Classic/Antique Car Repair: 1966 Mustang GT, newport beach ca, acton ca

Question
This Mustang has been in my family for 40 years. Since about 1969 it has had a radiator overheating problem.  I even changed out the engine about five years ago. The radiator still overheats and blows the seams.  I have tried different caps and thermostats.  Why does it keep developing so much pressure? Do you know a mechanic in the Newport Beach, CA area who you would recommend? Also, I had a friend, Todd , in Acton, CA who owned about three Packards, do you know him?  

Answer
There are so many possible causes that I can only list them and ask you to run down the list to find things that you might not have already eliminated.

First, how does the car run?  If it has normal power, that eliminates a large category of causes (restricted exhaust, incorrect timing or carburetion etc).

Second, was the block every cleaned out? By this I mean were the core plugs pulled and the water jackets hot tanked or purged with high pressure water and probing tools to get the mud out of the crevices?

Third, does the car have all the factory shrouding around the fan and radiator, so that the air flow is the way the engineers designed it?  If any ducting or fan shround isn't right or if the fan blades are non stock, this can make the car overheat at low speeds.

Forth, has the spring been removed from the lower radiator hose?  Very commonly, mechanics don't understand the purpose of the spring, and take it out.  Then when the car is driven at high speeds, the lower hose collapses due to the vacuum pulled by the water pump.  The spring is there to prevent this.

I must comment that if the radiator cap is correct, the radiator should not have been damaged when the car overheated.  The cap is supposed to release the pressure at 15 PSI or so.  If the radiator blew at 15 PSI, it must have been very corroded, and might have been the cause of the overheating in the first place.

I'd like to have your comments on these thoughts, and then we'll take the next step - these are the things I'd check if I were right beside the car.

I don't know of anyone to recommend in your area, sorry.

I don't recall Todd, but he probably knows of me if he is in the Packard hobby - I've been playing with Packards since the 60s, and still have quite a fleet of them.  He's probably at the big Packard swap meet today in fact, at the Doubletree in Orange County.

I hope this is of some help.

Dick