axl911

Just had this idea popped into my head. Tell me what you think.

Instead of just splicing a switch to activate the oil cooler fan, why don't we use rheostat (adjustable resistance). The fan would come on if the resistance reaches a certain value. By adjusting the rheostat, you can get the fan to come on at a lower temperature. Or have it full open to manually turn the fan on.

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anthony

jimbo3

Myabe I don't understand what you have in mind, but a rheostat in place of an on/off switch would only operate the speed of the fan. I, too, would like to have the fan turn on a little cooler than 230 (or whatever the exact temp is). It can get HOT here in South Texas!

NP993

Have you seen this idea?

http://forums.pelicanparts.com/showthread.php?t=360728

Mike J

Funny, I was just thinking of trying to find another sensor that has a lower threshold and **viola** a posting comes out with a neat thread! Thanks!

Cheers,

Mike

axl911

The wire which we slice to make the oil cooler manual switch goes to the temperature probe. It doesn't control the speed of the fan. The Resistor control the speeds of the fan. As I understand it, the resistance of the probe varies inversely with the temperature. So using the rheostat, you can increase the resistance seen and tricking the computer to thinking the temperature is hotter. Thereby, triggering the fan to come on earlier.

jimbo3

Looks like the warmest Spal unit turns on at 185F and off a 176F. Way too cold and the fan would run too much. I would think that about 210/195 would be better. Ideally, I'd want the high speed to kick in around 220 to 225, too. Kinda wonder what those crazy Germans were thinking with the warmer temps...

NP993

Why? I never want my car running at 220+. 180 to 200 is ideal. Anything more and engine wear increases rapidly.

jimbo3

The factory already set your engine to regularily run at 230 degrees! Changing that is what this thread is about.

There's a high speed and a low speed for the fan. The low speed kicks on first and at a lower temp than the high speed. You may have missed the previous sentence in my post where I suggested that the low speed keep the engine around 200 degrees. Since the high speed can't (or shouldn't) kick in a the same time, it would seem logical that it would kick in at 10 to 15 degrees warmer than the low speed temp.

Heck, I'm still trying to figure out why the P engineers set the low speed fan at around 230 and the high speed even higher than that. FWIW, I doubt that the high speed has ever kicked in on my car.

jimbo3

Wouldn't it be easier/cleaner to solder in a resistor to the probe lead? All we'd have to do would be to figure out the correct resistor values for two or three target temps and then choose the temp you desire and install. If I were just a little smarter, I might be able to figure all of this out, but I've never been accused of being terribly bright....

-Jim

axl911

I was also thinking of the same thing.

brucec59

Is the temp sensor is a thermo-switch or a thermo-resistor? If it is a switch (opens at X degrees), a the resistor idea will not work.

North Coast Cab

Did this project die? Sure would like to just change the sender and be done with it.

Marlon

What a 'cool' idea with the wires-from-the-fuze-box to a switch! However, my engine oil cooler fan still will not come on automatically even afer replacing the ballast resistor, replaced oil temp sensor and checking the fuze. It Does come on Hi if I unplug the temp sensor though. Not sure the 'switched' fuze would work for me with my symptoms.

North Coast Cab

This was a cool idea and if you stuck to the original thread idea and the lead to another thread on Pelican about a lower temp sender you would understand.

Marlon

...the pelican 'brief' was very informative...