In May 2002 I posted the same issue about
my 1967 Chevelle SS running too hot at idle.
Runs at 180 degrees while cruising. Starts to
creep up when at idle.

The 67 Chevelle SS has the original 396/325 engine rebuilt. The radiator is the original
Harrison, apparently recored in with a four
row in early 90's. Has a shroud. Vacuum and
timing ok. Radiator guy says radiator is running 31 to 32 gpm (versus the chart which
calls for 40gpm). The 165 thermostat was
just replaced with 190 themostat.

Again, car starts and runs fine at cruising
speed. At idle it begins to creep up to 210,
then 235 and higher. Must shut it down.

Thermal clutch was installed and replaced the
flex fan.

We believe it is radiator and I am thinking of having custom radiator made (leaning toward aluminum). Maybe new high water flow
water pump.

Second opinions please.

Thanks for your advice.

Ken McD...

Read this before you order.... www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)

Airflow is the problem and/or the radiator is not big enough to dissipate the waste heat. Aluminum is your only solution, it's the best or trying a bigger fan(s). Go to www.streetrodstuff.com/Products/157 (http://www.streetrodstuff.com/Products/157) for a great custom radiator, crossflow, to your specs for under $300. I know these guys and they are excellent.

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Steve Jack
-Concept One Pulleys and Brackets
-Engineering & Marketing Technologies
-Northern/Southern Rodder Magazine's "Jack'Stands" technical column author/originator

my understanding is copper is a better heat dissipater than alum. although the alum is lighter. more cores with high efficiency fins with an over flow bottle and cap should help

How can the original radiator which has been made bigger not work? The factory radiator was up to the task.

Find somebody who has one of the digital point and shoot temp gauges and scan all the parts of the system. The radiator may have a area that is blocked.

If that is okay then think about a Stewart Stage one pump, looks like an original pump but works much better.

If the car is an automatic, you can take the trans lines through a seperate cooler and reduce the load on the radiator as well.

Car have A/C???


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www.muncie4speed.com (http://www.muncie4speed.com)
Gold 67
1967 Malibu, 2nd owner.
1971 Malibu, been in the family since new.
There is nothing like rowing through the gears at 7500. Stick cars are so much fun they should be a controlled substance!

[This message has been edited by Wally (edited 07-04-2002).]

Camaro67Chevelle68......you have learned the properties of elementary heat conduction physics well, but there are several other issues that enter into the whole radiator design that affect the ultimate outcome of the cooling in the end.

Don't feel picked on, you are not alone in your belief about this important subject and the differences thereof. Read on.

The aluminum radiator is the best overall product on the market for the dollar today. This is not to say that the radiators made from copper/brass/solder are not good, and if you have one that works, don’t go out and change for the sake of change. But, the choice of aluminum construction will outperform their copper/brass counterparts quite easily even though copper is a better conductor of heat. Aluminum construction overtakes the copper with more surface/fin area available for DIRECT heat exchange with larger tube designs. Aluminum essentially quantifies the subject. A typical 1.25”, two-row, aluminum radiator will outperform 4 or 5 row copper/brass brethren by as much as 35%! Larger tube construction also offers higher heat dissipation due to increased flow, stiffer structure due to the aluminum welds and material strength, making for a less likely leaky situation due to torsion and vibration stresses. Also, the fact that more, if not all-modern cars are implementing aluminum radiator technology because of this fact and allows for smaller radiators per hp generated.

Copper/brass/solder radiators are just okay technology compared to what's available today. Copper radiators are smaller tubed due to limits of strength, and restrict flow, offer smaller overall area for heat dissipation, and have to be soldered together which is a very poor conductor of heat. Combine that with lot's of rows, which inhibit cooling capacity as you work your way to the rear tubes, makes the aluminum a better choice.

I didn't catch the first time that you have a clutch flex combo! That's the problem. Old time flexfans are junk at moving air. Only the new technology Derale heavy duty fans can move enough air to be used. The combination with clutch, which reduces air moving capacity as well, but were used with major sized mechanical fans that produced enough air to cool, will cause this.

Either, get a big Derale Heavy duty flex fan and dump the clutch, or put the heavy duty original back on. This will fix the problem if the clutch is okay!

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Steve Jack
-Concept One Pulleys and Brackets
-Engineering & Marketing Technologies
-Northern/Southern Rodder Magazine's "Jack'Stands" technical column author/originator

[This message has been edited by HOTRODSRJ (edited 07-04-2002).]

Gentlemen:

First, many thanks for the responses. I have had the original Harrison out of the Chevelle
SS. I already brought it to an old radiator
guy. He did a complete check up of the radiator, cleaned it, and had it improved
from original 27 gpm to now 32 gpm. He advised me chart specs call for 40 gpm. We
put it back in Chevelle. We adjusted timing
and vacuum advance. Car has new cam and
valve springs. Has new fan clutch and heavy
duty 7 fan blade.Has shroud in place. Runs like a charm. But, only heats up when sitting at idle. Otherwise stays at 180 when running. If it heats up and then u drive it, it goes down from 210 to 180.

Therefore, we have narrowed it down to either
the radiator (primarily) or the water pump.
I could have the radiator recored. But, I am
gonna take Hot Rods advice and buy one of those custom made aluminum radiators. Then I
may consider a Stewart Warner or Tuff Stuff
high flow water flow. These two additions
should solve this dilema.I will keep the original radiator if I ever decide to sell,
which is unlikely now.

Regarding the aluminum radiator, I plan to
paint the top and side tanks only black. Is
Eastwood Radiator black a good paint ? Other
paint suggestions ?

Thanks guys.

Hot Rod, I talked with Dick.

Ken McDee

Thanks for all the info on copper vs alum radiators. Can anyone tell me anything about the following:
"careful and don't get a water pump with to much flow or the water will not have enough time in the radiator to cool prior to going back to the engine"

<BLOCKQUOTE>quote:</font><HR>Originally posted by Camaro67chevelle68:
Thanks for all the info on copper vs alum radiators. Can anyone tell me anything about the following:
"careful and don't get a water pump with to much flow or the water will not have enough time in the radiator to cool prior to going back to the engine" <HR></BLOCKQUOTE>

I've read that at some radiator and water pump sites as well. Makes sense that since the radiator's function is to reduce the heat in the water.

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TC Gold #92/ACES #1709
67 SS & 67 Elky
GR8PMKN (http://www.dalesplace.com/images/chevelle/more_pics/p001182.jpg)

Dale's Place (http://www.dalesplace.com) Team 67 (http://www.team67.com)
Midwest Chevelle Regional Governing Council (http://www.midwestchevelles.com)
Integrity: If you have it, it doesn't matter - If you don't have it, it doesn't matter.

Gosh guys, I am disappointed. I have a world class education with a very informative cooling forum, used to design Nuclear plant cooling systems and now do cars etal and no one reads my comments or goes to the forum.

My feelings are hurt, but I will save you the trouble on an old myth about flow, since you asked.

Contrary to popular believe and long time myth, slowing the coolant through the radiator DOES NOT improve heat dissipation! I can’t emphasize this enough. This is a widely held myth that is completely contrary to the laws of heat conduction physics. The higher the flow, the more heat will get absorbed and dissipated. Stock water pumps are generally okay for stock engines, but are antiquated technology by today’s standards. The high performance pumps are a step up in cooling technology and reliability and will help cooling capacity. Why do you think those things were invented?

And if you want another opinion of another world class cooling engineer, go to http://www.stewartcomponents.com/advanced_cooling_system_basics.htm and look at the tech facts. Same answer there too.

------------------
Steve Jack
-Concept One Pulleys and Brackets
-Engineering & Marketing Technologies
-Northern/Southern Rodder Magazine's "Jack'Stands" technical column author/originator


[This message has been edited by HOTRODSRJ (edited 07-05-2002).]