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Placement of temp sensor for cooling fan

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I'll post a pic of mine when it comes back. The freeze plug approach seemed reasonable when they described what they had done.

Now of course I have a useless hole in the bottom of my rad!
 
2W,

Ron Davis will not put a bung in the radiator for a sensor. That's what sort of started this thread.

71TR,

They suggested splitting that connection at the head and putting one there or in the block wherever was convenient.

This is what I would get (almost, not quite for TR6) custom made to replace the TR6 rad. The 16" fan puller will go directly into the center of the big hole, making the inner shroud act as a manifold to direct air to 100% of the radiator core.



Now I have to see if it will fit before ordering it.
 
That shroud is actually to help direct air away from the radiator via the fan. Keeps turbulent air from fouling the flow as it comes into the engine bay side. The standard TR6 shroud between the grill and the front of the rad directs air though the radiator.
 
Shawn, my bad. I did state that it was a "puller" fan and should have said to "pull of the air over 100% of the core" rather than to direct it in my explanation. Late night post...sorry.
 
Brosky: That rad is just that...RAD! Hey, that thing
will have he right look to compliment each of your
other mods. Looks a very coool.
 
2W,

That's just a sample, but the rad that I would use if it fits will be similar, but with the inlet and outlet in the proper position, rather than what is shown here.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]
2. the radiator is always much cooler than the block. The radiator doesn't overheat, the engine does, so they say to install the sensor in the head or block, but never in the radiator or hoses.
[/QUOTE]
An entertaining notion, particularly coming from "pros".

The purpose of the fan is to pull cooling air through the radiator when needed. This cooling air is needed when the radiator starts getting hot. So when the radiator, not the engine, starts getting heated up, the cooling fan kicks in, pulling air through the radiator, cooling the radiator back down.

That's why every auto maker out there places the electric fan switch in the radiator, usually at the bottom or end if it's a sidedraft radiator.

A sensor in the head is usefull for telling the ECU and driver information about the heat of the engine, but not for switching on the cooling fan for a hot radiator.
 
foxtrapper said:
That's why every auto maker out there places the electric fan switch in the radiator, usually at the bottom or end if it's a sidedraft radiator.
Click to expand...

Well, that's not true of all the automakers. My VW GTi that I used to own, had the fan switch in the bottom of the radiator, as well as some other cars I have owned. But now, I see that they are moving them around to different locations and some are just using the info supplied to the ECU from the engine temp switch for turning on the fan. My Miata has three temp switches. One for the gauge, one for the ECU, and one for the fan. They are all in different locations. The one for the fan is in the thermostat housing.

Personally, I don't really think it matters where you put the switch, just so long as it trips at the appropriate time...when the temp starts to rise above normal. If you can do the in the hose, the radiator, or the thermo housing, what difference does it make? That's why an adjustable switch is a good thing. You can set it according to your car. And, just in case, be sure to install an in dash switch so you can turn the fan on whenever it might be needed. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
martx-5 said:
Personally, I don't really think it matters where you put the switch, just so long as it trips at the appropriate time...when the temp starts to rise above normal. If you can do the in the hose, the radiator, or the thermo housing, what difference does it make? That's why an adjustable switch is a good thing. You can set it according to your car.
Click to expand...

Which is why the auto manufacturers do what they do. For all the different places that the sensors are put, you can bet there are different temperature settings that trip those switches. A switch designed to be placed on the incoming side of a radiator will surely cause an overheating problem by not turning fans on in time if its placed on the outgoing side of the radiator. The adjustable switches are excellent for aftermarket purposes and true universality. If thats a word...? /bcforum/images/%%GRAEMLIN_URL%%/crazy.gif
 
Both my BMW and my Saab have the fan sensor in the radiator, near the bottom hose. The Saab uses electric fans exclusively. The BMW uses both a viscous coupling on a water pump mounted fan, and two-speed electric fans in front of the radiator. Its electric fans will start at low speed when the A/C is turned on, and will start at high speed if the thermal switch is tripped, which happens only in stop and go driving in the summertime.

Both cars also use another water temperature sensor mounted in the block for the Bosch fuel injection systems.

Scott
 
Well, the RD comments did stir up some lively comments.

Thanks to all.

I'll probably still flip the coin, because I think that everyone is correct in one way or another.
 
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