1972 CdV 472 ci Running Hot

[Steve1957]

I have read on old posts here that these cars "run hot." Mine does. In FL. 1500 mile per year driver, with only 36K miles. So: Rad cap's good. Hoses all good, 180 degree thermostat's good. H2O pump's good, belts good, pulleys right diameter. No block or head cracks, no bad head or other gaskets. 3 core Mexican replacement radiator in it - maybe dicey, but holding coolant for the most part. No temp guage. Was running about 225 degrees in the shop the other day, down to 205 in light driving on the road, no traffic. Mech says this is bad, bad, bad. He wants to put an essentially custom 2 tube radiator in it for close to $1K, and if that doesn't do it, ad a puller electric fan system in place of the stock fan. How could "The Standard Of The World" run....hot, stock? Is this just my fate?  Ideas? 

[TJ Hopland]

How old is the current radiator?  And when it was out I assume the AC condenser was cleaned so you know there isn't any restriction there?

Are all the various rubber like flaps in place around under the hood?  At least I assume a 72 had those.

Does yours have a clutch fan or solid?  Its stock as far as you know?

How are you measuring the temps?

Do you have the correct stat that has that extra disc extending out the bottom?  Lots of stats fit but they don't all have that disc on the bottom that blocks a bypass port when its fully open.

$1000 seems high for a radiator unless maybe its a real high quality old school copper one.

[hornetball]

Those temperatures seem a bit warm but not horribly out of line.  I run a 4-core on my '74 Eldo (I'm in TX and the original radiator was 4-core also -- AZ car).

Read this:

http://forums.cadillaclasalleclub.org/index.php?topic=133806.msg287929#msg287929

["Cadillac Kid" Greg Surfas 15364]

Steve,
I don't know how or where you are measuring that temperature but it is not too far off what these motors were designed to operate at.  Typically they will run 120 degrees F above ambient temperature when moving air through the radiator.  I don't believe you mentioned the vacuum advance on your distributor. If you are running too far retarded because the vacuum advance is not kicking in the motor will run hot.
Greg Surfas

[35-709]

Sounds OK to me.  Those engines originally came with 195 degree thermostats, the optional, and only other one available, in a CORRECT thermostat is a 185.  The correct 185 or 195 should look like the first pic. below, other GM thermostats may fit but are not proper for the Cadillac 501 series engines (472, 500, 425).  Pic. #2 will fit but is not correct.

[35-709]

To add emphasis to what has been said and you have read, these engines were designed to run hot for better efficiency and lower emissions  --- it is not "bad, bad, bad", it is normal! 
How experienced with your Cadillac engine is your mechanic.  Check your vacuum advance to be sure it is working as Greg says, and if that is OK then head on down the road with Cadillac joy in your heart.

This is the reason I advise against using a temp. gauge on these engines, people aren't used to seeing those temp numbers and right away panic sets in when nothing is wrong.

[Jeff Rosansky CLC #28373]

 When in doubt, look at the manual. This is out of a 70 manual so everything may not be exact but close enough. Note that the fast idle doesn't kick in until 220 degrees. This is actual coolant temp at a port just under the distributor. Basically, the engine doesn't even think it is hot when idling until 220 so your 225, depending on where measured, isn't that far off.  Also note that the thermostat isn't even start to open until 182 and isn't even fully open until it hits 202 degrees. Remember, a 180 thermostat doesn't keep the engine at 180. In other words, these engines runs hot.
May I suggest before spending money to alter what may be a normal functioning car that you ask your mechanic where he gets his justification for saying it is bad bad bad. He may not be the right mechanic for you.
Jeff

[Alan Harris CLC#1513]

I recall seeing a service bulletin from Cadillac stating that the car is not overheating if it is not boiling.

Is your idiot light coming on? Does the car seem to be overflowing its overflow tank?

[The Tassie Devil(le)]

With the advent of the hotter-running engines, someone mentioned that it was the reason for Cadillac dropping the Temperature Gauge in and installing an "Idiot" light in the Gauge panel as they were getting too many complaints from drivers that were used to monitoring a gauge, and then would be panicking that their car was boiling.

The use of the 15 Lb pressure cap allowed the boiling point to be raised to over 242 F, which is very good for less internal engine friction.

Another reason for going to these higher pressures, the car makers can utilise smaller radiators, which allows lower hood height, leading to less wind resistance, and less total weight.

You need to get the temperature correctly measured, and using an Infra Red Thermometer, you can go all over any engine and you will be amazed just how hot these things get.   And, also how the temperature changed so quickly when testing different parts.   

Transitioning from the Cylinder Head Rocker Cover, across to the  Exhaust Port to the exhaust pipe, things get really hot.   The Coolant liquid has a lot to contend with.

Bruce.

PS.   Once you purchase an IR thermometer, you will spend a day checking all sorts of things for temperature.   Just don't look into the beam.

[V63]

If the car has a fan clutch? It’s the first thing I eliminate if I see one on a car of mine. Opting for the OEM flex fan. Verify your drive belts are snug too!

[bill_boos]

With the advent of the hotter-running engines, someone mentioned that it was the reason for Cadillac dropping the Temperature Gauge in and installing an "Idiot" light in the Gauge panel as they were getting too many complaints from drivers that were used to monitoring a gauge, and then would be panicking that their car was boiling.

The use of the 15 Lb pressure cap allowed the boiling point to be raised to over 242 F, which is very good for less internal engine friction.

Another reason for going to these higher pressures, the car makers can utilise smaller radiators, which allows lower hood height, leading to less wind resistance, and less total weight.

You need to get the temperature correctly measured, and using an Infra Red Thermometer, you can go all over any engine and you will be amazed just how hot these things get.   And, also how the temperature changed so quickly when testing different parts.   

Transitioning from the Cylinder Head Rocker Cover, across to the  Exhaust Port to the exhaust pipe, things get really hot.   The Coolant liquid has a lot to contend with.

Bruce.

PS.   Once you purchase an IR thermometer, you will spend a day checking all sorts of things for temperature.   Just don't look into the beam.

Bruce, in this post you mentioned "You need to get the temperature correctly measured, and using an Infra Red Thermometer, you can go all over any engine and you will be amazed just how hot these things get.   And, also how the temperature changed so quickly when testing different parts.   
Can you share some of the surface temps. I have a Klein tools IR5 thermometer. I am getting readings of over 300 degrees on head corners and center and onlly 180 to 200 on radiator tank top and multiple places on core. Temp guage rises to H. Replaced thermostat with Stant 45478 SuperStat Thermostat - 180 Degrees Fahrenheit. It opens in hot water at 180 to 185 -- don't know how far it is supposed to open.

[35-709]

A properly working thermostat will begin to open at its temperature rating and (assuming a good working cooling system) will vary that opening to maintain a constant temperature.  Throw in trailer towing, mountain climbing, or just a very hot day and the 'stat could be running wide open --- then you have to hope that your cooling system is capable of handling the increased heat load.   

[The Tassie Devil(le)]

Can you share some of the surface temps. I have a Klein tools IR5 thermometer. I am getting readings of over 300 degrees on head corners and center and onlly 180 to 200 on radiator tank top and multiple places on core.

G'day Bill,

I have never actually written down the temperatures I have seen when checking an engine, so you have encouraged me to do just that the next time I check an engine.   The only things I actually write down is the Compression Pressures.

Bruce.

[bill_boos]

Bruce, thanks. Are head surface numbers in the 300's F considered overheating. I am not used to using the IR gun so I'm going to calibrate/validate  on another flathead car that is not showing HOT on the guage. By the way radiator is not boiling over or leaking from the overflow.

[chrisntam]

I wish Steve1957 would have circled back around and told us the results after he did stuff.

I also wish my belly wasn't so big and that we didn't have to pay taxes.

[The Tassie Devil(le)]

Being a pensioner, I don't pay tax, but I wish my belly wasn't so big.

Now, back to the subject.   I can only tell what I have seen on OHV V8's, as I don't have any Side Valve V8's myself.

But, the highest temperatures I have seen are at the Exhaust ports, and they certainly cool down the further away the exhaust gases pass into the exhaust system.

Bruce.