11 blade Fan Swap on TBI350

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Hoplite

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Hey gents,

I finally got around to swapping out my stock 5 blade fan for a “plastic” 11 blade. This is on a 95 C2500 with a TBI 350.

For future reference, it fits great. The only thing that kind of sucks is it’s a pain to install because there’s not a gap between the blades for your arm.

It is a little quieter but more or less has a different less monstrous pitch to it. It seems my AC is cooling off at idle much better. My daughter didn’t know I had changed anything and mentioned it felt like the truck was cooling off allot quicker on her first ride with the new blade.

The picture (attached) really shows the difference between the fan blades.

In general though, my fan seems to stay on way too long, even with a brand new “non-heavy duty” fan clutch. I’m not sure why that is and it’s been something I’ve been tracking for about 2 years with several different replacements.

Here’s the link for the fan blade if anyone is interested in doing the same.

Dorman 621-515 Engine Cooling Fan Blade Compatible with Select Cadillac / Chevrolet / GMC Models https://a.co/d/4uxTe79
 

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L31MaxExpress

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Hey gents,

I finally got around to swapping out my stock 5 blade fan for a “plastic” 11 blade. This is on a 95 C2500 with a TBI 350.

For future reference, it fits great. The only thing that kind of sucks is it’s a pain to install because there’s not a gap between the blades for your arm.

It is a little quieter but more or less has a different less monstrous pitch to it. It seems my AC is cooling off at idle much better. My daughter didn’t know I had changed anything and mentioned it felt like the truck was cooling off allot quicker on her first ride with the new blade.

The picture (attached) really shows the difference between the fan blades.

In general though, my fan seems to stay on way too long, even with a brand new “non-heavy duty” fan clutch. I’m not sure why that is and it’s been something I’ve been tracking for about 2 years with several different replacements.

Here’s the link for the fan blade if anyone is interested in doing the same.

Dorman 621-515 Engine Cooling Fan Blade Compatible with Select Cadillac / Chevrolet / GMC Models https://a.co/d/4uxTe79
To me it sounds like you are comparing your new clutch to a worn out clutch that was getting a bit soft. When my 97 was new the clutch would be fully engaged on a hot day and stay that way for a long time even getting to speed. The temp would climb and after several complaints from us about the fan noise, hot running and poor ac output around town, the GM field engineers had the dealership put the 11 bladed fan and matching tow package clutch on it. It did make a big difference.
 

evilunclegrimace

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pennsylvaina
Hey gents,

I finally got around to swapping out my stock 5 blade fan for a “plastic” 11 blade. This is on a 95 C2500 with a TBI 350.

For future reference, it fits great. The only thing that kind of sucks is it’s a pain to install because there’s not a gap between the blades for your arm.

It is a little quieter but more or less has a different less monstrous pitch to it. It seems my AC is cooling off at idle much better. My daughter didn’t know I had changed anything and mentioned it felt like the truck was cooling off allot quicker on her first ride with the new blade.

The picture (attached) really shows the difference between the fan blades.

In general though, my fan seems to stay on way too long, even with a brand new “non-heavy duty” fan clutch. I’m not sure why that is and it’s been something I’ve been tracking for about 2 years with several different replacements.

Here’s the link for the fan blade if anyone is interested in doing the same.

Dorman 621-515 Engine Cooling Fan Blade Compatible with Select Cadillac / Chevrolet / GMC Models https://a.co/d/4uxTe79
Rockauto has a genuine GM fan for $41.89.
PN 1580739
 

eXo0us

Newbie
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Apr 1, 2023
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I still got the 5 Blade and where thinking about plastic 11 blade.

But I don't have any overheating issues and my mechanical fan hardly ever runs.
Even when towing - but I've added a electric pusher fan to the front of the radiator package - which runs as soon as I turn on the A/C (I'm in Florida - so that's always)

Did you guys notice any change in MPG from the metal to the plastic fan?
I read that it pulls more power from the engine (moves more air)
 

454cid

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I haven't driven the truck regularly enough or checked the mileage often enough to have a chance of noticing any difference with the 11 blade fan, as far as fuel economy.
 
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