hogpuke

The 5.3 engine I bought for my '72 Chev. swap has a provision for an engine-driven fan. What are your opinions on that fan in the stock shroud vs. electric fans? Should the electric fans be computer-controlled? The harness that came with the engine may already have those leads.

garys 68

iTrader: (1)

I've got a mechanical and electric fan on my 68 corvette.
The mechanical fan moves A LOT of air and is loud at startup. My electric fan is controlled by the ecu and a trinary switch from the AC system. I do like the simplicity of the mechanical fan, but can limit coolant hoses, intake, etc in front of the engine.
One consideration if you want big dual electrics is that your original wiring may not support the current they draw. You'll probably need completely separate wiring for the fans.
On my 72 Olds, I used dual electrics, cleaner install up front.

Jesus Freak

Spal makes fans and harnesses. I personally don't like the look, noise or functionality of a mechanical fan. Electric fans are so much quieter, only on when they need to be and I actually felt a difference in acceleration when I switched to electric fans. This was on my BMW, and the acceleration difference may be a placebo effect.

FastKat

iTrader: (10)

Another thing about electric fans is that you can set them up to come on when the A/C comes on, which helps your A/C get cold and stay cold.

hogpuke

The mechanical fan would be a pretty simple option to get this swap on the road, but one consideration is like Gary said about the stuff on the front of the engine. I hope to use the existing radiator but it has the upper hose fitting on the driver's side so there will be a radiator hose running across there somewhere. Also the intake stuff. I also like the notion of the electrics for the reasons Jesus Freak stated.

hogpuke

FastKat - Is that done through the computer? No A/C yet, but maybe down the road.

hogpuke

Jesus Freak -
Do you run a single fan? I went on the SPAL site and they have a 16" fan that I'm thinking would fit the stock shroud. Or are two fans a better choice?

Jesus Freak

Im running a single 12" fan on my setup. I think single electric fans are sufficient. It depends on what you use the car for (track, street) and how hot it is where you live. Having 2 smaller fans means they wouldn't work as hard as 1 big fan. But dual fans are more of a wiring mess.

ZQ8LS1

iTrader: (3)

You will need duals if your gonna run ac.

hogpuke

The truck is used for pulling a two-horse trailer. I'll run two electric fans if that's what it takes. I was just trying to take advantage of the existing fan shroud and mechanical fan provision on the new engine.

Jesus Freak

If you're towing I'd run duals and a huge trans cooler.

Jesus Freak

You could also run a 16" in front of the radiator as a "pusher" and a 16" on the engine side as a "puller"... That's how I'd set it up if it were mine.

Bo185

The 2005 1500 up trucks/SUV's run e-fans stock. They are for the 34'' radiators. The 2500 and larger still use mech fans.

If you can fit the stock 2005-up 35'' rad. and fans run them. It will have provisions for cooling the oil and trans as well. But I would still run an external trans cooler as well.

hogpuke

I have two 21K # transmission coolers in series in front of the radiator now so there's no room for a fan in front. I like the stock two-fan idea. Don't they come as a unit, attached to their own own shroud? Maybe remove the existing shroud and adapt that one in its place? So the ECU would control those?

Jesus Freak

Corvettes have dual fans attached to a shroud.

garys 68

iTrader: (1)

For pulling a load, you might reconsider the mechanical + single electric.
The mechanical is big enough to cool a 6.2 pulling 10k lbs. Add to that a generic electric wired to the ecu, temp switch, and/or AC trinary switch will be a very strong cooling system at a very attractive price. All ecus have the capability to control a fan based on engine temp.
Stock GM trucks have the radiator outlet on the drivers side. A stock hose will work for you. If you're using a stock truck intake, you'll have plenty of intake routing clearance.
BTW, there are quite a few issues trying to get an AC request to work in a swap and turn on the fan, increase idle, etc. You're best to use aftermarket stuff.

hogpuke

Thanks for all the info Gary. Where would I mount the electric if I run the mechanical fan? There's no room in front.

FastKat

iTrader: (10)

The PCM will control the fans if you want it to. That is how I wired mine. Some guys prefer to do it the old fashioned way and use coolant temperature switches, which is fine too. Either way, you would need to setup a couple relays to properly run a set of dual fans.

With the A/C, it depends on what year/make/model your engine and PCM are from. In some vehicles, the A/C can easily be wired through the PCM. In some vehicles, it is almost impossible to have the PCM control the A/C functions.

What year/make/model is your PCM and engine from?

garys 68

iTrader: (1)

Electric puller fans work better. You can mount it inside the shroud on the back of the radiator.
I chose the mechanical + electric because I had problems with my 68 SBC corvette running hot. The addition of of a $50 Oreileys puller fan helped a lot. When I went over to the LSx, I used the LS mechanical fan and reused the electric. Even on 100 degree days, AC blowing full, stuck in heavy traffic, temp gauge never moves.

Bo185

They come as a unit that bolt to the radiator. You should beable to find some used. You can get a new stock 34'' rad. for pretty chaep. And they are bigger then F-body/vette units. If you can fit the truck rad. I would run it. Its pretty big.

You mean Rad inlet is on drivers side.