Gets hot after adding shroud?

[Markmartin01]

So I have a 91, 350, pretty run of the mill truck. Converted to 16" electric fan a couple of years ago after the water pump mount sheared and about threw the mechanical fan through my face. Cooled fine at speed without a shroud, wants to get hot after driving on the freeway and pulling off. Thought it was the lack of shroud so I made one from thin gauge. Made it 5 miles with the shroud and it's getting hot. Fan seems to move a ton of air. But why would adding a shroud make it get hot at slower city speed where it didn't without a shroud at all? Thoughts?

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[Dropped88]

That shroud is covering a lot of the surface area. Basically making your radiator smaller.

These trucks are better suited for 2 fans if your going electric.

That would take care of the idle/low speed problem.

But your initial issue does it get hot and you pull off the freeway? or is it not getting hot till your pulling off the freeway?

 

[BeXtreme]

Those dinky little flex-o-lite style fans do not flow a lot of air. Also that shroud is blocking a ton of airflow through the radiator. I have dual electrics from a 2007+ 2500 pickup on my 1980 K25 with a 1997 K2500 7.4L radiator... the fans barely need to even come on unless I'm sitting idling for a long time. Then they only come on for a few seconds before it pulls the temps back down far enough to shut them back off. Low speed comes on when AC is on and high speed is triggered by the temp switch in the passenger side head.

 

[kennythewelder]

Air flow. Your not pulling enough air through the radiator for it to cool the water off. Adding that shroud, just made it worse. You restricted more air flow. For our trucks, you really need 2- E fans. 1- E fan, just really isn't enough. Here is the write up on my E fan swap.Thread 'Electric fan swap, on the cheap' https://www.gmt400.com/threads/electric-fan-swap-on-the-cheap.41756/

 

[BeXtreme]

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Here’s a pic of it mocked up on the radiator and core support before it went in the truck. It was only $50 for the fans at a local junk yard. New wiring pigtails were $10 on Amazon.

It has no problem keeping this big old truck cool even with AC blasting, pulling a trailer through the mountains in this big old truck.

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[L31MaxExpress]

Put a clutch fan back on it with more than the factory 5 blades. 11 bladed GMT400 tow fan is a bolt on. Good old clutch fan will never run hot.

 

[L31MaxExpress]

Those dinky little flex-o-lite style fans do not flow a lot of air. Also that shroud is blocking a ton of airflow through the radiator. I have dual electrics from a 2007+ 2500 pickup on my 1980 K25 with a 1997 K2500 7.4L radiator... the fans barely need to even come on unless I'm sitting idling for a long time. Then they only come on for a few seconds before it pulls the temps back down far enough to shut them back off. Low speed comes on when AC is on and high speed is triggered by the temp switch in the passenger side head.

Here in Texas those fans would be screaming on high and the engine would be near overheating.

 

[BeXtreme]

Here in Texas those fans would be screaming on high and the engine would be near overheating.

False. I've been out driving it at 100 degrees ambient with the AC blasting while sitting in stop and go or in a line for 20-30 minutes and it still barely engages the high speed fans. Maybe 10 seconds every minute or so. Usually since the low speed stays on when the AC clutch is engaged, it is plenty to keep it cool on it's own. I don't think I've ever even seen the high speed engage while I'm moving at any kind of speed above about 25mph. The idea that driving around in 100 degree temps in flat level ground texas, but not have any issues in 100 degree weather pulling steep mountain grades is laughable.

They are the same fans that we have on our 2011 Suburban and that thing has HALF the radiator that this does. We towed our travel trailer over the Sierras and up through Yosemite and Southern California last year and it was well over 100 degrees the entire way. 11% grades at 7,000ft and zero issues.

I think most of the issues I see people have with electric fans is related to either improper electrical wiring, poor fitment(i.e. fan shroud mismatch), or engine cooling problems(i.e. wrong thermostat, undersized radiator, etc...)

 

[L31MaxExpress]

False. I've been out driving it at 100 degrees ambient with the AC blasting while sitting in stop and go or in a line for 20-30 minutes and it still barely engages the high speed fans. Maybe 10 seconds every minute or so. Usually since the low speed stays on when the AC clutch is engaged, it is plenty to keep it cool on it's own. I don't think I've ever even seen the high speed engage while I'm moving at any kind of speed above about 25mph. The idea that driving around in 100 degree temps in flat level ground texas, but not have any issues in 100 degree weather pulling steep mountain grades is laughable.

They are the same fans that we have on our 2011 Suburban and that thing has HALF the radiator that this does. We towed our travel trailer over the Sierras and up through Yosemite and Southern California last year and it was well over 100 degrees the entire way. 11% grades at 7,000ft and zero issues.

I think most of the issues I see people have with electric fans is related to either improper electrical wiring, poor fitment(i.e. fan shroud mismatch), or engine cooling problems(i.e. wrong thermostat, undersized radiator, etc...)

I had the same fans, they would not keep my engine cool. My radiator was a 454/8.1 core. Ambient air in bumper to bumper is 118F at the moment, its 109F in the shade. Who said Texas is level?

 

[1998_K1500_Sub]

"Electric" fan: I would pay good money to see someone retrofit one of the electric clutches, to one of the GMT400s.

Here's Hayden's selection:

EVC Manufacturing

www.haydenauto.com

The Chevy Trailblazer used an electric fan clutch (and presumably GMC / Saab / Oldsmobile / Buick / Isuzu cloans) on some (all?) of its engines. It had the 4.2L I5 and the 5.3L V8, right? Was the "SS" a 5.3L too?