View Poll Results: Overheating
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Overheating
September 20th, 2020, 06:13 PM
#1
Registered User
Thread Starter
Join Date: Sep 2020
Posts: 9
Overheating
Hello, I have a 1972 cutlass with a 455.i joined the group cause I have no were else to turn. Having overheating issues.
what I have done so far...
1- aluminum rad
2- dual electric fans both pulling
3- high flow water pump
4- high flow thermostat
5- new rad cap
had my timing adjusted right and carb adjust as well.
please help
what I have done so far...
1- aluminum rad
2- dual electric fans both pulling
3- high flow water pump
4- high flow thermostat
5- new rad cap
had my timing adjusted right and carb adjust as well.
please help
September 20th, 2020, 06:45 PM
#2
Registered User
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 14,168
My bet would be #2, as in not sufficient air flow.
But you need to be more specific about the overheating - does it happen at low speeds/idle or at cruising /highway speeds? Those have very different causes.
But you need to be more specific about the overheating - does it happen at low speeds/idle or at cruising /highway speeds? Those have very different causes.
September 21st, 2020, 06:13 AM
#10
Registered User
Join Date: Jan 2010
Location: central Indiana
Posts: 5,343
Personally, I wouldn’t pay a dime for 10 aftermarket parts store electric fans. Their CFM claims are very optimistic. If you absolutely insist on aftermarket fans, either adapt fans from a late model full sized car or truck, or the expensive aftermarket fans like Spal, etc.
In my opinion, nothing beats a big fan with a thermal fan clutch. The fan basically freewheels until the radiator gets hot enough to engage the fan clutch, then you can hear the tornado going thru the radiator. Actually, I will revise my statement: the only thing that beats a thermal fan clutch is an ELECTRIC fan clutch. When big trucks use electric fans, I’ll reconsider my position.
Ad for the bullshit theory of mechanical fans robbing power, I have run my car at the track many times both with and without the fan, zero change. I’m not talking about one weekend removing the fan, I’m saying I’ll make a couple passes to establish a baseline. then remove the fan and make a couple more passes. No significant (or even what I would consider insignificant) change. Certainly not the 20-25 hp they supposedly rob. Obviously, if the engine was overheating, or running hot enough to engage the clutch, I would expect a drop in performance. Same thing with an alternator cutout switch, once the battery is fully changed, the alternator isn’t doing much.
Before spending a dime on anything, look over the car. Are all the factory baffles installed around the radiator and bumper? Those tar paper baffles are designed to funnel airflow thru the radiator. Without them, air might go under, over, or around the radiator instead of thru the core. Are the correct pulleys installed?
How is the tune? Is the engine lean, timing off, vacuum leaks, etc?
When exactly does it get hot? Btw, 225 at idle isn’t terrible. If it cools down once you start moving, that suggests a airflow issue.
if it warms up driving, then that suggests insufficient cooling capacity. Either the radiator is too small, the engine is creating heat faster than the radiator can dispose of it (is the spring In the lower hose installed?) thermostat stuck or won’t fully open, etc. Is the lower “chin spoiler” installed or in good shape? It’s purpose is to create a low pressure area behind the radiator to funnel air thru the radiator, kinda like a airplane wing. I can’t tell you how many people take them off because they don’t like the way they look, or have been mangled by running into parking lot barricades.
These cars didn’t overheat when new. If they do now, most of the time the cause is because someone threw away or modified un-needed” parts over the years. When I was younger I believed a lot of the rumors and bench-racing bull, and over the years I have had to spend money to “fix” what I screwed up.
In my opinion, nothing beats a big fan with a thermal fan clutch. The fan basically freewheels until the radiator gets hot enough to engage the fan clutch, then you can hear the tornado going thru the radiator. Actually, I will revise my statement: the only thing that beats a thermal fan clutch is an ELECTRIC fan clutch. When big trucks use electric fans, I’ll reconsider my position.
Ad for the bullshit theory of mechanical fans robbing power, I have run my car at the track many times both with and without the fan, zero change. I’m not talking about one weekend removing the fan, I’m saying I’ll make a couple passes to establish a baseline. then remove the fan and make a couple more passes. No significant (or even what I would consider insignificant) change. Certainly not the 20-25 hp they supposedly rob. Obviously, if the engine was overheating, or running hot enough to engage the clutch, I would expect a drop in performance. Same thing with an alternator cutout switch, once the battery is fully changed, the alternator isn’t doing much.
Before spending a dime on anything, look over the car. Are all the factory baffles installed around the radiator and bumper? Those tar paper baffles are designed to funnel airflow thru the radiator. Without them, air might go under, over, or around the radiator instead of thru the core. Are the correct pulleys installed?
How is the tune? Is the engine lean, timing off, vacuum leaks, etc?
When exactly does it get hot? Btw, 225 at idle isn’t terrible. If it cools down once you start moving, that suggests a airflow issue.
if it warms up driving, then that suggests insufficient cooling capacity. Either the radiator is too small, the engine is creating heat faster than the radiator can dispose of it (is the spring In the lower hose installed?) thermostat stuck or won’t fully open, etc. Is the lower “chin spoiler” installed or in good shape? It’s purpose is to create a low pressure area behind the radiator to funnel air thru the radiator, kinda like a airplane wing. I can’t tell you how many people take them off because they don’t like the way they look, or have been mangled by running into parking lot barricades.
These cars didn’t overheat when new. If they do now, most of the time the cause is because someone threw away or modified un-needed” parts over the years. When I was younger I believed a lot of the rumors and bench-racing bull, and over the years I have had to spend money to “fix” what I screwed up.
September 21st, 2020, 06:31 AM
#11
Registered User
Join Date: Aug 2018
Location: Middletown, OH
Posts: 48
Personally, I wouldn’t pay a dime for 10 aftermarket parts store electric fans. Their CFM claims are very optimistic. If you absolutely insist on aftermarket fans, either adapt fans from a late model full sized car or truck, or the expensive aftermarket fans like Spal, etc.
In my opinion, nothing beats a big fan with a thermal fan clutch. The fan basically freewheels until the radiator gets hot enough to engage the fan clutch, then you can hear the tornado going thru the radiator. Actually, I will revise my statement: the only thing that beats a thermal fan clutch is an ELECTRIC fan clutch. When big trucks use electric fans, I’ll reconsider my position.
Ad for the bullshit theory of mechanical fans robbing power, I have run my car at the track many times both with and without the fan, zero change. I’m not talking about one weekend removing the fan, I’m saying I’ll make a couple passes to establish a baseline. then remove the fan and make a couple more passes. No significant (or even what I would consider insignificant) change. Certainly not the 20-25 hp they supposedly rob. Obviously, if the engine was overheating, or running hot enough to engage the clutch, I would expect a drop in performance. Same thing with an alternator cutout switch, once the battery is fully changed, the alternator isn’t doing much.
Before spending a dime on anything, look over the car. Are all the factory baffles installed around the radiator and bumper? Those tar paper baffles are designed to funnel airflow thru the radiator. Without them, air might go under, over, or around the radiator instead of thru the core. Are the correct pulleys installed?
How is the tune? Is the engine lean, timing off, vacuum leaks, etc?
When exactly does it get hot? Btw, 225 at idle isn’t terrible. If it cools down once you start moving, that suggests a airflow issue.
if it warms up driving, then that suggests insufficient cooling capacity. Either the radiator is too small, the engine is creating heat faster than the radiator can dispose of it (is the spring In the lower hose installed?) thermostat stuck or won’t fully open, etc. Is the lower “chin spoiler” installed or in good shape? It’s purpose is to create a low pressure area behind the radiator to funnel air thru the radiator, kinda like a airplane wing. I can’t tell you how many people take them off because they don’t like the way they look, or have been mangled by running into parking lot barricades.
These cars didn’t overheat when new. If they do now, most of the time the cause is because someone threw away or modified un-needed” parts over the years. When I was younger I believed a lot of the rumors and bench-racing bull, and over the years I have had to spend money to “fix” what I screwed up.
In my opinion, nothing beats a big fan with a thermal fan clutch. The fan basically freewheels until the radiator gets hot enough to engage the fan clutch, then you can hear the tornado going thru the radiator. Actually, I will revise my statement: the only thing that beats a thermal fan clutch is an ELECTRIC fan clutch. When big trucks use electric fans, I’ll reconsider my position.
Ad for the bullshit theory of mechanical fans robbing power, I have run my car at the track many times both with and without the fan, zero change. I’m not talking about one weekend removing the fan, I’m saying I’ll make a couple passes to establish a baseline. then remove the fan and make a couple more passes. No significant (or even what I would consider insignificant) change. Certainly not the 20-25 hp they supposedly rob. Obviously, if the engine was overheating, or running hot enough to engage the clutch, I would expect a drop in performance. Same thing with an alternator cutout switch, once the battery is fully changed, the alternator isn’t doing much.
Before spending a dime on anything, look over the car. Are all the factory baffles installed around the radiator and bumper? Those tar paper baffles are designed to funnel airflow thru the radiator. Without them, air might go under, over, or around the radiator instead of thru the core. Are the correct pulleys installed?
How is the tune? Is the engine lean, timing off, vacuum leaks, etc?
When exactly does it get hot? Btw, 225 at idle isn’t terrible. If it cools down once you start moving, that suggests a airflow issue.
if it warms up driving, then that suggests insufficient cooling capacity. Either the radiator is too small, the engine is creating heat faster than the radiator can dispose of it (is the spring In the lower hose installed?) thermostat stuck or won’t fully open, etc. Is the lower “chin spoiler” installed or in good shape? It’s purpose is to create a low pressure area behind the radiator to funnel air thru the radiator, kinda like a airplane wing. I can’t tell you how many people take them off because they don’t like the way they look, or have been mangled by running into parking lot barricades.
These cars didn’t overheat when new. If they do now, most of the time the cause is because someone threw away or modified un-needed” parts over the years. When I was younger I believed a lot of the rumors and bench-racing bull, and over the years I have had to spend money to “fix” what I screwed up.
September 21st, 2020, 08:41 AM
#13
Registered User
Thread Starter
Join Date: Sep 2020
Posts: 9
A lot to take in.i ran the car this morning I the drive way. The temp gauge got up to 225. I used a fluke thermo gun an the block was reading 234. Ran it on the freeway an it dropped to 140. Then back to 225 in stop an go traffic back to the house.
thank you guys.
thank you guys.
September 21st, 2020, 08:55 AM
#14
Registered User
Join Date: Jan 2010
Location: central Indiana
Posts: 5,343
That’s a HUGE swing in temp, I’d suspect a bunch of air trapped in the cooling system.
The most idiot proof method I have found for eliminating air is to elevate the pass corner of the car, get it as high as possible. Top off the coolant, leave the radiator cap off. With the radiator cap off, coolant will naturally displace air, forcing it out the filler neck.
The most idiot proof method I have found for eliminating air is to elevate the pass corner of the car, get it as high as possible. Top off the coolant, leave the radiator cap off. With the radiator cap off, coolant will naturally displace air, forcing it out the filler neck.
September 21st, 2020, 10:41 AM
#16
Administrator
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 40,795
Air in the cooling system usually results in large wild rapid swings in temp on the gauge. I doubt you have any air pockets. If your pulling 140 on the highway and 240 in traffic it points to a lack of airflow through the radiator at lower speeds. Can you post a few pictures of your setup?
September 21st, 2020, 11:45 AM
#19
Moderator
Join Date: Jul 2007
Location: Edmond, OK
Posts: 16,171
Did the car overheat when you were using the clutch fan?
Don't bother getting a Summit or Jegs cheapie electric fan. You can find one that is cheaper and will flow more air at the salvage yard. Check out this thread:
https://classicoldsmobile.com/forums...r-fans-141678/
BTW, how is the fan secured to your radiator? If you used the electric fan "zip-ties" through the radiator core that wouldn't cause you overheating problem but would lead to problems in the future.
Don't bother getting a Summit or Jegs cheapie electric fan. You can find one that is cheaper and will flow more air at the salvage yard. Check out this thread:
https://classicoldsmobile.com/forums...r-fans-141678/
BTW, how is the fan secured to your radiator? If you used the electric fan "zip-ties" through the radiator core that wouldn't cause you overheating problem but would lead to problems in the future.
September 24th, 2020, 04:49 AM
#21
Registered User
Join Date: Aug 2019
Posts: 1,075
Hello, I have a 1972 cutlass with a 455.i joined the group cause I have no were else to turn. Having overheating issues.
what I have done so far...
1- aluminum rad
2- dual electric fans both pulling
3- high flow water pump
4- high flow thermostat
5- new rad cap
had my timing adjusted right and carb adjust as well.
please help
what I have done so far...
1- aluminum rad
2- dual electric fans both pulling
3- high flow water pump
4- high flow thermostat
5- new rad cap
had my timing adjusted right and carb adjust as well.
please help
September 24th, 2020, 07:24 AM
#22
Registered User
Join Date: Jul 2009
Location: Dallas-Fort Worth
Posts: 3,129
CFM ratings on electric fans is without nothing in front of it. Example:If you have a 3-4 row rad and a AC condenser in front of that, your actual CFM rating is highly compromised. I have learned too that extra rows does not necessarily mean cooler engine temps either. The fin count on the rad you choose can play into this too. I have read from some Chevelle Forums that Champion rads and a few others the fins are to close together and that can possibly play a part of some cases of overheating. Some fans cannot pull enough air through all 3-4 rows and a AC condenser and cool the engine. I'm not an aerodynamic engineer by any stretch, but ask me how I know-I have just about figured out how to cool down the 400E in the 64 F-85 build..Currently the 3 row Champion rad with an AC condenser in front of it will not keep the 400E cool enough for me in 100 degree temps with the AC on. As in this case of mine I'm going to cut the bottom of the rad core support off on each side lower it about 3 inches , weld it back together and add a bigger rad. Compared to later model Olds A-body's with 455's, a 64 radiator core support is a one year only for a 330 small block. Hopefully that will do it. But this time around I'm going to look up a Cold Case, Griffin etc for a 2 row rad and Derale 4000 CFM dual 12 " fans. Will I have enough space will be another big factor-combined thickness of the rad and fans. Right now I only have less than 1/2 inch between the fans and the water pump pulley. Time will tell. Good luck..
September 24th, 2020, 08:45 AM
#24
Administrator
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 40,795
This indicates the radiator is fine and you have limited air flow at lower speeds and idle. How about some pictures of your setup. Fans, shroud, radiator front.
June 4th, 2021, 10:56 PM
#26
Registered User
Join Date: May 2009
Location: Northern California
Posts: 1,708
I’m late on this, but happy owner of 2 455 equipped cars. For 25 years or more I ran 160F thermostats & was pretty casual about shrouding & fans. I just switched to 180F thermostats and the cars run better. But t-stats alone are not the story. Here are the requirements which allow the higher temperature thermostats to work well.
I tried the electric fan route in the 80’s but the ones that zip tied through the radiator eventually caused a leak. Properly mounted and thermostat controlled, I’m sure electric fans would be good, maybe great. The manufacturers all use electric these days. There’s probably a reason. I went old school since it worked well for GM up until electric came along.
Over the past 5 years or so I got careful about the radiator fan shroud. I retrofitted 7 blade 18” fans in both of my cars. These mechanically drew a lot more air across the core. I also carefully selected Hayden clutch fans to locate the fans very close to the radiator and to cut in at lower temperature. Hayden has a wide variety of clutches, I used HD (heavy duty) not SD (standard duty) since they kicked in cooler. This has helped too. I want to say one of my cars has a 7474, but I’m probably off about the model number. Might be 4747…
I use the FlowKooler water pumps. I’m not a stickler for factory castings & correctness. I’d rather have a cool running car, than matching water pump numbers. The flowkooler pumps have a good impeller & aluminum disc on the back which seems to increase coolant flow. I believe this helps. These pumps have been on my cars for at least 8 or 10 years with no issues.
In ‘66 Olds cheaped out and had just 1 fan shroud design for big & little cars. This worked fine for Cutlasses, but only covered about 70% of the width of the wider big car radiators. 5 or 6 years ago, I augmented the ‘66 factory shrouds with an additional left hand side piece cut & donated from later 60’s Toronado shrouds and screwed/zip tied to the Toronado graft onto the main body of my ‘66 shrouds. More or less I bolted a “wing” on the driver’s side to cover the rad completely.
The other thing that helped my cars was redoing the masticated rubber curtains that more or less force air through the radiator core from the front rather than around the radiator on the sides, top and bottom. I got the raw materials from Fusick and more or less duplicated what the factory did with a bit more margin since I’d already bought the material and could force more air across the radiator core.
Fusick sells this rubber fabric by the roll. You pretty much make & install 2 side curtains, one bottom curtain, or you could make a giant U shaped piece to really nail it. If you get picky, wrap some rubber around the top corners too. The rubber curtains are more or less a front shroud.
After a bunch of reading, I refilled my radiators with a coolant mix of 70% water / 30% antifreeze / Water Wetter. In my neighborhood near San Francisco it’s the best solution I’ve seen in years. We never freeze here, so too little coolant isn’t a problem. I mainly worry about overheating in traffic. It seems that water transfers more heat than coolant, but you need coolant for it’s lubricating and anti-scaling components. Hence more water as overheating protection.
After _decades_ of worrying about sitting in traffic, I may finally be past the problem. On a recent 89F day, I went 2 hours in traffic and my engine temps never even hit 190. With a 180F thermostat. Great feeling having 1 less thing to worry about. Taking overheating worry out of the mix makes the cars _much_ more enjoyable.
Among the front curtains, good water pump, good coolant mix, full rear shroud, good fan, HD fan clutch, I got where I wanted to go. — An Olds 455 running on modern cr*p gas without much worrying about overheating even on what we think of as a hot day in traffic.
Hope this helps some of you
Cheers
cf
I tried the electric fan route in the 80’s but the ones that zip tied through the radiator eventually caused a leak. Properly mounted and thermostat controlled, I’m sure electric fans would be good, maybe great. The manufacturers all use electric these days. There’s probably a reason. I went old school since it worked well for GM up until electric came along.
Over the past 5 years or so I got careful about the radiator fan shroud. I retrofitted 7 blade 18” fans in both of my cars. These mechanically drew a lot more air across the core. I also carefully selected Hayden clutch fans to locate the fans very close to the radiator and to cut in at lower temperature. Hayden has a wide variety of clutches, I used HD (heavy duty) not SD (standard duty) since they kicked in cooler. This has helped too. I want to say one of my cars has a 7474, but I’m probably off about the model number. Might be 4747…
I use the FlowKooler water pumps. I’m not a stickler for factory castings & correctness. I’d rather have a cool running car, than matching water pump numbers. The flowkooler pumps have a good impeller & aluminum disc on the back which seems to increase coolant flow. I believe this helps. These pumps have been on my cars for at least 8 or 10 years with no issues.
In ‘66 Olds cheaped out and had just 1 fan shroud design for big & little cars. This worked fine for Cutlasses, but only covered about 70% of the width of the wider big car radiators. 5 or 6 years ago, I augmented the ‘66 factory shrouds with an additional left hand side piece cut & donated from later 60’s Toronado shrouds and screwed/zip tied to the Toronado graft onto the main body of my ‘66 shrouds. More or less I bolted a “wing” on the driver’s side to cover the rad completely.
The other thing that helped my cars was redoing the masticated rubber curtains that more or less force air through the radiator core from the front rather than around the radiator on the sides, top and bottom. I got the raw materials from Fusick and more or less duplicated what the factory did with a bit more margin since I’d already bought the material and could force more air across the radiator core.
Fusick sells this rubber fabric by the roll. You pretty much make & install 2 side curtains, one bottom curtain, or you could make a giant U shaped piece to really nail it. If you get picky, wrap some rubber around the top corners too. The rubber curtains are more or less a front shroud.
After a bunch of reading, I refilled my radiators with a coolant mix of 70% water / 30% antifreeze / Water Wetter. In my neighborhood near San Francisco it’s the best solution I’ve seen in years. We never freeze here, so too little coolant isn’t a problem. I mainly worry about overheating in traffic. It seems that water transfers more heat than coolant, but you need coolant for it’s lubricating and anti-scaling components. Hence more water as overheating protection.
After _decades_ of worrying about sitting in traffic, I may finally be past the problem. On a recent 89F day, I went 2 hours in traffic and my engine temps never even hit 190. With a 180F thermostat. Great feeling having 1 less thing to worry about. Taking overheating worry out of the mix makes the cars _much_ more enjoyable.
Among the front curtains, good water pump, good coolant mix, full rear shroud, good fan, HD fan clutch, I got where I wanted to go. — An Olds 455 running on modern cr*p gas without much worrying about overheating even on what we think of as a hot day in traffic.
Hope this helps some of you
Cheers
cf
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