Help with cooling problem on a 64 Impala

[TS6]

My buddy just bought a nicely restored 64 Impala SS clone, with a rebuilt 283 and all new cooling system components. New radiator, hoses, stat, fan, etc. He brought it over last night, and I noticed this thing is running close to 220! I checked the coolant, its full, and clean, and the hoses have pressure on them when running. If you rev the engine at all it cools right down. We were sitting at a light and it was creeping up, and as soon as he gave it a little gas, it cooled about 20 degrees. I'm talking like a LITTLE gas, like the car moved maybe 3 feet. Not sure what stat is in the car, but I figure it would be a 190 or 195 at the most. The shroud is there, and the fan blade is positioned correctly in it. At this point, since the water pump is new, I'm going with an inadequate fan. Its a stock looking 4 blade fan. Compared to my buddies 6 blade "performance" fan, this thing moves very little air. Both cars have no fan clutches either, before you ask. What else could it be? I'm going to try a new fan tonight, just can't find anything else wrong.

 

[wlaukaitis]

Are you sure it has a stat? Maybe it is in backwards? Maybe it needs to be burped? How is the timing? Is it on the mark? Is it running lean?

 

[turbosam6]

Checked all those things, seemed fine. Usually cars with no stat run cooler.

 

[zam70]

If the car over heats while sitting still, 99.9% of the time it is an air flow problem...I think you are on the right trach with the fan.

I would, how ever, verify the thermostat (that it has one).
A missing t-stat can cause it to run to cool or to hot. It really depends on the hole cooling system.

 

[84GNPILE]

I kinda think it has an air pocket in it.Is the temp sensor in the top of the intake or on the side of the head?If it's on top I think there's an air bubble in it that may only be small enough to effect the sensor at a standstill.If it's in the head I would think a defective water pump/T-stat,loose belt,or inadequate fan.

I would think a stock fan could cool a 283 as long as it's turning at the correct speed.Even a replacement "flex" fan without a fan clutch.

 

[Buick From Hell]

sounds to me like maybe the water pump simply isn't pumping water fast enough at idle. Was it changed?

And being an old 283, who knows how much crud is hiding in the water jackets, along with who-knows-how-much alumaseal or other stopleak clogging things up. (boiling the block won't necessarily get all that crap out! Ask me how I know...)

 

[TS6]

Thanks for the help so far guys. I replaced the stat yesterday, no help. Tonight I'm going to put a larger spacer on the fan to bring it closer to the radiator and further into the shroud. Everything is new with 1700 miles on it. I'm also going to try another guage, just in case. Right now I'm kinda thinking the radiator, although new, is too small. I believe its a single core. Running out of options.....