Electric Fan switch location - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Edmond · 06-09-2002, 11:04 AM

I have found an switch and I was wondering if I could put
it in on the intake manifold? (See picture)
Or is the best location on the radiator?

Thanks.

Cya,
Edmond

Edmond · 06-09-2002, 11:06 AM

Sorry, but there was no picture...

I hope this time it works.....

Cya,
Edmond

XXL · 06-09-2002, 11:21 AM

I think you'd be better off with the switch on the radiator. The fan is intended to cool the water in the radiator based on its temperature. The water in the manifold is often a completely different temperature... both from the fact that it is separately regulated by the thermostat and because it is inherently a different temperature since it's in the engine and hasn't had a chance to cool off as much as the water that's traveled to the radiator.

Just my 2 cents. I hope it helps,

Kenneth

383 Stroker · 06-09-2002, 12:05 PM

I would put it in one of the heads, or you can put it in the intake. I have mine in one of the heads.

PanelDeland · 06-09-2002, 09:59 PM

I would put it in the intake or a head.You want to keep track of "ENGINE TEMP" not radiator temp.

Right?

XXL · 06-09-2002, 10:03 PM

I guess I missed the point of the original question. I thought you were talking about the thermal switch that cuts on and off the electric fans.

If so, the fans are there to regulate the temperature of the fluid in the RADIATOR. There's no direct correlation to the fluid that's in the engine. The thermostat in the manifold is responsible for regulating water to the engine. And when it needs cooler fluid, it opens up and expects the appropriate temperature fluid from the radiator.

Kenneth

Longhorn Man · 06-09-2002, 10:22 PM

The fan is to cool the coolant in the radiator, therfor, it needs to know the temp of the coolant in the radiater, not the engine.

BobbyK · 06-10-2002, 04:24 AM

Why is the sender for the temp. gauge threaded into the head then?
If you have a working coolant system the temp. in the rad. (inlet) will be approx. what temp. the thermostat is.
I personally don't care what the temp in the rad is as long as the temp in the engine is within normal limits.
If your thermostat malfunctions the temp. in the rad can be drastically different from the eng. temp. So if your running a temp. controlled fan and the rad temp is normal but the eng temp is up the fan may shut off because the rad. temp is o.k.(did that make sense?)
Anyway I threaded my fan thermostat in the head.

XXL · 06-10-2002, 08:10 AM

Quote:

Originally posted by BobbyK
Why is the sender for the temp. gauge threaded into the head then?
If you have a working coolant system the temp. in the rad. (inlet) will be approx. what temp. the thermostat is.
I personally don't care what the temp in the rad is as long as the temp in the engine is within normal limits.
If your thermostat malfunctions the temp. in the rad can be drastically different from the eng. temp. So if your running a temp. controlled fan and the rad temp is normal but the eng temp is up the fan may shut off because the rad. temp is o.k.(did that make sense?)
Anyway I threaded my fan thermostat in the head.

But now we're talking about 2 different things. The temp gauge is designed to tell you how hot the ENGINE is. The fan switch is designed to turn on the fan. And in your example, if the thermostat is stuck (closed), then it doesn't help one bit to have the fan switch on the manifold.

You're correct that the two temps can be drastically different. That is precisely why there is a thermostat in the manifold... to regulate that difference. Operating temp for the engine is different than the reservoir fluid of the radiator... hence warmups when you start your vehicle.

Mike C · 06-10-2002, 08:33 AM

It needs to go into the radiator. As noted previously, water in the motor is controlled by the thermostat. The water in the radiator is cooled by the fan. Take for example a cold 27 def F day. The engine temp is 195 deg because of the thermostat and you turn the fan on at 180, but the temp in the radiator is already 120 degrees. The fan runs cooling the water even further then the thermostat opens releasing 50 degree COLD water into the 195 deg engine, shocking the block causing localized shrinking of the cast iron and cracking the block... This is an extreme example, but the fan switch goes in the RADIATOR and not the block. It is more important in cold weather when the temp difference between the radiator and the engine is highest. Also having it in the radiator should let the engine warm up faster.

tom hand · 06-10-2002, 08:55 AM

All great theroys but I don't think it makes a rats a$$ difference where you screw it in. As long as it in coolant it will work. Hell their is more temp differance between the top radiator hose and the bottom one, than probably any where else in the system. And I have worked on GM cars were the factory one is in the head.

BobbyK · 06-10-2002, 09:15 AM

Rat's ass...that's funny.
I was just going to say G.M. put's them in the head.

diggin69 · 06-10-2002, 10:42 AM

Did I hear Somebody say HEAD!!!!!! LOL....

Mudder · 06-10-2002, 12:41 PM

YEPPERS!!!!! I"M CONFUSED!

XXL · 06-10-2002, 07:24 PM

Quote:

Originally posted by tom hand
All great theroys but I don't think it makes a rats a$$ difference where you screw it in. As long as it in coolant it will work. Hell their is more temp differance between the top radiator hose and the bottom one, than probably any where else in the system. And I have worked on GM cars were the factory one is in the head.

To those of you who insist that the fan switch goes in the head, checking the Flex-A-Lite site for more definitive information nets the following... fan installation instructions

Now, they may be incorrect, but I'm going with them since they make the things for a living.

Kenneth

tom hand · 06-10-2002, 08:52 PM

Apples and oranges. That is a sensor bulb that is designed to be mounted in a radiator hose. Here a a thermostatic switch that is designed to be mounted in the head of an f-body. I think GM built a couple of those things.

383 Stroker · 06-10-2002, 09:10 PM

My fan thermostat probe is made by Painless Wiring. It is made to go in the head. That Flex-A-Lite fan thermostat probe is made to go in the radiator. I like the kind I have, it works perfect, comes on exactly at 185* and turns of at 170*. Look under the hood of any newer car and you will see, the fan thermostat probe is in the intake or head.

XXL · 06-10-2002, 09:14 PM

Quote:

Originally posted by 383 Stroker
Look under the hood of any newer car and you will see, the fan thermostat probe is in the intake or head.

How new does it have to be? My wife's 2001 Subaru has it sticking into the side of the radiator tank.

BTW, this appears to be turning into a urinating contest, so I'm gonna bow out (and go install my electric fan switch on the radiator like the manufacturer of the product tells me in their instructions

).

Kenneth

383 Stroker · 06-10-2002, 09:21 PM

I'm sorry, I should have said most newer cars. Almost all GM and Ford cars have it in the intake or head.

06-09-2002, 11:04 AM	#1
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,062	Electric Fan switch location I have found an switch and I was wondering if I could put it in on the intake manifold? (See picture) Or is the best location on the radiator? Thanks. Cya, Edmond __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- Capelle a/d IJssel, The Netherlands

06-09-2002, 11:06 AM	#2
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,062	Sorry, but there was no picture... I hope this time it works..... Cya, Edmond Attached Images __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- Capelle a/d IJssel, The Netherlands

06-09-2002, 11:21 AM	#3
XXL Señor Member Join Date: May 2002 Location: Edge of the world Posts: 5,367	I think you'd be better off with the switch on the radiator. The fan is intended to cool the water in the radiator based on its temperature. The water in the manifold is often a completely different temperature... both from the fact that it is separately regulated by the thermostat and because it is inherently a different temperature since it's in the engine and hasn't had a chance to cool off as much as the water that's traveled to the radiator. Just my 2 cents. I hope it helps, Kenneth __________________ Craigslist \| ebay \| Engrishtees \| www.myattitudesucks.com \| Follow me on Twitter

06-09-2002, 12:05 PM	#4
383 Stroker Registered User Join Date: Aug 2001 Location: Jesup, GA Posts: 571	I would put it in one of the heads, or you can put it in the intake. I have mine in one of the heads. __________________ Video's of my Truck Racing 1967 C-10, 383ci Sbc, TH350, 3200 stall, 3.73 gear

06-09-2002, 09:59 PM	#5
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	I would put it in the intake or a head.You want to keep track of "ENGINE TEMP" not radiator temp. Right? __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

06-09-2002, 10:03 PM	#6
XXL Señor Member Join Date: May 2002 Location: Edge of the world Posts: 5,367	I guess I missed the point of the original question. I thought you were talking about the thermal switch that cuts on and off the electric fans. If so, the fans are there to regulate the temperature of the fluid in the RADIATOR. There's no direct correlation to the fluid that's in the engine. The thermostat in the manifold is responsible for regulating water to the engine. And when it needs cooler fluid, it opens up and expects the appropriate temperature fluid from the radiator. Kenneth __________________ Craigslist \| ebay \| Engrishtees \| www.myattitudesucks.com \| Follow me on Twitter

06-09-2002, 10:22 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The fan is to cool the coolant in the radiator, therfor, it needs to know the temp of the coolant in the radiater, not the engine.

06-10-2002, 04:24 AM	#8
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Why is the sender for the temp. gauge threaded into the head then? If you have a working coolant system the temp. in the rad. (inlet) will be approx. what temp. the thermostat is. I personally don't care what the temp in the rad is as long as the temp in the engine is within normal limits. If your thermostat malfunctions the temp. in the rad can be drastically different from the eng. temp. So if your running a temp. controlled fan and the rad temp is normal but the eng temp is up the fan may shut off because the rad. temp is o.k.(did that make sense?) Anyway I threaded my fan thermostat in the head. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE Last edited by BobbyK; 06-10-2002 at 07:05 AM.

06-10-2002, 08:33 AM	#10
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,714	It needs to go into the radiator. As noted previously, water in the motor is controlled by the thermostat. The water in the radiator is cooled by the fan. Take for example a cold 27 def F day. The engine temp is 195 deg because of the thermostat and you turn the fan on at 180, but the temp in the radiator is already 120 degrees. The fan runs cooling the water even further then the thermostat opens releasing 50 degree COLD water into the 195 deg engine, shocking the block causing localized shrinking of the cast iron and cracking the block... This is an extreme example, but the fan switch goes in the RADIATOR and not the block. It is more important in cold weather when the temp difference between the radiator and the engine is highest. Also having it in the radiator should let the engine warm up faster. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

06-10-2002, 08:55 AM	#11
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	All great theroys but I don't think it makes a rats a$$ difference where you screw it in. As long as it in coolant it will work. Hell their is more temp differance between the top radiator hose and the bottom one, than probably any where else in the system. And I have worked on GM cars were the factory one is in the head. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

06-10-2002, 09:15 AM	#12
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Rat's ass...that's funny. I was just going to say G.M. put's them in the head. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

06-10-2002, 10:42 AM	#13
diggin69 Southern but in Ohio!!!! Join Date: Jan 2002 Location: Eaton,Oh. 45320 Posts: 467	Did I hear Somebody say HEAD!!!!!! LOL.... __________________ 1969 C/10 3/4 ton 4x4 longbed custom, frame made from a 79 1972 custom-10 half/ton longbed 1980 1/2 ton 4x4 all original 350/350/205 with air Eaton,Oh rebelryder@hotmail.com

06-10-2002, 12:41 PM	#14
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Confused? YEPPERS!!!!! I"M CONFUSED!

06-10-2002, 08:52 PM	#16
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Apples and oranges. That is a sensor bulb that is designed to be mounted in a radiator hose. Here a a thermostatic switch that is designed to be mounted in the head of an f-body. I think GM built a couple of those things. Attached Images __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

06-10-2002, 09:10 PM	#17
383 Stroker Registered User Join Date: Aug 2001 Location: Jesup, GA Posts: 571	My fan thermostat probe is made by Painless Wiring. It is made to go in the head. That Flex-A-Lite fan thermostat probe is made to go in the radiator. I like the kind I have, it works perfect, comes on exactly at 185* and turns of at 170*. Look under the hood of any newer car and you will see, the fan thermostat probe is in the intake or head. __________________ Video's of my Truck Racing 1967 C-10, 383ci Sbc, TH350, 3200 stall, 3.73 gear



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06-10-2002, 09:21 PM	#19
383 Stroker Registered User Join Date: Aug 2001 Location: Jesup, GA Posts: 571	I'm sorry, I should have said most newer cars. Almost all GM and Ford cars have it in the intake or head. __________________ Video's of my Truck Racing 1967 C-10, 383ci Sbc, TH350, 3200 stall, 3.73 gear

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