If it really is the original rad, as you think, I would bet money that is your problem.

Also if you can, remove the block drain plugs undeneath the exhaust manifolds ( usually a 3/8 pipe thread with 9/18 hex head) and you will be able to see if there is any sediment rust accumulated between the cylinders (with the help of a small probe).

Not that it couldn't be something else also, but a cooling system of sufficient capacity, will acount for any incorrect tuning issues.

Simply, if your cooling system is big enough, and you run a 180 thermostat, your guage will always read 180, at high speeds, low speeds, at idle, with or without a/c etc.

Some cooling systems are designed by manufacturers with little extra reserve, for cost, space, profit reasons and hence possible minor temperature fluctuations.

Here is a link you may find interesting
http://www.arrowheadradiator.com/Why...verheating.htm
If you really want a good primer on cooling systems, read about the over the road trucks. They take their cooling very seriously.

 

first, increasing the cooling capacity to mask other problems is simply solving the symptom, not the problem. The problem still exists. If for example the issue is in tunning, incorrect timing, etc the problem would still exist and can coause other more serious issues if not resolved.

Second, 180* t-stat will not limit the temps to 180* no matter what the cooling system capacity is, the t-stat will only dictate the minimum operating temps, not how high the motor want to run at.

IF a new radiator is required because the old one is just plain shot, worn out, damaged, or whatever, than a new aluminim DeWitts radiator will offer approx a 30% greater cooling capacity over the stock b/c unit, but to just throw money and replace parts especially on expensive parts like a new radiator is foolish until the true cause of the problem is found.

Overheating is a symptom of a problem and that problem needs to be found, not just masked by overcoming it with a larger capacity cooling system.

I will agree with you that the manufactures don't usually go too overboard on excess requirements. Corvettes in particular have always been somewhat borderline on their cooling capacity, but as long as everything is working correctly, all the parts of the system are in place including the seals and airdam, etc the stock system is perfectly capable of cooling the car is all conditions without resorting to extreme measures.

 

I think you misunderstood.
Nothing is being masked at all.

If you have tuning issues solve them separately, but don't assume tuning, will solve overheating problems.

Simply put, the system capacity keeps the temp down, the thermostat keeps the temp up, thus this constant interaction will always keep the cooling system at the set thermostat temperature.

As mentioned previously, this is a good place to start to diagnose (before spending any money):
Quote:
Originally Posted by noonie
If it really is the original rad, as you think, I would bet money that is your problem.
Also if you can, remove the block drain plugs undeneath the exhaust manifolds ( usually a 3/8 pipe thread with 9/18 hex head) and you will be able to see if there is any sediment rust accumulated between the cylinders (with the help of a small probe).

In the link, you will see that his symptoms are consistant with decreased capacity.

 

High speed overheating is usually related to either to much advance timing or the spring in the lower hose is gone. When the engne is cooled down, grab that lower hose and see if you can squeeze it closed. If so, then the metal spring is toast and the hose collapses at high fluid velocity.

 

if I misundersttod it was because of the way you worded this......... to me that sure sounds like you are saying that a cooling system of enough capacity will account for incorrect tuning issues. That means masking a problem........

Obviously from your last post though you and I DO agree that tuning issues must be resolved regardless and that it's important to check to make sure everything is else is also up to par before just throwing money at other parts such as expensive radiators.

Even Tom, who I'm sure would love to sell a new radiator, is suggesting other alternatives as being more possible culprits.

 

lol

I'm still betting on a plugged cooling system.

One important factor in the equation is that the car is in sunny hot Florida. People here just don't seem to do the flush antifreeze thing regularily, like you do up north.

I know lots of people here that overheat every car they get. they just always add water which promotes rust and the problem gets more compounded.