Good afternoon! I'm helping my friend with a 1965 Pontiac Bonneville hearse with a rebuilt 389 but it tends to get pretty hot. We're using the stock rigid four blade fan that came with the engine but it has been recommended to use a larger 18" Derale fan and clutch. The car has a large four core aluminum radiator, but using the original fan shroud. Does anyone have other suggestions? The alternative is the fan driven flex fan version without a clutch. I think my friend would prefer the look of the clutch fan, but which performs better? Thanks so much!
Cooling Fan Upgrade
- Thread starter Lonny Waddle
- Start date
Has the engine block been thoroughly cleaned? If not, changing the fan isn't going to do any thing for the overheating problem. I would never have a flex fan blade on any of my cars, because with time, the flexing blade can stress and break off. If you happen to be anywhere near when this happens, you might be the next occupant of the rear of the hearse. The car didn't overheat when it was in service, and if you restore the engine to its original parameters, it will not overheat today. Cleaning the engine block if the first thing to do.
The engine block was hot tanked and cleaned out when it was rebuilt so I don’t think any thing could be clogged up? I also made adjustments to the water pump impeller to reduce the tolerances. I’ll get the steel bladed fan and a clutch, make sure it’s in the right position inside the shroud and see how it does I guess. I’ll also give it a little more timing.
The 4 core aluminium was a poor choice. You would be way better of with a single E core or a 2 core. What are you running for a thermostats? I would suggest a 180 will do better the a 195. And have you checked the temperature with a difference thremostat? Just for confirmation that it is running hot. I had the same problem with 455 in a 75 poncho limo. Going to the 180 thermostat did the trick for me.
Yep, already has the 180 thermostat and a 1/4 inch hole drilled in it. Also running aftermarket temp gauge. The aluminum radiator was used since finding an original wasn’t happening - and a larger radiator isn’t better?
Not with the aluminum. They transfer heat so fast it with the 3 or 4 core it will heat up the the other one as the hot air passes over them. The most efficient is the e core or the single ones. All the hole drilled in the thermostat does is allow it to burb the air faster. The proper fan might help pull the air faster. The other check is to be sure the heat riser is free on the right manafold. They get stuck and don't open they can run hot.
I’ll check the manifold riser, change the fan, and what’s an E core radiator? I did some online searches and came up empty. I’ll see if I can find a one or two row copper radiator for it - but a ‘correct’ one looks to be about $800. Ouch.
Look up one core Aluminum. One or 2 row aluminum is what you want not copper.