Question56 bird 312 v8. Overheats in traffic. OK on highway
What should I be looking at?
AnswerThere are a very large number of possible causes of overheating. Since the car seems to be OK when moving rapidly, my first guess would be that there is a problem with the fan moving enough air past the radiator core at low speeds. Reasons for this could be:
1. an incorrect fan blade, either the blade itself or the way it is mounted - verify that it is the original fan, and that it is mounted right way forward (curvature of the blades such as to cup the air and direct it back toward the engine) and that it is within a 1/2 inch or so of the radiator surface.
2. A slipping fan belt
3. A missing shround around the fan, or missing rubber flaps to seal the spaces around the radiator so that air is forced through the radiator, and not around it.
4. blockage due to some other item mounted in front of the radiator, or accumulation of dirt or bugs in the radiator core openings, or a buildup of too much paint on the radiator itself.
If all of those things seem to be OK, just the way the factory built it, then you need to have the radiator "flow checked" at a radiator shop, and if that checks out OK, the next step is probably to have the core plugs (AKA "freeze out plugs") removed from the sides of the block for a complete flushing out of the accumulated mud and crud that always builds up in engines over the years.
These cars often act like this if AC has been added to the car - if this is the case, you may have to obtain a much more capable core for your radiator.
Give me a report, please, to guide me further.
I am assuming that the engine runs fine, with normal power - if not, let me know, as there are many other things to check if the power seems down.
Dick
