Running Hot

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Blitz
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Running Hot

#1

Post by Blitz » 12 Jul 2019, 12:26

I thought I might as well start a separate thread for this issue I'm having and see what ideas are out there! I know these issues have been talked about before, but figured I'd see what people thing of my situation.

My Cougar has been running hot, according to the TEMP gauge in the dash. Of course it doesn't give me an actual number, it's just a needle on a scale. But it'll get up there about 3/4 of the way up, sometimes more.

I have a 289-2V with A/C, and my factory 24" FoMoCo radiator and 7 blade clutch fan. I think it's actually a 3-core radiator since there's no empty space like you'd see with a 2-core. Anyway it must have been re-cored at some point because it's in good shape. 180 degree thermostat was installed at the time of the engine rebuild. It seems to work since the top hose gets very hot.

Chasing this issue, I took the radiator in to a radiator shop recently to see if it needed to be boiled out, if there was scale buildup. I also had one little leak at the top tank. The guy there (old cranky 74 year old who has been doing this forever) gave it a flush in both directions and there was just a little bit of dirty water that came out. He said it didn't need to be boiled and didn't want to waste my money. He patched the leak, and I touched up the paint and put it back in the car. The issue persists.

andrew project (1968)-1028.jpg
andrew project (1968)-1028.jpg (134.82 KiB) Viewed 265 times

Another thing I'm about to try is a different fan clutch. The one that WCCC has been selling (which I have on the car now) isn't the one that Hayden calls out for this application. Looking at it, it seems like the fan isn't far enough into the shroud. So I ordered one , and as soon as that arrives I'll be trying that, but I'm not sure if that's going to entirely solve the issue. Here's a view of where it's at now:

andrew project (1951)-1028.jpg
andrew project (1951)-1028.jpg (99.4 KiB) Viewed 265 times

I recently had a tune-up done and the timing is now set to 6° initial (factory spec) and 30-something total advance. It was also running hot when the timing was further advanced.

Running 50/50 distilled water and glycol with Water Wetter added. When I put the radiator back in, it drank a gallon of each plus a little extra. I thought the capacity was more than that, but I guess there was still coolant in the block. Anyway, still hot on the gauge.

I need to take an infrared thermometer reading and get back to you on what it says. What should I be looking for? Is the upper hose the ideal place to measure temp?

Is the default happy operating temperature supposed to be in the middle of the gauge like I'm used to seeing on other cars?

Does paint on the radiator fins make any difference? There's also the A/C condenser in front of the rad, and I painted it black as well. Wondering if that contributes enough to partially block airflow.

Also wondering if I should ditch the fan clutch entirely, use a spacer and run it directly. Not sure.

Open to your ideas!
-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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Royce
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Re: Running Hot

#2

Post by Royce » 12 Jul 2019, 12:48

The repro sending temp units have the incorrect resistance. They make the gage read too high. Get an original one and it normally fixes the problem.

If the radiator is 50 years old it might be that the tubes are all coated with corrosion on the inside. If so there is only one solution. New radiator.

The fan looks about right, should be 1/2 way into the shroud.
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
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desertdave55
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Re: Running Hot

#3

Post by desertdave55 » 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.

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Royce
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Re: Running Hot

#4

Post by Royce » 12 Jul 2019, 12:57

It should read about 195 -/+ degrees at mid gage.
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
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Royce
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Re: Running Hot

#5

Post by Royce » 12 Jul 2019, 12:59

Wow - off by more than 50% at 212 where you need to know! That says a lot.

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.
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
XR7-G Registrar

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propayne
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Re: Running Hot

#6

Post by propayne » 12 Jul 2019, 14:47

All I can add is when I was chasing some heat issues in my rebuilt 390 the biggest difference I got was when I replaced the run-of-the-mill re-popped fan clutch with a higher end (re more expensive) fan clutch that the Shelby guys recommended.

- Phillip

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Blitz
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Re: Running Hot

#7

Post by Blitz » 12 Jul 2019, 15:16

All very interesting ideas! I'll see if I can get an original temp sender. I drove the car at lunch just now and after getting back I kept it running and got out the cheapo laser temperature reader. Was getting readings that seem fairly normal, ranging from around 180-200 on things like the upper rad hose, top tank, and the temp sender itself.
propayne wrote:
12 Jul 2019, 14:47
All I can add is when I was chasing some heat issues in my rebuilt 390 the biggest difference I got was when I replaced the run-of-the-mill re-popped fan clutch with a higher end (re more expensive) fan clutch that the Shelby guys recommended.
Do you remember what it was? I know Hayden makes various grades of clutches, but they don't have a heavy duty one listed for my application. Just the basic one.
-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

ccarney69
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Re: Running Hot

#8

Post by ccarney69 » 12 Jul 2019, 15:41

I had the same issue with an aftermarket temp sending unit. After installing it I was reading up near the hotline. I took it out and put an original back in and was back to the mid range.
1968 GT-E 427 Standard
1968 Two Tone Standard 302
1969 XR7 428 CJ Q Code
1969 XR7 428 CJ R Code

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catlover
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Re: Running Hot

#9

Post by catlover » 12 Jul 2019, 15:54

Phillip, I too would like to know which clutch you used because I have not found one that did the job.
Instead of locking up when hot, they got much looser.
There is never time to do it right, but always time to do it over

67 Cougar restomod
69 Elim. 428 SCJ orange/ white
CCOA 7574

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Blitz
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Re: Running Hot

#10

Post by Blitz » 12 Jul 2019, 16:24

catlover wrote:
12 Jul 2019, 15:54
Phillip, I too would like to know which clutch you used because I have not found one that did the job.
Instead of locking up when hot, they got much looser.
From what I've gathered, they never really lock up all the way. But you'd think it would get tighter! On Hayden's website they describe the different levels of clutches they have:

Standard Duty
Turns fan 60-70% of shaft speed when engaged
Disengage to 20-30% of the shaft speed
Used with lighter pitch fans (1-1/2” of pitch)
Flat plate impeller design with up to 11.4 sq. in. of working surface
Identified by a smooth steel faceplate & thermal spring assembly on the front side

Heavy Duty
Turns the fan 70-90% of the shaft speed when engaged for increased cooling
Turns the fan 25-35% of the shaft speed when disengaged
Used with deeper pitch fans (2-1/2” of pitch)
Land and groove design with up to 27 sq. in. of working surface
Identified by finned aluminum faceplate and thermal spring on the front

Severe Duty
Turns the fan 80-90% of the shaft speed when engaged
Turns the fan 20-30% of the shaft speed when disengaged
Used with deeper pitch fans (2-1/2” of pitch)
Land and groove design with up to 72 sq. in. of working area
Larger working surface provides cooler running and longer life expectancy
Thicker body and deep finned faceplate dissipates more heat
Can be used in place of many heavy-duty clutches

Their part # 2710 is the only thermal clutch they offer for a '68 Cougar and it's Standard Duty. Since it only gets about 70% of the shaft speed, this is why I was thinking of converting it to a fixed mount. But I will try the 2710. Right now I have a 2711 on it for some reason. Did WCCC's former purchasing agent make a typo? Hmmm
-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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