Notices
964 Forum
Sponsored by:
Sponsored by:

How to turn in oil cooler fan by 212F?

 
Old 06-20-2011, 05:54 AM
  #1  
rollingjack
User
Thread Starter
 
rollingjack's Avatar
 
Join Date: Nov 2006
Location: Estland
Posts: 70
Default How to turn in oil cooler fan by 212F?

I started to study this a little, because was full week with temperatures 86F and up.

First I measured with IR thermometer and ohmmeter, which resistance has NTC sensor (sensor by oil cooler) by 212F (100C).
That was my goal for turn on first speed of oil cooler fan. I got reading about 1009 ohm.

Now I putted in NTC plug rheostat instead NTC sensor. By changing resistance I find points where CCU turn in first and second speed for fan. I got readings 696 ohm for first speed and 591 ohm for second speed of fan.

Then I measured, when fan first kicks in. It was by 230F (110C)

So, how to do, to got from NTC sensor resistance 696 ohm by 212F?

As we know, to add some resistor increases resistance. Not in all time. If we put resistors parallel, then we can reduce resistance sometimes:

1/R1 +1/R2 =1/Rtotal

I wrote in one MS exel worksheet in box A1 "=1/1009+1/x" and in next box B1 "=1/A1". I putted then instead "x" different readings and goal was in B1 to get reading 696. To closest "x" was 2200. OK, this exel is only for example, you can calculate it of coarse in better way.

It means, that I must add resistor 2,2 kohm parallel to NTC sensor, to get resistance 696 ohm by 212F.
I find one 2,2 kohm resistor for 0,6W. It is enough, because current here is very small. And this resistor is small, about 0,24 inch long. I choose metal film resistor, not carbon. Metal film resistor is more durable for vibration.

Good place to put resistor was in plug by NTC sensor. Turned rubber protection by plug back, I got access to wires. Cleaned wires little from isolation, then I soldered my resistor between two wires in plug. Rubber protection back and you see no difference with foregoing.

It works! Fan is turning now on by 212F and out by 196F.

Material cost was only 5 eurocent.
rollingjack is offline  
Old 06-20-2011, 09:05 AM
  #2  
KaiB
Banned
 
Join Date: Feb 2011
Location: Deep Downtown Carrier, OK
Posts: 5,297
Default

Good work!
KaiB is offline  
Old 06-20-2011, 10:56 AM
  #3  
Steve Weiner-Rennsport Systems
RL Technical Advisor
 
Steve Weiner-Rennsport Systems's Avatar
 
Join Date: May 2001
Location: Portland Oregon
Posts: 11,836
Default

Very well done!!!

This will be quite useful for many people on here since the factory setup turns the fan on too late to properly control oil temps on hot days.
Steve Weiner-Rennsport Systems is offline  
Old 06-20-2011, 01:55 PM
  #4  
jimq
Burgled
Rennlist Member
 
jimq's Avatar
 
Join Date: Aug 2003
Location: Altamonte Springs, Fl/Gwynns Island, Va.
Posts: 22,348
Default

Did you take any pictures of how you put it in the plug?
That would be a handy mod in the Florida heat.
jimq is offline  
Old 06-20-2011, 04:49 PM
  #5  
rollingjack
User
Thread Starter
 
rollingjack's Avatar
 
Join Date: Nov 2006
Location: Estland
Posts: 70
Default

many thanks - KaiB and Steve.

jimq- here is picture of my setup-little tricky work (resistor is so small) in NTC sensor plug under front right fender, but doable:

rollingjack is offline  
Old 07-11-2011, 04:23 PM
  #6  
Vandit
Super User
 
Join Date: Jul 2007
Location: DFW, TX
Posts: 5,458
Default

Do you have a link where I could get the appropriate resistor stateside?

I checked Radioshack's website and it doesn't seem like they have a 6w in 2.2k ohm resistors, unless I'm looking at them wrong (very possible).

http://www.radioshack.com/search/ind...=2.2k+ohm&sr=1
Vandit is offline  
Old 07-11-2011, 04:32 PM
  #7  
Laker
Super User
 
Laker's Avatar
 
Join Date: Sep 2010
Location: Philly 'burbs
Posts: 2,568
Default

rolling jack found one that was 0.6 watt, and it's low wattage application, so ...Radio shack's 0.5 watt... should do.
Laker is offline  
Old 07-11-2011, 05:59 PM
  #8  
ja78911sc
User
 
ja78911sc's Avatar
 
Join Date: Nov 2010
Location: Omaha, NE
Posts: 652
Default

Nice work !

How did this mod effect your fan high speed setting (second speed) ?

Your new low speed fan starting point is at 212 and ending at 196. If your temps continue to rise above 212, will the low speed setting be the only functioning fan speed ?

Thanks,
Jim
ja78911sc is offline  
Old 07-11-2011, 11:30 PM
  #9  
Vandit
Super User
 
Join Date: Jul 2007
Location: DFW, TX
Posts: 5,458
Default

Originally Posted by rollingjack View Post
many thanks - KaiB and Steve.

jimq- here is picture of my setup-little tricky work (resistor is so small) in NTC sensor plug under front right fender, but doable:

Is this plug the same plug visible in this pic?


Between where the oil lines go into the cooler.
Vandit is offline  
Old 07-12-2011, 03:51 AM
  #10  
rollingjack
User
Thread Starter
 
rollingjack's Avatar
 
Join Date: Nov 2006
Location: Estland
Posts: 70
Default

Originally Posted by ja78911sc View Post
Nice work !

How did this mod effect your fan high speed setting (second speed) ?

Your new low speed fan starting point is at 212 and ending at 196. If your temps continue to rise above 212, will the low speed setting be the only functioning fan speed ?

Thanks,
Jim
Thanks Jim,
High speed for fan turn in, if oil temperature rises to 221F.
This is same setting as before, but turn in points for oil cooler fan are by lower temperature.
CCU get same readings for resistance as before, but temperature by oil cooler is lower.
rollingjack is offline  
Old 07-12-2011, 03:57 AM
  #11  
rollingjack
User
Thread Starter
 
rollingjack's Avatar
 
Join Date: Nov 2006
Location: Estland
Posts: 70
Default

Vandit-
there is no difference in Watt, you can use 0,5W or 5W resistors. More important are dimensions- if it is big, you have problem to put it between wires in plug.


About pictures- yes, right- this is plug by NTC sensor, located by oil cooler.
rollingjack is offline  
Old 07-12-2011, 11:06 AM
  #12  
ja78911sc
User
 
ja78911sc's Avatar
 
Join Date: Nov 2010
Location: Omaha, NE
Posts: 652
Default

Originally Posted by rollingjack View Post
Thanks Jim,
High speed for fan turn in, if oil temperature rises to 221F.
This is same setting as before, but turn in points for oil cooler fan are by lower temperature.
CCU get same readings for resistance as before, but temperature by oil cooler is lower.
So the change in resistance effected the low & high speed fan--nice work. High is now operating around 221 vs. the factory setting at 240+.

Question on the resistor:

Does it make a difference which wire from the resistor you attach to the sensor wire? (Basically, If you changed the direction of the resistor in your photo, would it still work)

Thanks,
Jim
ja78911sc is offline  
Old 07-12-2011, 01:00 PM
  #13  
cjoenck
Addict
Rennlist Member
 
Join Date: Dec 2007
Location: Chicago, IL
Posts: 287
Default

Resistors are direction independent. Unlike a diode, you can use a resistor either way.

This is a clever mod. You just "fool" the CCU by changing the resistance of the sensor by a fixed amount.

Nice.
cjoenck is offline  
Old 07-12-2011, 03:24 PM
  #14  
rollingjack
User
Thread Starter
 
rollingjack's Avatar
 
Join Date: Nov 2006
Location: Estland
Posts: 70
Default

Originally Posted by cjoenck View Post
Resistors are direction independent. Unlike a diode, you can use a resistor either way.

This is a clever mod. You just "fool" the CCU by changing the resistance of the sensor by a fixed amount.

Nice.
+1
rollingjack is offline  
Old 08-14-2011, 06:02 PM
  #15  
Laker
Super User
 
Laker's Avatar
 
Join Date: Sep 2010
Location: Philly 'burbs
Posts: 2,568
Default

Thanks Rollingjack for the idea, pictures and crunching numbers to come up with the correct resistance!

Did the mod today since I was in there anyway for the low tone horn.
Five resistors for $1.20 The first four people that PM with their mailing address can have one.

Remove front right wheel
Remove front mud guard.

The temperature sensor is at the top of the resistor 5-pack.
with two small flat bladed screwdrivers, carefully peel back the boot over the sensor connector.
Take your time, because it's 20 years old and a little brittle.


Nicked a wire to remove insulation on 3 sides without breaking any of the copper strands.

wrapped a resistor lead around the exposed wire.

Wrapped up the exposed solder and part of the resistor with some tape, then nicked the other lead about 1cm higher as I want the resistor to run parallel to the leads so the boot would fit over two leads and a resistor.
Taped it all up , then rolled back the boot over the leads, resistor and it fit nice and snugly.

It's pouring rain today, so will have to test later and post results.

Edit: having issues with linking photos... here is a direct link to the album
https://rennlist.com/forums/members/...istor-mod.html and adding as attachments
Attached Images       

Last edited by Laker; 08-14-2011 at 11:18 PM.
Laker is offline  

Thread Tools
Search this Thread
Quick Reply: How to turn in oil cooler fan by 212F?


Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: