2-Part Cooling Question

[stexag]

My truck has some modifications made by the PO that lack completion. One centers around the cooling system and I need to complete the work but I'd like to ask your advice first.

My truck currently doesn't have a shroud. I acquired my truck over the winter so it has not been a huge issue even after I added the VA a/c, but I live where it is starting to get HOT and my temp gauge shows it. (383 SBC, TH350, C-10, '69) I'm not getting the engine HOT yet, but we've had days in the low 90's that give me reason to think when we get 100 plus I will get pretty close to the red. I have to have a shroud or make another significant change.

Here is Question 1: My front crossmember is out of a 73-87 truck. The top of the fan is just about dead even with the top of the radiator. Is that where it is supposed to be? I'm asking before I order a shroud just in case the crossmember changed the attitude of the engine and I should be looking for an alternate shroud. I'm sure some of you have experience with this.

Question 2: It's hot here in south Texas. Does changing to electric fans make a significant difference in cooling? I would gladly do so if it would mean the engine would run cooler. I see people upgrading but I don't know if it's to gain cooling efficiency or other reasons. Is an electrical system upgrade necessary to add a double 12" fan kit?

Thank you.

[Zable49]

Stexag.... For my two cents, I would have to say that your crossmember should be just fine. As for the shroud, yes I should run one however even not having one you shouldn't see the red line. I never seen the red line with my old '64 and I didn't run a shroud but I did have a full time fan mounted on it. I am guessing you are running a clutched fan; is your clutch engaging?

As for the second question, I love electric fans as long as I run them with something like this: Summit Racing Wiring Just remember to run one that has enough CFM (2100 or more).

Well that is my 2 cents. Hope it helps

[Lattimer]

I went to electric fans just to clean up the engine bay and get rid of the potential flex fan failure. Did a dual fan setup from Jegs.

[WIDESIDE72]

Definitely install a shroud. A stock clutch fan is fine as long as the clutch is good. You can test it by putting a piece of masking tape from one blade to the shroud. Drive the truck a while til it warms up. The fan should have engaged and broken the tape. If not, time for a new clutch.

Also, are you certain your radiator is in good shape and not clogged? Same goes for hoses. Be sure they are not soft and the suction side isn't getting pulled flat by the pump.
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[in deep 72]

Even if you run electrics, you should have a shroud. I put a new aluminum 3 core radiator in with dual 12" electric fans mounted right to the radiator. I've had an overheating problem ever since (running a strong 468BB). After talking to some big block drag racers they told me to get a shroud. The fans mounted to the radiators will pull air through only where they are located when your not moving, the rest of the radiator will do very little cooling. A shroud will make them pull through the whole radiator. That was my project for the weekend. Making an aluminum shroud and switching to 16" fans.

[Lattimer]

Originally Posted by in deep 72

Even if you run electrics, you should have a shroud. I put a new aluminum 3 core radiator in with dual 12" electric fans mounted right to the radiator. I've had an overheating problem ever since (running a strong 468BB). After talking to some big block drag racers they told me to get a shroud. The fans mounted to the radiators will pull air through only where they are located when your not moving, the rest of the radiator will do very little cooling. A shroud will make them pull through the whole radiator. That was my project for the weekend. Making an aluminum shroud and switching to 16" fans.

The electric fans I put in had a shroud built into them. They cover about 90% of the radiator with the shrouds. I have a small strip top and bottom that are outside the shroud.

[stexag]

Thanks for the advice. I just put on a new clutch this week because I suspected it was part of the problem. I knew I needed a shroud, I just wanted to verify that the crossmember swap didn't preclude me from using the factory shroud... or that I shouldn't just ditch it all and go to electric fans.

I have inspected the radiator and it is in good shape and the hoses are new, so I'm going to order a shroud and give it a shot. Thanks.

[Shyguy]

When you put the shroud on you need to make sure that the fan fits at least half way into the opening.

I bought a '75 that had a different engine in it and the fan is outside the shroud. The engine runs cool enough when the truck is moving, but when it is setting still and running it starts to get pretty warm.

I put a set of of electric fans with a shroud from Summit on a '92 with a 454 and for some reason which I could not figure out the stock clutch fan kept it cooler.

If you go with electric fans you will need a higher output alternator.

[MikeyMan]

Originally Posted by Shyguy

When you put the shroud on you need to make sure that the fan fits at least half way into the opening.

I bought a '75 that had a different engine in it and the fan is outside the shroud.

Changing your crossmember and/or the position of your motor could create an issue where your fan ends up. Also, long water pump vs. short water pump. If your fan is too far from the radiator, it might not pull enough air to keep the temps down.