Electric fan conversion temp. question

Insubordination

Apprentice

Jan 13, 2012

72

1

8

Norway

• Sep 8, 2012

• #1

I've been thinking on this for some time, but my limited knowledge has me stumped.

I'm converting to electrical fans. And I want them to start automaticly at a given temperature. My thermostat in my Olds 350 engine opens at 195 F (91C). A stock thermostat in accordance with the service manual.

So what I'm wondering about is at what temperature should my fans kick in / what temp unit to get?

I have one lying around for 200 F (93,3 C), but that seems a bit to soon.

Anyone?

 

odaci0us

Not-quite-so-new-guy

Aug 1, 2012

7

0

0

40

Citronelle, Alabama

• Sep 9, 2012

• #2

I'm pretty sure they should shut off at 5 degrees after your thermostat opens.

 

H

H2O gbodies

Apprentice

May 2, 2009

96

6

8

• Sep 9, 2012

• #3

Remember too that the thermostat gradually open until at 195 then its fully open so you still have some circulation. I would go with a 212-202 temp switch so its rated just above your t-stat rating. This way, you get some circulation through the system at moderate and higher speeds where airflow should be sufficient enough to keep engine cool without the fan kicking on. If you have the fans come on too early, you never really give your cooling system a chance to shed heat first before a fan is even needed to kick on.

It's this reason why I think most people choose too early of a fan turn on. You want the off temp to be just slightly higher than the t stat open rating. Hope that clears some questions up.

 

L92 OLDS

Comic Book Super Hero

Mar 30, 2012

2,872

3,059

113

58

West Michigan

www.youtube.com

• Sep 9, 2012

• #4

Where is a good place to get temperature sending units? I'm a cheap bastage and don't want to pay Summit $35-$40 for one. Anyone know of a good source?

 

Insubordination

Apprentice

Jan 13, 2012

72

1

8

Norway

• Sep 10, 2012

• #5

Anubis said:

Where is a good place to get temperature sending units? I'm a cheap bastage and don't want to pay Summit $35-$40 for one. Anyone know of a good source?

Click to expand...

I second the cheap bastage stance for myself as well. And good question.

 

DRIVEN

Geezer

Apr 25, 2009

8,218

15,262

113

*CENSORED*

• Sep 10, 2012

• #6

My research indicates that an OE Grand National fan switch (3053190) is on at 210* and off at 200*. These were the crossover numbers according to the interwebz. Hope it helps:
AC Delco 15-4229
B/W TFS1
STD TS-147
Niehoff DR137S
Echlin FS110

 

84cutspreme

Royal Smart Person

Jun 4, 2009

1,163

158

63

• Sep 10, 2012

• #7

I just installed new dual electric fans, the company I used recommended using a 160 T-stat. Fan sending unit turns fans on @ 195 and off @ 175. They say that 160 will run cool enough so fans are not running all the time

 

80ELCAMINOFLAKE

Comic Book Super Hero

Sep 2, 2010

2,685

14

38

California So Cal

• Sep 10, 2012

• #8

84cutspreme said:

I just installed new dual electric fans, the company I used recommended using a 160 T-stat. Fan sending unit turns fans on @ 195 and off @ 175. They say that 160 will run cool enough so fans are not running all the time

Click to expand...

Im thinking of running a 160 t stat in my water neck as well, have u test drove it to see if it stats freash?

 

H

H2O gbodies

Apprentice

May 2, 2009

96

6

8

• Sep 10, 2012

• #9

I would not suggest running a 160 t-stat....you will get a much better and more complete fuel atomization if you run between 190-200. If you run too cool you'll use way more fuel and it'll build up a lot more carbon deposits. Running an engine too cool is not a good thing.

 

bill

Royal Smart Person

Jul 11, 2008

2,332

11

38

60

southside va/lake gaston

• Sep 10, 2012

• #10

From what I have learned and have been told, Olds motors like to run at 195-210 degrees, depending on the season. Any t-stat that opens at 160 or even 180, would keep the engine too cool and not at optimum performance temp. After my lastest fiasco with my electric fan, I see no benefit to pulling off the manual fan and hope and pray the electric fan/relay doesnt burn up! If you do go with an electric fan, dont use a 30 amp relay...use at least a 40 amp one. I believe that is why mine burned up. good luck!