electric fan temp sensor

[38fordcoupe]

I've run a electric fan on my car for some time. The temp sensor was mounted in the radiator top neck . As per instructions . It worked great for about 5 years before it died. No biggy, I just replaced with a new one.
The new one lasted about a year and shot craps at the HAMB drags. By-passed adj. control and have been manually working fan. I got a new one  and the instructions say to mount on backside of radiator.  Picked a spare up at a swap meet and it says to mount where drain cock is located.  Are all of these locations acceptable? I always thought the top hose area was the most accurate. What do you guys think?

[Sean]

I run mine manually all the time. As long as I'm moving, it stays around 180 degrees, so the only time I switch it on is while setting in traffic, or going through the drivethrough at a restaurant.

When I first switched to an electric fan, I tried one of those switches like you're talking about and never could get it to work.

[Crosley.In.AZ]

mine is an adjustable unit with a probe through the fins of the rad.  I have no drain on this rad.

I adjusted it to run the fan past the thermostat temp. It rarely runs at road speed, comes on at a stop. We will see what the sumer heat does to it.

First unit that has worked real well for me.

Carquest is where I bought mine.... HTR-77528 was the part number.  48 bux plus tax

[38fordcoupe]

mine is an adjustable unit with a probe through the fins of the rad.  I have no drain on this rad.

I adjusted it to run the fan past the thermostat temp. It rarely runs at road speed, comes on at a stop. We will see what the sumer heat does to it.

First unit that has worked real well for me.

Carquest is where I bought mine.... HTR-77528 was the part number.  48 bux plus tax

Did you put it at the top or bottom of radiator

[WZ JUNK]

I've run a electric fan on my car for some time. The temp sensor was mounted in the radiator top neck . As per instructions . It worked great for about 5 years before it died. No biggy, I just replaced with a new one.
The new one lasted about a year and shot craps at the HAMB drags. By-passed adj. control and have been manually working fan. I got a new one  and the instructions say to mount on backside of radiator.  Picked a spare up at a swap meet and it says to mount where drain cock is located.  Are all of these locations acceptable? I always thought the top hose area was the most accurate. What do you guys think?

I usually use a Dodge mini van sensor that turns on at 185 degrees.   I place it in the head on a Chevy and I wire it to the fan relay to operate on the ground side of the relay.  To override the switch and operate the fan manually you only need to run a connecting wire to a toggle and then to ground.

[Crosley.In.AZ]

Did you put it at the top or bottom of radiator

the hot water enters the top - drivers side of the aluminum  radiator.  the temp probe is near that area through the fins

[enjenjo]

If you have a radiator with top and bootom tanks, the probe should be at or near the bottom.

[Jbird]

I've got the same one John(WZJUNK) has. It's screwed into the right hand head between #6 & #8 cylinder. I bought it at a hot rod shop, about fifty bucks, probably been a bunch cheaper from the Dodge dealer.
   Jbird

[X38]

I've got a Windsor in a 32, never a heat problem, 14" electric fan at top behind rad, Hotronics fan switch screws into inlet manifold next to temp guage sender (this is good as it keeps all  the wiring together). Switches on at 210 off at 195 (I think) and only does so very rarely, eg bumper to bumper traffic in summer. Most time engine sits at 180.

[WZ JUNK]

I've got the same one John(WZJUNK) has. It's screwed into the right hand head between #6 & #8 cylinder. I bought it at a hot rod shop, about fifty bucks, probably been a bunch cheaper from the Dodge dealer.
   Jbird

I think they are less than $10 at the auto parts store.  That one of the reasons I use them.

[BELLM]

I had a new Painless switch in the roadster, about 5 hrs on the engine & it went out.  Overheated in traffic @ Roundup.  Put a toggle switch in, turn it on in traffic, off on highway, works great.

[HOTRODSRJ]

I got a new one  and the instructions say to mount on backside of radiator.  Picked a spare up at a swap meet and it says to mount where drain cock is located.  Are all of these locations acceptable? I always thought the top hose area was the most accurate. What do you guys think?

All fan sensors are rated or "degreed" (eg. such as 180 or 195*) for intake type of sensing...or at least as close to the outlet of the block.  All of the OEMs sense this way or at calibrated cylinder locations.

The exit at the intake is indeed the hottest and most accurate position to place your sensor. It not only is the hottest, but also monitors BOTH heads and engine block banks.  The head position MAY be fairly accurate, but usually the addition of headers will "heat taint" the sensor into thinking its hotter than the coolant really is. This also does NOT monitor both sides of the engine which is inherently a problem. You could have a problem on the other side of the engine and never see it on the gauge.

The bottom of the radiator is the worst place and here's why.  The bottom temps are solely dependent on the outside ambient air temps and total airflow.  If you wait to turn a fan on at 185 degrees and the entire radiator is "soaked" to that temperature, obviously the engine temperature is going to suffer and see temperatures way in excess of that.  You can get adjustable thermostats that can be calibrated to anticipate your wanted outlet temperatures tho and these seen to work okay.

[Okiedokie]

WZ JUNK, got a part number or any other info on the Dodge mini van sensor?

[WZ JUNK]

WZ JUNK, got a part number or any other info on the Dodge mini van sensor?

Check this information and the specification when you go to the parts store.   Crysler # 520923   or Standard brand # GS87  I think they have 1/2" NPT

If this switch does not come on when you like, they can look these up in their specs. book and find another that will fit your application.  Some of these switches have 2 terminals and some have one.  I like to use a one terminal and wire the relay to work on the ground side of the circuit for the trigger to turn the fan on.  This also makes it easier to run a wire to a toggle switch and then to ground to turn the fan on manually.

[alchevy]

Has anyone ever used the fan switch made by Centronics? Speedway has them in their catalog.

CLIK here