Running Hot

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propayne
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Re: Running Hot

#11

Post by propayne » 12 Jul 2019, 18:06

I got it from Chris Brown -

http://www.brownsautobodyservices.com/shop

I heard someone say at a car show that maybe it is a Jaguar part?

- Phillip

PacificaXR7GT
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Re: Running Hot

#12

Post by PacificaXR7GT » 12 Jul 2019, 18:35

I’m hoping this sender will give me a more accurate read on my 390. I’ll let you know if it works.

https://www.ebay.com/itm/66-67-68-Musta ... SwuN9cj6yB
Steve
CCOA #9998
1968 XR7 GT 4 speed - Augusta Green / Dark Ivy Gold


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Midlife
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Re: Running Hot

#13

Post by Midlife » 12 Jul 2019, 18:58

desertdave55 wrote:
12 Jul 2019, 12:53
A few years back someone documented aftermarket vs FoMoCo temp sending units. The first value is aftermarket, while the second is the NOS temp sender he measured.
Temp-----Ohms-----Ohms
100*F----197--------197
110*F----150--------145
120*F----135--------120
130*F-----------------90
140*F----70----------71
150*F-----------------67
160*F----46----------47
170*F----35----------34
180*F----26----------27
190*F----20----------19
200*F----15----------14
212*F----2------------5

Obviously you'll need an infrared to compare to, but in the meantime it'd be interesting to see where your high and low values lie.
Those measurements are not for the vintage sending units we all know and love, but are from the mid-70's on up. Our sending units run from 13 to 73 ohms, full scale.

Do not believe these numbers, they are not correct at all, not even close!

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Blitz
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Re: Running Hot

#14

Post by Blitz » 15 Jul 2019, 10:44

The plot thickens. I found an original Autolite sending unit but it didn't seem to work. I got no reading on the gauge. Then when I went to pull the wire / elbow connector back off, it broke. So now I get to splice on another elbow plug.

Any experience with the Motorcraft unit that's still available new? Surely it must be more accurate than the generic repro?

https://www.summitracing.com/parts/mof- ... gLFkvD_BwE

Anyway I think changing the fan clutch helped, but don't have data yet to confirm.
-Andrew Chenovick
Photo/Video guy for WEST COAST CLASSIC COUGAR, INC.
Side Gig: FLYING A PHOTOGRAPHY


RIDES:
-1968 Mercury Cougar: original family owned, Polar White, 289-2V, auto, AC / "Snowball" view project thread
-1973 Opel Manta: 1.9L, 5-speed (restored)
-1991 Mazda Miata: fun driver
-1992 Volvo 240 wagon: classy hauling machine

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xr7g428
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Re: Running Hot

#15

Post by xr7g428 » 16 Jul 2019, 09:27

To understand a heating issue you have to be specific about when it over heats. On the highway, the fan and fan clutch are irrelevant. The ram air effect is putting more air through the radiator than any fan you can fit. If it over heats on the highway, you know that you are getting enough air. In that case you focus on heat transfer. The heat is carried out of the engine by the coolant. Coolant flow is most often limited by the thermostat opening size, or obstructions in the radiator. Keep in mind that power equals heat, so on the highway your are making more power and more heat. The highway is the big test. If it gets hot at traffic lights or putting around town and then cools down on the highway you are not getting enough air. This is where you look at the fan shroud fan clutch, most commonly the fan clutch isn't locking up.
Bill Basore, Editor / Publisher
Legendary Cougar Magazine
Currently in the Cat House
'67 XR7 GT 390 4 speed, AC, AM FM, Lime Frost Green
'68 XR7-G 428CJ C6, Tilt-Away, AM, Black Cherry
'68 XR7-G 390 4 speed, Sunroof, Cardinal Red
'68 XR7 GT-E 427 C6 AM Cardinal Red
'68 XR7 resto mod 351W, soon to be AOD, Black Cherry

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Blitz
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Re: Running Hot

#16

Post by Blitz » 16 Jul 2019, 10:05

Good thoughts Bill. I was wondering about the thermostat. I looked back at receipts and I just used a standard 180 degree one. And I assume I put it in the correct way...
Radiator wasn't plugged so I don't think that's it, but I wonder about the block. I'm not sure if the machine shop did anything to flush out water passages when it was getting rebuilt.
Anyway, my suspicion now is that it's actually okay. I just need to find a sending unit that will give me an accurate reading. I just tried a used Motorcraft one I found here at the shop and it read pretty far down on the Cold side even when at full operating temp. Argh.
-Andrew Chenovick
Photo/Video guy for WEST COAST CLASSIC COUGAR, INC.
Side Gig: FLYING A PHOTOGRAPHY


RIDES:
-1968 Mercury Cougar: original family owned, Polar White, 289-2V, auto, AC / "Snowball" view project thread
-1973 Opel Manta: 1.9L, 5-speed (restored)
-1991 Mazda Miata: fun driver
-1992 Volvo 240 wagon: classy hauling machine

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70b302cat
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Re: Running Hot

#17

Post by 70b302cat » 16 Jul 2019, 12:03

I don't know how much difference there are in calibrations, but according to my MPC the sender you posted at Summit is not correct for your car. I show the following from my MPC (April 1973). This also might help in your search of the used ones at WCCC.

67 to 69 all except (69 351) use a C6DZ 10884-B (SW-552)
69 351 use a C9WY 10884-A (SW-888)
70 302 HO & 428 & 71 429 use the one that you posted D0ZZ10884-A (SW -925)
70 351 use a D0WY 10884-A (SW-924)

I don't have obsolete superseeded books to determine if SW-552 was updated at some point.
Dave

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70 Convertible 351C 4V Close ratio
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JETEXAS
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Re: Running Hot

#18

Post by JETEXAS » 16 Jul 2019, 12:26

Did you put a new water pump on the engine when you rebuilt it or just use the same one? The impeller fins corrode and disappear over time.

My cooling system was in really bad shape when I got my car, so after multiple flushes, I ran a garden hose through it for several minutes before the water stopped coming out rusty and came out clean. If you're shedding rust into the water, it's going to thicken up and not transfer heat so well. Might try flushing with Thermocure Evap-o-rust.

I have a temp sender from your shop, and it reads about 1/4 from the left when I'm at 180 -- doesn't even get to the T in TEMP.
1967 Standard, 302 with AOD

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xr7g428
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Re: Running Hot

#19

Post by xr7g428 » 16 Jul 2019, 12:39

For the technically minded. Buy a good quality 5 watt 100 ohm linear potentiometer. (variable resistor). Use a good aligator clip lead to ground one side to the block and then another clip lead to the end of the gauge wire. Adjust the potentiometer until the gauge is reading mid scale. Be patient, as the instrument voltage regulator is pulsing at around 5 volts and the gauge needs time to settle. Once you see the reading you want, disconnect the pot and read the resistance. This now shows the value you want to see from the sender. You may wnat to take readings for several places across the scale.

Next, see what the sender is really doing. Put clip leads attached to your meter on each end of the sender, and then drop the sender in a pan full of water on the kitchen stove. Use a candy thermometer to read water temp. Take note of the resistance at different temps up to boiling at 212 degrees.

Now combine the data to understand what is really happening.
Bill Basore, Editor / Publisher
Legendary Cougar Magazine
Currently in the Cat House
'67 XR7 GT 390 4 speed, AC, AM FM, Lime Frost Green
'68 XR7-G 428CJ C6, Tilt-Away, AM, Black Cherry
'68 XR7-G 390 4 speed, Sunroof, Cardinal Red
'68 XR7 GT-E 427 C6 AM Cardinal Red
'68 XR7 resto mod 351W, soon to be AOD, Black Cherry

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Blitz
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Re: Running Hot

#20

Post by Blitz » 16 Jul 2019, 12:54

70b302cat wrote:
16 Jul 2019, 12:03
I don't know how much difference there are in calibrations, but according to my MPC the sender you posted at Summit is not correct for your car. I show the following from my MPC (April 1973). This also might help in your search of the used ones at WCCC.

67 to 69 all except (69 351) use a C6DZ 10884-B (SW-552)
Thanks for the info. You may be right, I tested another used one today that was marked Motorcraft and had some remnants of red sealant on the threads. After driving the car and getting it up to full operating temp, the gauge was still just barely above the "C". So that's a no-go.
JETEXAS wrote:
16 Jul 2019, 12:26
Did you put a new water pump on the engine when you rebuilt it or just use the same one? The impeller fins corrode and disappear over time.

I have a temp sender from your shop, and it reads about 1/4 from the left when I'm at 180 -- doesn't even get to the T in TEMP.
Yup it's a new water pump. And that's interesting, sounds like you have the opposite problem with the aftermarket sender.
-Andrew Chenovick
Photo/Video guy for WEST COAST CLASSIC COUGAR, INC.
Side Gig: FLYING A PHOTOGRAPHY


RIDES:
-1968 Mercury Cougar: original family owned, Polar White, 289-2V, auto, AC / "Snowball" view project thread
-1973 Opel Manta: 1.9L, 5-speed (restored)
-1991 Mazda Miata: fun driver
-1992 Volvo 240 wagon: classy hauling machine

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