Overheating

[dostal]

I rebuilt 326 in my 66 Lemans and I'm now having an overheating problem. I replaced the original water pump and I've added a fan shroud that helped a little, but I'm still running about 205 degrees when at idle in a car cruise. Any other ideas I should try?

Mark Dostal
Coos Bay, Or

[GPModJ]

There's an extremely long thread on the Heating & Cooling section of the Performance Years tech forum. The consensus seems to be that the single most effective thing you can do is, first, ensure you're waterpump has a cast impeller and, second, that the clearance between the divider and impeller is about 0.020." More clearance decreases the effectiveness of the pump.

Other things to check include timing (too much advance or retard?), carb jetting (too lean?), vacuum leak (that would also make it idle too fast), fan, and thermostat (not allowing enough flow?).

[Icelander]

The 400 I just pulled apart has almost a quarter inch of clearance between the stamped impeller and the divider plate. I wouldn't be suprised if this was the reason the engine was scrapped.

Does anybody know where I can go to get a WP with a cast impeller?

Kendall

[GPModJ]

Super Dave sells aluminum pumps with cast impellers. They're cheap too.