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  •  » Radiators and relays.

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    2/24/2023 1:47 PM  #1

    boss347convertible
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    Registered: 4/22/2013
    Posts: 157

    Radiators and relays.

    Two or three years ago, my four row aluminum Champion radiator developed a pinhole leak. I have dual Spal fans and decided to try a Champion 3 row radiator. Both radiators are 24 inches wide, and the car has not overheated with either radiator. About 2 weeks ago, I drove the Mustang approximately 500 miles round trip from SoCal to San Luis Obispo and traffic through Los Angeles was at a slow standstill for about an hour. Ambient temperature was about 80F. The temperature gauge was creeping up the "P" and I could hear what I thought were the fans working. 

    Getting out of LA traffic, the temperature gauge returned to its normal position and did not waiver. Last night, while working on the car, I noticed only one fan was working. Testing traced back to the cheap foreign relay that I put in about a year ago. I put in a Bosch relay, which typically lasts a couple of years in this application. The high load and constant switching on and off, tends to destroy these relays. In the past, while traveling, I have used a paper clip to bypass a failed relay and the paper clip became too hot to touch.
    I will look for a quality relay and put it in the trunk.
     

     

    2/24/2023 4:05 PM  #2

    Rufus68
    I FYI 24-7

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    From: Knoxville, TN
    Registered: 4/26/2017
    Posts: 889

    Re: Radiators and relays.

    Perhaps you should also increase the wire gauge feeding those fans.  This might actually help the circuit be cooler and less stressful to the relays.

    1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
     

    2/24/2023 5:18 PM  #3

    boss347convertible
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    Re: Radiators and relays.

    Rufus68 wrote:

    Perhaps you should also increase the wire gauge feeding those fans.  This might actually help the circuit be cooler and less stressful to the relays.

    A good observation. Because the fans draw so much amperage, I ran a battery cable (trunk mounted battery) to a post terminal within a foot of the fans and shortened the run of the Spal factory wiring. I used Spal's relay kit (two of these:  https://www.spalusa.com/products/fans/fan_accessories/fan-relay-harness-frh ) and am satisfied that the Spal factory wiring is sufficient. Could be wrong, but the wiring has not been hot to the touch and no melted wire insulation.
     

       •Thread Starter
     

    2/24/2023 6:08 PM  #4

    Rufus68
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    From: Knoxville, TN
    Registered: 4/26/2017
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    Re: Radiators and relays.

    boss347convertible wrote:

    Rufus68 wrote:

    Perhaps you should also increase the wire gauge feeding those fans.  This might actually help the circuit be cooler and less stressful to the relays.

    A good observation. Because the fans draw so much amperage, I ran a battery cable (trunk mounted battery) to a post terminal within a foot of the fans and shortened the run of the Spal factory wiring. I used Spal's relay kit (two of these:  https://www.spalusa.com/products/fans/fan_accessories/fan-relay-harness-frh ) and am satisfied that the Spal factory wiring is sufficient. Could be wrong, but the wiring has not been hot to the touch and no melted wire insulation.
     

    Definitely sounds like you have it set up nicely.
     

    1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
     

    2/24/2023 6:11 PM  #5

    Rufus68
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    From: Knoxville, TN
    Registered: 4/26/2017
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    Re: Radiators and relays.

    What about switching to this type of continuous duty relay?

    https://www.amazon.com/IRHAPSODY-120Amp-Continuous-Terminal-Starter/dp/B07T35K8S2/ref=sr_1_3?keywords=heavy%2Bduty%2Brelays&link_code=qs&qid=1677283779&sourceid=Mozilla-search&sr=8-3&th=1

    1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
     

    2/25/2023 7:22 AM  #6

    TKOPerformance
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    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,486

    Re: Radiators and relays.

    On start the instantaneous load on my fan is enough to flow a 30amp fuse.  A 40 allows the system to operate without issue.  I have 10 gauge wire on the high amp side of that circuit.  I run a single fan, but also a SPAL. 

     

    2/25/2023 1:19 PM  #7

    boss347convertible
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    Registered: 4/22/2013
    Posts: 157

    Re: Radiators and relays.

    Rufus68 wrote:

    What about switching to this type of continuous duty relay?

    https://www.amazon.com/IRHAPSODY-120Amp-Continuous-Terminal-Starter/dp/B07T35K8S2/ref=sr_1_3?keywords=heavy%2Bduty%2Brelays&link_code=qs&qid=1677283779&sourceid=Mozilla-search&sr=8-3&th=1

    That would work, but I don't want to get into a rewire at this time. Easier for me to pop in a new relay every 5 years or so.

       •Thread Starter
     

    2/25/2023 1:38 PM  #8

    boss347convertible
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    Re: Radiators and relays.

    TKOPerformance wrote:

    On start the instantaneous load on my fan is enough to flow a 30amp fuse.  A 40 allows the system to operate without issue.  I have 10 gauge wire on the high amp side of that circuit.  I run a single fan, but also a SPAL. 

    I have two 12 inch fans, each on its own circuit fused at 25 amps each, and each with its own 30 amp relay. Over the last 16 years, no blown fuse, but I have replaced the relays two or three times. My recollection is that the service life on the Bosch relays was much longer than the cheap relays, so I have gone back to Bosch relays. 

    My buddy is a Volvo mechanic and he has a dozen late model Volvo fans (Spal) with shrouds stacked at his shop. The fans work, but the controller fails, requiring complete replacement of the fans and controller. The Volvo fans are a great setup, one small fan and one large fan. My guess is the controller fails due to the high start up load. If my fans fail, I will install the Volvo fans using my existing wiring. I know there are some "soft start" fan controllers available, but I don't have any information on the controllers' reliability/durability.
     

    Last edited by boss347convertible (2/25/2023 1:39 PM)

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    2/25/2023 1:38 PM  #9

    6sally6
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    From: Surfside Beach,SC
    Registered: 4/02/2013
    Posts: 6,849

    Re: Radiators and relays.

    boss347convertible wrote:

    Rufus68 wrote:

    What about switching to this type of continuous duty relay?

    https://www.amazon.com/IRHAPSODY-120Amp-Continuous-Terminal-Starter/dp/B07T35K8S2/ref=sr_1_3?keywords=heavy%2Bduty%2Brelays&link_code=qs&qid=1677283779&sourceid=Mozilla-search&sr=8-3&th=1

    . Easier for me to pop in a new relay every 5 years or so.

    OR.......just stay outta LA !!
    6sal6
     

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    2/25/2023 1:56 PM  #10

    boss347convertible
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    Registered: 4/22/2013
    Posts: 157

    Re: Radiators and relays.

    6sally6 wrote:

    boss347convertible wrote:

    Rufus68 wrote:

    What about switching to this type of continuous duty relay?

    https://www.amazon.com/IRHAPSODY-120Amp-Continuous-Terminal-Starter/dp/B07T35K8S2/ref=sr_1_3?keywords=heavy%2Bduty%2Brelays&link_code=qs&qid=1677283779&sourceid=Mozilla-search&sr=8-3&th=1

    . Easier for me to pop in a new relay every 5 years or so.

    OR.......just stay outta LA !!
    6sal6
    That would be great, but for all points north, whether by Model T or Mustang, I have to pass through LA, preferably via Highway 1, but when time is of the essence, via 405. LA was a great county at one time: chrome shops all over, paint booths you could rent for a day, speed shops within a mile of anywhere, drag strips, dirt tracks, abandoned airports for auto-crossing, mx tracks, dirt bike trails and more. Now, virtually nothing. I am including Orange County in the foregoing.

    I'm not complaining, tomorrow I will be driving the 66 in the sun with the top down.
     

     

       •Thread Starter
     

    2/27/2023 6:12 AM  #11

    Nos681
    Senior 24-7 FYI Addict

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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,326

    Re: Radiators and relays.

    I would look into the soft start relay found in a Lexus or Nissan.

    I watched a very good YouTube video about it recently.
    I have no idea at the moment who it was.

    It ramps up the fan speed and he also used a variable speed controller to adjust duty cycle %.

    If I find it, I will share it.

     

     

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