Too Hot

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Mrpoopypants

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I have a prob with cruiser getting to hot when at idle. When driving the temp drops but as soon as i stop and sit for a few mins the temp shoots up.
I have a Chevy 350, 3 or 4 core rad with flex fan and no shroud? what would be the best way to fix this prob?
Previous owner could not find a shroud that would line up correctly so he suggested going with an aluminum rad w/electric fan. Any suggestions?
Thnx
 
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I had the same problem with my Vortec install. I went to a good rad shop. They said if it stays cool on the road that you have plenty of radiator cooling capacity. Air flow is the problem and you need to have a shroud to get the air flow. I also did not have a shroud.

I ended up getting an electric 'monster fan' from vintage air. I also got the universal plastic shroud that goes with the fan. I had to modify the shourd a bit by cutting in down slightly to fit my radiator. I pop rivited some 'lunimum sheet on to it to close off the part I had to modify and I put foam between the shroud edges and the radiator to seal it to the core. I then took the whole thing back to the rad shop and they soldered some studs to the radiator tanks and the fan mounts to those. Do not mount the fan to the radiator core using those special zip ties that you poke all the way through the radiator core. All the bouncing around while wheeling will eventually crack the tubes. They are not designed to support any additional weight.

I have participated in several radiator cooling tests for diesel powered mining equipment and having a shroud that is sealed up to the radiator core makes a huge difference. The object is to not let the fan pull air from anywhere but through the core. Another thing that helps is sealing up the areas around the radiator itself so warm air from the engine compartment doesn't recirculate through the radiator.

Good luck.
 
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I run a 350 without shroud and had some heating probs too. Check your timing. Mine wanted to be advanced a couple degrees more than I had it. Works ok now.

Still need a shroud but it's winter so there are more important things to do.
 
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The object is to not let the fan pull air from anywhere but through the core.

I agree vortec62. A lot of people try adding vents ect to the hood or sides of cars to increse ventilation in the engine bay which causes a pressure build up and slows the rate of air passing thru the radiator.
 
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First, I'd suggest using something other than a flex fan. They are good at high RPM's of getting out of their own way (i.e. getting out of the way of moving air) but are not good at pulling air at low RPM's when needed. Do you have a space issue that would prevent the use of a good clutch fan and shroud? If not there is the answer. For a thermal clutch fan keep in mind it engages based on air temp coming from the radiator. That means not using a shroud allows it to pull cool air from elsewhere and delays engaging the clutch until water temps in the radiator are very high.

If you do have a space issue and can't fit a clutch fan, go to a GM dealer and get part number 405422 (steel blade high pitch fan) and build a shroud to fit.

Let us know how it goes.
Rice
 
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Mrpoopypants

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Thnx for all the good tips. I do have quite a bit of space from the front of the engine to the rad. The fan itself is on big spacer and there is at least 1 to 1.5" from the fan to the rad. I will start with a shroud. then a new
Clutch fan. Going to Do a frame off starting in a few weeks. So will post what worked.
Thnx
 
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on a rod prodject (droped a 454 in a camaro) we put an electric fan infront and behind the radiator. it runs cool at all speeds. just a thought
 
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Mrpoopypants

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Thnx again for all the good advice. one las question.
For some reason i had the idea that the fan blew air on the engine to cool it :rolleyes: I gather now that the idea is to get the right amount, or just a large amount, of air to flow or be pulled "through the rad". As apposed to having air flowing over the engine itself.
Is that correct? :D If so, then the fan type itself is not as important as just getting a good air flow regardless of the type of set up you use. electri, dual electric, shroud, no shroud, clutch, flex.
I think a shroud will do the trick.
Thnx
 
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Right. You want to pull (or push) air through the radiator. Air flow across the engine is nowhere near enough cooling; you need to cool the coolant.

Fan type matters. A flex fan flattens out at high revs and doesn't pull as hard, so it doesn't roar so much. Does no harm because at high revs you're traveling fast and the wind blows through the radiator. But when you're in low range with the revs up and you're traveling .2 mph you can't count on the wind! So flex fans are not so good for wheelin.

A clutch fan senses air temperature and spins accordingly. Better for wheelin. A solid blade fan is the time-honored sure thing. Direct drive. That's what I have. But I've heard you can get 15 or 20 degrees cooler with a shroud. Right up there on my prioroty list. :D
 

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