Author Topic: Odd 426 crate Hemi problem, no heat  (Read 836 times)

Offline 734406pk

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Re: Odd 426 crate Hemi problem, no heat
« Reply #15 on: July 02, 2017 - 02:49:35 pm »
Yeah, but with a 180 thermostat the fan can be blowing all the air it wants, the engine should warm up to 180..... I'd try another thermostat....  :2cents:

This is true! The engine temp should be regulated by the thermostat. The t-stat should open and close based on its set point, regulating coolant temp to 180 deg in this case. This could be a far fetched idea; but the engine also radiates heat to the atmosphere from it's own surface area, independent from the liquid cooling system. Air flow from a stuck thermo clutch increases the heat rejection to atmosphere to some point, possibly lowering the coolant temp at light load below the thermostat opening set point. I have had this happen on a few vehicles, but they were definitely not Hemi Cudas. Just a crazy idea in the process of elimination. :thinkerg:
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive




Offline gyman98

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Re: Odd 426 crate Hemi problem, no heat
« Reply #16 on: July 02, 2017 - 04:16:42 pm »
Yeah, but with a 180 thermostat the fan can be blowing all the air it wants, the engine should warm up to 180..... I'd try another thermostat....  :2cents:

I agree,  might be a defective thermostat.  It was a Stant but I suppose even they have QC issues



This is true! The engine temp should be regulated by the thermostat. The t-stat should open and close based on its set point, regulating coolant temp to 180 deg in this case. This could be a far fetched idea; but the engine also radiates heat to the atmosphere from it's own surface area, independent from the liquid cooling system. Air flow from a stuck thermo clutch increases the heat rejection to atmosphere to some point, possibly lowering the coolant temp at light load below the thermostat opening set point. I have had this happen on a few vehicles, but they were definitely not Hemi Cudas. Just a crazy idea in the process of elimination. :thinkerg:

Yes seems unlikely but a cheap,  quick test anyway

The clutch fan spins free with the engine off but I don't know how to test it other then that
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline 734406pk

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Re: Odd 426 crate Hemi problem, no heat
« Reply #17 on: July 02, 2017 - 05:15:04 pm »
"Yes seems unlikely but a cheap,  quick test anyway"

 :iagree:
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive


Offline 73440

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Re: Odd 426 crate Hemi problem, no heat
« Reply #18 on: July 02, 2017 - 05:20:10 pm »
67 440
73 Barracuda w/ 68 440
65 Plymouth Fury III , I sold ,was my Nana's car till 92 yo.
51 Ford F1 239 Flathead, flipped , new cab , stolen
59 BelAir 283 4 door original patina
01 Chevy van 382,031 miles
06 Crown Vic Police Interceptor
75 HD Ironhead converted to RH shift
73 HD Ironhead
82 HD Ironhead
74 Norton 850
80 HD Shovelhead
80 Husqvarna WR 390

Offline 734406pk

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Re: Odd 426 crate Hemi problem, no heat
« Reply #19 on: July 02, 2017 - 06:00:50 pm »
Testing a fan clutch , https://itstillruns.com/test-fan-clutch-5086903.html

Good article! I tested my OEM fan clutch the same way (440 6 Pack) and found that it was too loose. Changed it out with the Hayden replacement, which felt right but made no difference. 203-205  degrees  all the time, with either fan clutch. It never overheats but that temp makes me nervous...
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline gyman98

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Re: Odd 426 crate Hemi problem, no heat
« Reply #20 on: July 02, 2017 - 11:48:14 pm »
Thanks for the article,  I'll try it tomorrow
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline cudabob496

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Re: Odd 426 crate Hemi problem, no heat
« Reply #21 on: July 06, 2017 - 08:27:22 pm »
Good article! I tested my OEM fan clutch the same way (440 6 Pack) and found that it was too loose. Changed it out with the Hayden replacement, which felt right but made no difference. 203-205  degrees  all the time, with either fan clutch. It never overheats but that temp makes me nervous...

with alum heads, there is an ideal eng temp for max power, but dont recall what it is. Maybe around 200?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline brads70

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Re: Odd 426 crate Hemi problem, no heat
« Reply #22 on: July 06, 2017 - 08:55:47 pm »
Wow wish I had your problems!  :grinyes:  I'd say as others have too, that your thermostat is not functioning properly!
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

My restoration thread 
http://www.cuda-challenger.com/cc/index.php?topic=59072.0
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Offline 734406pk

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Re: Odd 426 crate Hemi problem, no heat
« Reply #23 on: July 07, 2017 - 09:17:35 pm »
with alum heads, there is an ideal eng temp for max power, but dont recall what it is. Maybe around 200?

195-200 deg sounds good to me in this case. The engine runs nice and smooth in that temp range. 6 packs seem to like the extra heat.
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline gyman98

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Re: Odd 426 crate Hemi problem, no heat
« Reply #24 on: July 08, 2017 - 11:42:07 am »
Wow wish I had your problems!  :grinyes:  I'd say as others have too, that your thermostat is not functioning properly!
  I know right,  so weird.  Going to have to try another thermostat



195-200 deg sounds good to me in this case. The engine runs nice and smooth in that temp range. 6 packs seem to like the extra heat.

I will likely stick with a 180 as that's what mopar recommends in their crate hemis
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline gyman98

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Re: Odd 426 crate Hemi problem, no heat
« Reply #25 on: July 22, 2017 - 01:23:12 pm »
Well tried another 180 thermostat still only getting a Max of 160 On the highway
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip