Cooling proiblem

[karl]

77 half w/350 300hp. new 4 core radiator high flow 180 thermostat stock iron water pump electric fan( perma cool (2950 cfm 16inch) no shroud, over heating in stop go traffic on hot days. just bought a high capacity alum water pump. how much will this improve or do i need a shroud? thanks

[mhicks]

I would say it needs the shroud so the fan will pull the air from the radiator only.

[Pyrotechnic]

Yeah it sounds like you need a shroud if you are overheating when stopped.

[68GMC454]

yeah id vote for shroud to.. when i first put my old chevelle together years ago, it did the same thing to me.. couldnt figure it out.. new motor, new everything, then my ex father in law was like i told you you needed a shroud.. turns out i needed a shroud..

[Alex1]

Shroud is your issue -also if you can get a higher cfm outfit -closer to 4700-5000cfm -try the shroud 1st.

[BaddBusa2005]

Put the shroud on or go witha dual e-fan setup.

[piecesparts]

Everyone is saying shroud, but it depends on the type of fan that you are using. The electric fan is a good idea, but if you are not covering the whole radiator, then you are missing out on some vital cooling capabilities. I have some electric fans on my trucks and I run dual 11" fan setups for max cooling if needed. Each fan on my truck is capable of 2850 CFM and that is a lot of air. The fact that you are running a 2950 CFM fan and are still overheating, I would question the core/fan relationship and whether or not you have the fan sitting close enough to get all the air for it from the front side of the radiator.

Now for a secret, that most fan dealers won't tell you. Fans are rated differently at different suppliers. One company will rate the fan on a test bench with the inlet compared to the outlet. This is known as (STATIC) conditons. Another company will rate it's fan with the fan blowing into a restricted area from an open area to create some backpressure. This is known as a (DYNAMIC) condition. Your engine bay creates a dynamic condition and if you have a fan rated for 2800 CFM on a dynamic test, then it is probably moving that much air through your radiator, where the static tested fan will not be.

The temperture switch for your fan is set to cycle on at what temps and does thean fan work when the temps under the hood are high. There are some fan relays that will go to an open circuit when they get hot and shut down on you. (been there- done that)

[BaddBusa2005]

Even with an efficient super doooper fan, if it doesnt have a shroud it is just moving air that doesnt need to move. Put a shroud on it and it will take care of it.

[piecesparts]

Originally Posted by BaddBusa2005

Even with an efficient super doooper fan, if it doesnt have a shroud it is just moving air that doesnt need to move. Put a shroud on it and it will take care of it.

There are many fans that are sold with the kits that mount them up against the core fins. It is hard to build a shroud for that design. The ones I purchased came with their own shrouds, so I had no problem, but if there is no shroud, then a redesign is a thing that is coming.

[Jimbob91]

Get a shroud. Cheap, easy, it'll work.