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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Engine Cooling problem

  • Thread starter Thread starter 989153
  • Start date Start date Aug 16, 2019
9

989153

New Member
Jul 1, 2019
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Hawaii
Aug 16, 2019
#1
  • Aug 16, 2019
  • #1
I have a 65 coupe with a 302 swapped from the 289. I can’t seem to get it to cool. Replaced thermostat and just replaced the radiator. After a brief 5 minute drive it was too hot to touch. Any ideas?
 

dennis112

15 Year Member
May 15, 2005
1,561
36
79
Amish Wonderland of Central PA.
Aug 17, 2019
#2
  • Aug 17, 2019
  • #2
989153 said:
I have a 65 coupe with a 302 swapped from the 289. I can’t seem to get it to cool. Replaced thermostat and just replaced the radiator. After a brief 5 minute drive it was too hot to touch. Any ideas?
Click to expand...

Were the head gaskets replaced?
 
9

989153

New Member
Jul 1, 2019
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Aug 17, 2019
#3
  • Aug 17, 2019
  • #3
No
 

dennis112

15 Year Member
May 15, 2005
1,561
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79
Amish Wonderland of Central PA.
Aug 17, 2019
#4
  • Aug 17, 2019
  • #4
Have you verified timing? If it is retarded or advanced too far it will run hot.
 
9

989153

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Jul 1, 2019
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Aug 17, 2019
#5
  • Aug 17, 2019
  • #5
I’ll check that tomorrow. (Obvious question) Would the water pump affect it
 

dennis112

15 Year Member
May 15, 2005
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Amish Wonderland of Central PA.
Aug 18, 2019
#6
  • Aug 18, 2019
  • #6
989153 said:
I’ll check that tomorrow. (Obvious question) Would the water pump affect it
Click to expand...

Not unless the impeller is not connected to the shaft. The stock water pump normally works quite well.

Corrosion can cause various cooling issues including blocked passages. Was there any sign of rust in the fluid when you replaced the radiator? Also did you use a 50% (or less) antifreeze/cooling mix?

When the radiator sits overnight (after being ran until hot) can you still see antifreeze in the upper tank? (An inch down is OK if the car is not using an external reservoir.) If the motor seems like its consuming the coolant, then there is a serious internal issue.

How is your radiator cap? Is your radiator still full? Any bubbles seen in the radiator when the cap is removed? Flow (agitation) without bubbles is a good sign.

If you carefully place your hand on the top tank and then the bottom tank does the lower tank feel cooler? (A cheap hand held inferred temp gauge would be safer.)

Is the car running lean? Could be an uncapped vacuum hose/bad carb.
 

zookeeper

Founding Member
Aug 25, 2001
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Rogue River, Oregon
Sep 12, 2019
#7
  • Sep 12, 2019
  • #7
Why are you touching the radiator? At the risk of sounding like a jerk, I'd go by the gauges before I started slapping my bare skin on things. 180° is hot enough to burn you yet perfectly normal.
 
G

GOvert

15 Year Member
Jan 27, 2007
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north central Tennessee Valley
Sep 21, 2019
#8
  • Sep 21, 2019
  • #8
Is the thermostat in the 180 to 190 degree range? A common mistake I've seen many times is the thermostat will get replaced with a 160 or left out all together. Too low of a number on the t-stat doesn't give the radiator enough time to cool what is in it before cycling open again.
 

2Blue2

will be trying this sex one when I can find it
Mod Dude
Mar 5, 2019
4,430
2,893
163
Oahu
Sep 21, 2019
#9
  • Sep 21, 2019
  • #9
Things not mentioned yet

Fan Shroud?
W. pump intake hose collapsing
Radiator clogged with a fresh batch of scale from a motor thats been sitting
Vacuum leak on carb?
Carb jet partially clogged making lean condition
system not burped

Good luck keep us posted
 
G

GOvert

15 Year Member
Jan 27, 2007
485
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48
north central Tennessee Valley
Sep 23, 2019
#10
  • Sep 23, 2019
  • #10
Impeller rotted away?
 
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