Radiator fan runs when engine is cold

[mlupone]

I have a 2004 Suburban Z71 with 205K miles.

QUESTION: Should the radiator fan run at initial start-up when the engine is cold?

I have never noticed whether it runs or not when you start the engine from a cold start. Yesterday, I noticed that the dashboard temperature gauge wasn't operating; e.g. the needle was sitting at/just below 160 degrees after driving for 30 min or so. I thought the engine coolant temp sensor was bad, but this morning the dash temp gauge was reading properly. I also noticed that the fan was running from a cold start. Since the fan is connected to the water pump pulley and the water pump is continuously running when the engine is operating, shouldn't I expect the fan to run continuously as well?

As an aside, the cooling system has always been properly maintained and the water pump was replaced at 150K miles.

Matt

 

[B-train]

Your truck has a viscous fan coupler. They will run when cold and should taper off after a few minutes. Then kick on when the temp rises to the point of needed airflow for cooling

 

[mlupone]

Your truck has a viscous fan coupler. They will run when cold and should taper off after a few minutes. Then kick on when the temp rises to the point of needed airflow for cooling

Thanks B-train!

 

[mattbta]

If you replace the fan clutch, go OEM. There have been numerous reports of cheaper aftermarket clutches causing the truck to sound like a freight-liner after startup. I went OEM and it was still quite noticeable. Or do an e-fan conversion.

 

[Sam Harris]

If you replace the fan clutch, go OEM. There have been numerous reports of cheaper aftermarket clutches causing the truck to sound like a freight-liner after startup. I went OEM and it was still quite noticeable. Or do an e-fan conversion.

Efan conversion 100%.. and since you’ll need a tuner to enable the fans.. I mean, you have to do a tune as well.. it’s a cheap, easy, and definitely worthwhile upgrade. And it will also give you a lot more room up front for something to assist with eh.. proper air induction..

 

[mlupone]

Thanks for the e-fan recommendation. Seriously thinking about going this route. Why would an e-fan need a "tune".

I found this on YouTube. Seems somewhat complex.

 

[Fless]

The fan will be (should be) loose on the clutch when the engine is cold, but there is always a little engagement and centrifugal force that makes the blades move. As the clutch heats up the connection to the fan tightens and it forces it to run at speed.

When the engine is cold (and off) you should be able to easily turn the fan blades. After a warm shut-down, the fan blades should be tight to the clutch and hard to move by hand.

 

[mlupone]

Here's an opinion against; e.g. e-fans are huge power hog, need bigger alternator/fuses... (per this YouTube video).

 

[Fless]

I've towed several different 4K lb campers in the Rocky Mountains (Denver to Western Slope, multiple high passes) for several years now and haven't needed the conversion to keep the engine cool. If the rest of your cooling system is good, the non-efan should work fine.

 

[Marky Dissod]

Thanks for the e-fan recommendation. Seriously thinking about going this route. Why would an e-fan need a "tune"?

If the vehicle's original fan is mechanical, then that pcm is so written - it will not bother trying to control it.
If the vehicle's original fanS are electrical, that pcm is written to control electrical fans in response to either coolant temp or AC psi.

If your pcm is 'unaware' of an electrical fans conversion, then your electrical fans will be inert -
UNLESS your electrical fans are NOT controlled by the pcm (older style conversion?)

Here's an opinion against; e.g. e-fans are huge power hog, need bigger alternator/fuses... (per this YouTube video).

1ROAD's truck is a GMT431.
Did ANY GMT400s have electric fans, or OE electrical wiring commensurate with electric fans?

Put another way: how well does this apply to GMT800s?
How many e-fan conversions had the same problems as 1ROAD with his aftermarket dual electric fan conversion?

 

[Marky Dissod]

I've towed several different 4K lb campers in the Rocky Mountains (Denver to Western Slope, multiple high passes) for several years now and haven't needed the conversion to keep the engine cool.
If the rest of your cooling system is good, the non-efan should work fine.

AT HOT IDLE RpM, the mech fan canNOT move quite enough air when the AC is most desired.
The mech fan works very well when towing because the engine / mech fan is spinning much faster than at idle.

The very temporary / repeatable intervention:
left foot on the brake, right foot on the gas, increase engine / fan RpM enough to increase AC condenser airflow and restore AC function.

GM's cheap@$$ solution:
add just enough electrical fan to blow just enough air thru the AC condenser at hot idle.

 

[Doubeleive]

If the vehicle's original fan is mechanical, then that pcm is so written - it will not bother trying to control it.
If the vehicle's original fanS are electrical, that pcm is written to control electrical fans in response to either coolant temp or AC psi.

If your pcm is 'unaware' of an electrical fans conversion, then your electrical fans will be inert -
UNLESS your electrical fans are NOT controlled by the pcm (older style conversion?)

1ROAD's truck is a GMT431.
Did ANY GMT400s have electric fans, or OE electrical wiring commensurate with electric fans?

Put another way: how well does this apply to GMT800s?
How many e-fan conversions had the same problems as 1ROAD with his aftermarket dual electric fan conversion?

It doesn't, he added a 3rd party product to a vehicle that was never designed for it as such he didn't initially do the upgrade properly. Adding oem fans to a 00-03/04 can be done easier, you may still want to upgrade the alternator in any case.

 

[Marky Dissod]

My solution for one summer (hopefully not two):
raise the Park / Neutral idle RpM settingS from 500something RpM to 750RpM in the pcm for the summer.

OE Park / Neutral idle settings were restored in the first week of September.
Hopefully I will not have to do the above again this summer.
With luck I'll be able to afford a proper '07 OE type electrical fan conversion.

 

[Marky Dissod]

It doesn't, he added a 3rd party product to a vehicle that was never designed for it.
As such he didn't initially do the upgrade properly.
Adding oem fans to a 00-03/04 can be done easier, you may still want to upgrade the alternator in any case.

Was there even an OE electrical fans option for GMT400s?

 

[Doubeleive]

Was there even an OE electrical fans option for GMT400s?

No, not that I am aware of, as far as I know they were all pulley or fan clutch up to about 03/04, there was a small oem fan that I have seen on pickups for the ac section before I have one in my garage

 

[Marky Dissod]

No, not that I am aware of, as far as I know they were all pulley or fan clutch up to about 03/04, there was a small oem fan that I have seen on pickups for the ac section before I have one in my garage

As GMT800 vehicles do have an OE solution for pcm controlled electrical fans, 1ROAD's video in this thread is useless / irrelevant to GMT800 vehicles, and should be ignored.
There, that's sorted.

 

[Rocket Man]

As GMT800 vehicles do have an OE solution for pcm controlled electrical fans, 1ROAD's video in this thread is useless / irrelevant to GMT800 vehicles, and should be ignored.
There, that's sorted.

Ok then.

 

[mlupone]

Excellent point. I don't know if any GMT800s came with e-fans. The supposition is if they did, then all GMT800s probably/or may have had the robust wiring/fuses/alternator to accommodate an e-fan upgrade. Again, I don't know...thoughts anyone???

 

[Sam Harris]

Excellent point. I don't know if any GMT800s came with e-fans. The supposition is if they did, then all GMT800s probably/or may have had the robust wiring/fuses/alternator to accommodate an e-fan upgrade. Again, I don't know...thoughts anyone???

The GMT800 had efans beginning in the ‘05 model year I believe, for the Tahoe / Suburban / Yukon / Yukon XL. They were also included in the pickups, but not sure what year it started, and I believe it also would depend on the level (1500/2500/3500)

 

[Rocket Man]

Excellent point. I don't know if any GMT800s came with e-fans. The supposition is if they did, then all GMT800s probably/or may have had the robust wiring/fuses/alternator to accommodate an e-fan upgrade. Again, I don't know...thoughts anyone???

Like @Sam Harris said, the e-fans began in 05. Prior to that, the trucks did not have the wiring or relays/ fuses for them so most of us who did the conversion used a factory harness which includes an add-on fuse panel that attaches to the side of the main under hood one. There are aftermarket ones available but they have a tendency to melt when it’s real hot outside. This harness also has a wire with the pin on it that is inserted into the PCM harness and then that output needs to be turned on via a tune so the PCM knows there’s an electric fan that it can control. There’s a good write up on it in the 00-06 tech section.

How to install E-Fans

Step 1 - Pop hood Step 2 - Remove intake tube (This is only IF you want extra space...I didnt pull mine this time but you might want to) Step 3 - Remove two top bolts and pull coolant line clip out of shroud Step 4 - The Fan Shroud is two pieces. A top and a bottom. They are connected...

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