348 Overheating problem

[ordway59]

Hi Folks-
I'm new to the site. While sitting still my 59 Impala overheats in about 10 mins. Radiator is new, fluid is good, thermostat is new, engine runs ok. I'm thinking water pump. Any quick diagnostic tests to help?
Thanks!
Gary

[MRHP]

Check your fan clutch. It should really be stiff to turn when engine is hot. If not buy a new one. Also make sure fan blade is installed correctly to draw air through radiator. I have seen both problems many times over the years. Hope this helps!

[Old School]

Hi Folks-
I'm new to the site. While sitting still my 59 Impala overheats in about 10 mins. Radiator is new, fluid is good, thermostat is new, engine runs ok. I'm thinking water pump. Any quick diagnostic tests to help?
Thanks!
Gary


Leave the cap loose and heat it up and check inside the radiator for water circulaton. YOu should be able to see a good flow. If the water is still, your thermosat is stuck or the pump is bad.

[Ronnie Russell]

Gary, Welcome to this site. All the suggestions are good and are a good start. If you "search" cooling systems in this section, you can find much more good advice. :)

[rstreet]

Gary look for an all summer posting by Denis (despience) great stuff in that one but you'll be a few days reading it:rofl . Also check to see if the fan blade is half in the shroud and check your vacuum advance also
Robert

[blumun53]

My first thought on this is, "Does he have a fan shroud?" And if you do have a shroud, is it a 6-cylinder shroud? The 6er is shallower than an 8er. I'm assuming you run a V-8. Does the engine cool down after you start moving? If so, there's not enough air flow through the radiator. The fan needs to be semi-close to the shroud opening, or it can't suck air properly, especially if you run a fan clutch. You can have good everything, but if you can't funnel the air properly, it's like pouring a gallon of beer on your face, but only being able swallow about a glass full of it. Most of it goes unused. The 59 I had did not have a shroud, so I compensated ( for lack of funds at the time ) by spacing the fan closer to the radiator. But this was simplified by the fact I did not have a fan clutch on it. Good luck!! :cool:

[jpekarek]

Here's an often overlooked overheating problem. Do you have enough initial timing? Are you running vacuum advance? The more timing you have at idle the cooler the engine will run. Many people set their static timing at 4-6 deg. advanced then they don't use the vacuum advance. This will very often cause heating at idle. At idle, your timing should be advanced approx 14-16 deg. (including vacuum). Most stock distributors come with about 30 degrees of mechanical advance built in to them. So you set your total timing at 32 deg and your idling at 2 deg advanced. Or you set the idle at 8 deg and the thing backfires at speed. In this situation there are 2 options. 1) Use your vacuum advance or 2) Modify the mechanical advance by limiting the weights in some way.

Not sure if this is the problem you are having, but just a suggestion. James.

[dq409]

One more item to look into is lean carb mixture.
Water flow, thermostat, fan, timing, carb settings can all lead to over heating.

[ordway59]

I believe that I do have the correct 348 fan shroud - it is more shallow than the 283. The fan blade install appears to be the same as the Chevy drawings i have. Anyone have a photo showing the proper orientation? I'll try some of these suggestions, too.
Gary