim

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05-09-2001, 06:14 PM	#2
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	doubt a fan is gonna pull more air thru at 100mph.. you might look into am external tranny cooler..it will help the radiator work better by not having to cool the tranny too.. the 65-66 stangs have tiny radiators.. ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives stock shorties stock cam, 1.7's 14.06@100.21, 255RWHP on a hot day 265 on the mph/weight chart [This message has been edited by Dark Knight (edited 05-09-2001).]

05-09-2001, 07:38 PM	#3
zach0 Registered Member Join Date: Apr 2001 Location: Hampton, Virginia Posts: 227	I have a 66' 289 with medium modified engine and bolted the fan straight to thewater pump with a spacer behind the fan of course and it runs cool all the time even with more water than coolant in system. It has roughly 75%W - 25%C and I dont have any problems around the city. ------------------ 66 Mustang Black W/ Black 289 Hi-Po 65'heads, MSD Lunati High lift Cam 750CFM Carb

05-10-2001, 02:17 AM	#6
induction The Brit! Join Date: Feb 2001 Location: Across the Pond! Posts: 694	On my '65 I use a product called:"water wetter" found at a local auto parts store.Yes i did see a differance in cooling ( about 10-15 deg. )I also use a 60 h20/40 mix in the stock radiator with no problem. I understand that these cars tend to run better at about 180-195 so dont put in a thermostat any lower than these.Also , I use the stock "4" blade fan.(289 -2bbl) ------------------ *Restored 1965 Coupe* *April Mare of the Month*

05-10-2001, 07:47 AM	#7
Jaydee Registered Member Join Date: Sep 2000 Location: Conn. Posts: 220	What size radiator are you running? What temp thermostat?. My car always tended to run on the warm side (around 200 degrees while cruising and up to 215 degrees in traffic) Though all of the cooling system parts were visually ok,(but old),last summer I bit the bullet and replaced the water pump, put in a new 3 core radiator, a 50/50 coolant mix with the water wetter added in (it does work) and a new 160 degree thermostat (the car is summer driven only). After these changes the car runs @ 180 degrees consistiantly while cruising and has never topped 195 degrees in traffic, running the original 4 blade fan and a shroud. Also if your using the original factory temp gauge, you may want to consider adding a good after market gauge just to be sure that the reading is accurate. ------------------ 1965 K code coupe - numbers matching - restoration ongoing. 1987 LX notch, 5 spd, stock heads (minor porting) and intake, 65mmTB, 3.55's, ram air, pulleys, shorty's, 2.5" exhaust with cats 13.89@100.25

05-10-2001, 10:06 AM	#8
thunderbolt Registered Member Join Date: Oct 1998 Location: Houston, TX, USA Posts: 380	I have heard alot of stories over the years of rebuilt 289's running hot in older mustangs. Don't know why, my stock one ran around the T on the temp guage all the time. Anyway, I would get a total cooling system overhaul beginning with the radiatior. Have it cleaned out, rodded out if need be. Change your thermostat to a new one and get a new radiator cap. If the radiator is bad, replace it with at least a 3 row unit. Aluminum is expensive but has much better heat radiating qualities, and is lighter. If you replace the water pump, go with an aluminum unit. If you are still warm, think about the water wetter. If your cooling system is up the snuff, you may have an engine problem, probably insufficient cleaning at the rebuild. This last problem is probably not it but keep it in mind if all else seems to fail.

05-10-2001, 12:21 PM	#9
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	you are running the fan shroud? that makes a difference at highway speed.. as for a rebuild... if it's .040 over, it's gonna run hot... might look into getting the radiator checked too.. ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives stock shorties stock cam, 1.7's 14.06@100.21, 255RWHP on a hot day 265 on the mph/weight chart

05-10-2001, 09:52 PM	#10
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Food for thought. Factory pumps are designed for maximum flow around 2500 RPM's. I Drag race my Stang and cut blades from the impeller, getting the cool I need. At a higher RPM a stock pump cavitates the water reducing flow. Lost yet? A clutch fan is working about the same as its counter part at 2500 RPM's. So at the high revs the fan really becomes less a part of cooling as your pump spins the same with either fan. At highway speeds where are your RPM's at? Above 2500? If so,I would go with a performance pump that moves a higher volume at higher revs. Water wetter does work. I would stay with the clutch and look into the pump. A larger radiator is always good. My head hurts now.

05-12-2001, 02:27 PM	#11
67 shadetree mechanic Registered Member Join Date: May 2001 Location: Fort Worth Texas Posts: 4	Is the radiator new or does it need replacing? Is anything restricting air infront of the radiator? Is the fan shroud missing? Is the thermosat working properly? Is any of the water hoses restricting water flow? Are you losing any water? Just a few experiences I've had in the past... My guess is the fan/clutch are not the problem but of course I haven't seen or know anything about your car. Good luck.