I want to get my 63 to cool down better. It is a non ac car w/o a fan housing. It has a flex fan on it but the gauge goes to the middle in just a few miles. It has not over heated. I had the old Harrison rad cleaned out a while back and isn't leaking. I have a 50/50 mix of  fresh coolant in it. I was just wondering if anyone had any suggestion about cooling her down. I have thought about a 160 degree thermostat also.

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Check to see the -heat riser- located in the exhaust pipe --just below the drivers exhaust manifold is working ( opening ) as it should be when the car is at operating temp
Look for the video in the header -- under Videos To see it working

Check your thermostat to see if it is opening as it should
It should open in a pot of boiling water ( 220 degrees )
I would stay with the 180 degree thermostat myself and solve the heat issue

Use two gaskets on the thermo housing
Get the slant ( i think thats the name ) thermostat
The one that stays open when it --breaks

They sell liquids you can add to the cooling system to lower the temp 20 degrees

If the fan clutch ( flex fan) is not operating correctly that could be the problem
That fan works mostly at lower engine speeds and less at higher speeds

Half way on the temp guage is 200--220 degrees
The engine can run at those temps as long as the cooling system is not boiling over on you
Good to get all to run at the recommended 180 degrees though

I always use a rad cap with the release handle to prevent being burned by hot coolant
Because it's not if you will overheat at some point in the future but When !

Installing a fan shroud that comes on the stock AC cars will help the temps reduce

Getting the above right will reduce your temp

Possible the guage itself may need some attention or the sending unit as well

Get a true rad operating temp with a tool that goes in place of the stock rad cap to check the guage


The video of the heat riser working --has been moved to the --Help pages - in the header on the home page



The cooling fins may have come unbonded from the cooling tubes in areas. That will affect the heat transfer and cause the engine to run hot.

A new radiator may be in order if the inlet temp and outlet temp are not far enough apart. Your radiator shop should know how much the radiator should be cooling the coolant down by.

Or the water pump is not up to specs. There was a time not too long ago when poor quality water pumps with crappy impellers and incorrect clearances were flooding the market.

Or the carb is running lean causing the engine to run hot.

Thanks I will check into it. Any after market Radiators you would suggest? There a ton online at all different $. 

I know from experience that a radiator shop can tell if a rad is very clogged by its Weight when out of the car
They get heavy when they have debrie in them

Russ good point sbout a possible bad water pump if that job was done fairly recently


Based on your year Cadillac be sure the inlet and out let of the new rad are in the same location as yours now
The 65 -67 are on a different locations due to a frame change
Be sure the lines from the trans cooler at the base of the rad are the correct size fittings as you have now or you will require an adappter of some kind there
Teflon plumblers tape should prevent leaking at the trans fittings

Check the trans fluid level after the rad installation for possible fluid loss after the new rad goes in


If you do get a new radiator, do not get an aluminum piece. Copper dissipates heat better than aluminum, and you can get factory size new original radiators.

Good to know Thanks  I am going to take it to a local rad shop and go from there.

Before you do anything else you need to be sure your car has had a new good tune up on time
Is your tune over due ?
These cars get tuned every 6 thousand miles

Retarded timing will cause the engine to --run Hot
The timing retards normally --as the point wear out
The incorrect timing will cause the car to hesitate -as well

Have the car tuned if it is due and a good chance that will correct the heat issue

If it does not correct it ( and it should ) the other items i mentioned above SB investigated and you will have a new tune up that is always a good thing to have


Yep had my 63 do the same thing,I tried new radiator new thermostat new fan, ended up installing twin thermo fans with an adjustable temp control switch

Are you sure it is overheating? The new replacement aftermarket temp sending units are known for being miscalculated and showing too hot ... but usually pegging out toward the end of the temp gauge scale.  Under normal driving conditions 1/4 to 1/2 on the gauge is normal.  A fan shroud and an original 5 bladed clutch fan or 7 bladed non-clutch fan used on the AC cars should help.  

To know exactly what temps your engine is running at, a digital IR heat gun is a good investment and can pick them up at a reasonable price at auto or home improvement stores or Amazon. I carry mine wherever I go!  With the standard 180 degree thermostat your engine should be running between about 195 and 200 degrees on the engine block near the temp sending unit. If you need a temp sending unit I have VG used for $10.   Ialso have the fan and shroud if interested.  Email me at jasonedge@nc.rr.com



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