My small block 350 is overheating when it's at idle. Has cooling engine fan . Fan shroud an d or electric fan has been suggested to fix problem. What's would work best? Trucke
With kind of assuming things based on the limited information, assuming a mechanical fan with no shroud that only overheats at idle. If the case, airflow is the issue. If the fan is of adequate size and has enough blades to move enough air, a shroud will fix it. That is also assuming the radiator is of adequate size and the fan is close enough to the radiator.
Pictures will help us see the bigger issues. At least the obvious ones. Without that, shrouds are usually a good improvement.
It sounds like the radiator is of adequate size and construction. Is this a new installation? Old installation that has changed? Going back to your original question, I am more of a fan of a shroud than electric fans.
Yes never did come to any solid reason for the compression problem. Motor is running good after reassembly .Trucke
Cooling is an engineered science, and the OEM folks do a pretty good job of it. I approach it this way- what did the engine come out of- that way I can research how many square inches the OEM radiator was, what type of fan was used, etc. That should give a good baseline to start.
How hot is this "overheating" what temp is it getting up to? Have you verified the temp with a heat gun or temp gauge in the radiator. Is it puking coolant on the ground? Top tank radiators need air space in the tank for coolant expansion and if you fill it to the top it will for sure puke over until it finds it's "happy with it" level. What thermostat are you running? Correct belt setup for the water pump? Getting hot at an idle and cooling right back down above 30 mph is an air flow issue for sure. Been there done that with my 48 and too small of a fan that didn't cover enough of the radiator. Now how hot is "too hot".
Biggest copper radiator you can fit. ( yours is small like mine) biggest fan you can fit. Lots of advance. That’s my advice.
Water boils at 212 F at sea level, lower than that at altitude. For every pound of pressure the radiator cap adds you get 3 degrees more to the boiling point. So a 10 pound cap would make the boiling point 240 degrees F. (I am pretty sure that is correct but never trust the internet, it has been known to be wrong) Sooo, are you running a cap? Is it pressurized? Are you sure it is seated in the neck as well as on the radiator cap surface?
Sometimes the flow rate can be too high forcing the coolant out the rad neck before it can return to the engine cooling system. If it is puking at 210, I would slow the flow down. That is not a boiling over problem. Also, have you tried using a cap with a higher pressure rating, this will fight to stop overflow. Warren
16X23.... That seems tiny for a 1940 Chevy. That’s about the size of the radiator for my ‘64 Fairlane. Fairlanes and Mustangs had tiny radiators. Also the shape of the engine compartment was flat compared to the big and tall 1940 compartment. I think the radiator is not compatible for this application. I’m don’t have the dimensions for a 40 Radiator but it’s rather tall.
1940 Chevy Truck radiator..... Core size 22 1/2” x 18”x 2 1/4” Tank size 3”x 18 1/4” Overall size 28 1/8 “ high x 22 1/8” wide
and the question is how long at idle, sitting in a cruise traffic jam can mean no movement meaning no airflow, or a few turns of the traffic light 5-10 min. do you have A/C ? also how tight is the engine compartment, the air flow through the radiator has to exit the engine compartment, if you turn on the heater does temp go down
Does the temp initially drop when the thermostat opens and then continue to climb or does it just climb? If the temp doesnt initally drop, the thermostat may be in backwards. Just a thought
210 sitting idling isn't hot as far as the engine is concerned, if it is a 350 it probably ran down the road at a higher temp than that as it's normal temp but the minute a guy puts one in an old car or old truck he pees his pants because it got over 200. If the level has settled to around 1/2 to 1 inch above the core when cold that is where it should be. If you are seeing 23o or so at and idle then it is hot. If it is going up to 210 at a stop and then right back down to just above the thermostat rating it is air flow that is the issue. On a Chevy truck radiator with a 16 inch fan over half the radiator isn't getting any air pulled though it at a stop if you don't have a shroud. Been there, done that own the shirt.
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