coolant temp warning light add-in

I'd like to add a warning light/LED of some sort to let me know when the coolant temp has reached approx. 220 degrees. I've got a 95 with a 4.6 stroker running triple electric fans for cooling. It's working great, but I would like to have something to "signal" me when/if something were to go wrong with the setup and I wasn't paying attention to the gauges.

My thought was to somehow wire in an LED to the cts on the rear of the head that goes to the gauge without altering the signal to the gauge.

Has anyone out there done this? Any EEs out there that would know how to wire something like this up?

Thanks for any input.

K

95?

So your ECU gets temp data from a sender in the thermostat housing, right? The older Renix models had a sender on the driver's side of the block to send data to the ECU. If your engine has a boss (maybe even a tapped and plugged hole) where the Renix sender was located, you could just install a standard idiot light temp sender there and leave the gauge sender in the head alone.

The pre-90 renix system used a sensor in the radiator to directly switch a relay to turn on the elec. fan at 220 degrees. If you can find one of those sensors, called a "radiator temp switch" by the service manual, and rig it up in some sort of T-joint in a cooling hose, you could use that to turn on a light. the switch just closes the two wires, and that engages the relay. Grab that relay to and you could have as big of a light as you wanted :laugh3:

edit: this particular swich won't fit in the hole Eagle mentioned, but I'm sure you could find somthing that would. The 93 HO at least had one sensor on the t-stat housing for the computor, and one on the block for the guage/light. I know they switched it to one sensor only when they went to the next system (OBDII I belive). You would want the 90-X sensor from the block, "coolant temp switch", that would turn on a light at whatever temp the stock idiot light would come on. However I know the "radiator temp switch" in the Renix IS 220degrees

Thanks for the input guys. I think I'll combine the radiator temp switch with a tee fitting in the heater hose coming out of the tstat housing unless I or someone comes up with any more interesting ideas...... :lecture:

The radiator sender for the aux fan is a large diameter unit -- probably larger than the heater hose so it'll be difficult to tee it into the heater hose. But the standard idiot light sender for the Renix years is a smaller, standard pipe thread so you could make up a tee using 1/2" copper tubing and use that. Good idea, dunno why I didn't think of it except I'm accustomed to a sender in the block so my little brain defaulted to that.

i guess since you have you answers now i may as well throw my comments at ya. ahhh why do you want an idiot light when you have a guage, is it realy that far out of the way to look down at the guages. seems to me the only upgrade to the stock setup would be to put in an aftermarket guage and sender that may be more accurate. sorry just don't see the need for a guage then idioit light i mean that is what the guages are there for is to monitor your engine:wierd:

yes the radiator switch is large, you will need a T larger than standard 1/2" pipe thread.

:lecture:

bj-666 said:

i guess since you have you answers now i may as well throw my comments at ya. ahhh why do you want an idiot light when you have a guage, is it realy that far out of the way to look down at the guages. seems to me the only upgrade to the stock setup would be to put in an aftermarket guage and sender that may be more accurate. sorry just don't see the need for a guage then idioit light i mean that is what the guages are there for is to monitor your engine:wierd:

Click to expand...

If I still had my clutch fan setup I wouldn't worry about the idiot light. And I do check my gauges regularly. The potential problem with having only electric fans is that if, for some reason (blown fuse or something) they were to fail, the temp can rise within a matter of minutes and I could have a boil over situation before I know it. I would sure hate to do unneccesary damage to my new stroker. Ya know what I mean???.....!!!

Eagle, Slip Kid,

Thanks for the heads up about the size of the radiator temp switch.

just curious, how are you controlling your fans? are they all on continuous, or do you use a temp switch for one or two of them? or manual?

Its all preference, but if I had 3 elec fans, and wanted a 220 light, I'd hook up at least one fan to a relay - off the same temp switch the light uses. I would use 2 DPDT switches: up on, middle off, down auto for the 2 'aux' fans - and one regular switch for the 'main' fan. I'd use that 220 rad temp switch for the light and one of the 'auto's, then probably find a lower temp switch for the other 'auto' just for S's and G's. still curious about your fans, 3 elec is the only way I would ditch the clutch fan. did you have to cut or remove your grille?



oops I hijacked a thread :gag:

I have three 10" Perma Cool high performance electric fans side by side. According to their website(http://permacool.com/Catalog/Cat_page16.html ), they're each rated at 1250 cfm, so that makes a total of 3750 cfm at full blast.

For control, I'm using this from flex-a-lite(http://www.flex-a-lite.com/auto/html/vsc.html ). It works great. I like the soft start/stop and the automatic variable speed. It goes from 60% to 100% depending on demand.

I would post a picture of my fans and the brackets I made if I only knew how. I've tried before but I still can't get it right.

Oops. I forgot.

The only thing I had to remove were both stock fans and shrouds.

oooooh bling bling.

corbinafly said:

I have three 10" Perma Cool high performance electric fans side by side. According to their website(http://permacool.com/Catalog/Cat_page16.html ), they're each rated at 1250 cfm, so that makes a total of 3750 cfm at full blast.

For control, I'm using this from flex-a-lite(http://www.flex-a-lite.com/auto/html/vsc.html ). It works great. I like the soft start/stop and the automatic variable speed. It goes from 60% to 100% depending on demand.

I would post a picture of my fans and the brackets I made if I only knew how. I've tried before but I still can't get it right.

Click to expand...

I would love to see this. Let me know if I can help ya' get 'em posted.

Crawler said:

I would love to see this. Let me know if I can help ya' get 'em posted.

Click to expand...

Crawler,

I think I figured it out. I'll try to get some pics up after I get home from the job tomorrow.

Here's a pic of the fans connected together with some aluminum angle that I notched and drilled for install.



I'll take some pics tomorrow of the unit as it sits in the rig.