Engine sounds like it's turning a big fan.

jonnyquest · July 19, 2006

99 Sierra 1500 (smaller v8), sometimes the engine sounds like it's turning a big fan, somewhat like a big u-haul truck. When it does it however there's no lack in acceleration or loss of fuel mileage. It's not all the time, otherwise it runs quiet and smooth.

Any ideas?

Thanks!

Jonny

Ape0r · July 19, 2006

99 Sierra 1500 (smaller v8), sometimes the engine sounds like it's turning a big fan, somewhat like a big u-haul truck. When it does it however there's no lack in acceleration or loss of fuel mileage. It's not all the time, otherwise it runs quiet and smooth.

Any ideas?

Thanks!

Jonny

<{POST_SNAPBACK}>

Um.. is it the fan spinning?

jonnyquest · July 19, 2006

Not sure if it's the fan turning, only hear it under acceleration at which time i'm not going to jump out and check it.

It will do at anytime, like when i first drive it in the morning (so it's not been sitting getting hot in traffic). But yes, i does sound like the fan is turning. Almost like the engine feels labored.

pwall · July 19, 2006

Not sure about the 99, but the 2002 has a 2 speed fan. So, when it's really hot outside, the fan is really going...much louder.

Perhaps that's what your hearing ?

Z71SierraSLT · July 19, 2006

Not sure if it's the fan turning, only hear it under acceleration at which time i'm not going to jump out and check it.

It will do at anytime, like when i first drive it in the morning (so it's not been sitting getting hot in traffic). But yes, i does sound like the fan is turning. Almost like the engine feels labored.

<{POST_SNAPBACK}>

I have a 2000 GMC Sierra SLT Z71 with a 5.3L V8

Mine does that too. The fan goes with the acceleration...lol

Not sure why it does that. No problems on it.

It just sounds like the engine/fan is working hard.

6Burgh · July 19, 2006

Not sure if it's the fan turning, only hear it under acceleration at which time i'm not going to jump out and check it.

<{POST_SNAPBACK}>

Let someone else drive while you ride under the hood.

svensk · July 19, 2006

I have it also. 2000 Sierra 5.3

asilverblazer · July 19, 2006

The fan clutch could be failing but it sounds like it is behaving normally. As the fan gets warmer from the engine temps it becomes synchronized with engine rpm (when cold it some what free wheels) so that it spins faster increasing the cooling effect when hot, and decreasing it when cool.

bigdogxx · July 19, 2006

Yup pretty much a normal thing i had the same thing with my older s10 trucks both had clutch fans.Thank god they finally grew a brain and switched over to electric fans on my 05 much better then that power robbing clutch fan setup.

ken1mod · July 19, 2006

fan clutch has probably seized. with engine off see if fan spins. if it does not turn easily, it is seized and needs replaced. get a good replacement, cheap clutches don't work

ken

jonnyquest · July 19, 2006

I hope it's not a clutch fan!

It doesn't do it all the time, but now that it was mentioned, it did it this morning and it's been hot down here in Florida past few days.

pwall · July 19, 2006

I'm quite sure what you are hearing is the 2speed clutch.

I remember when I was in Floriday a couple of summers ago, the fan was almost always in '2nd speed' (if I can use that term).

The past few days in Ottawa, it's been over 30degrees celcius (that is in the 90F I think) and my fan has been running high.

kdm101 · July 19, 2006

It's the clutch. Mine was doing it frequently as well. I pulled it off and put electric fans on instead. E-fans were definitely more expensive though.

And, yes it does suck up a lot of power at the low RPMs!

SharkRacer · July 19, 2006

It's the clutch. Mine was doing it frequently as well. I pulled it off and put electric fans on instead. E-fans were definitely more expensive though.

And, yes it does suck up a lot of power at the low RPMs!

<{POST_SNAPBACK}>

When I bought my 07 Silverado 4.8L V8, I thought it had an engine driven fan from all the fan-like noises underneath the hood. I was very surprised to find an electric fan in there.

One magnaflow muffler installed and the "fan noise" disappeared.

Shaners · July 19, 2006

It actually states in my manual that the fan may be engaged when you first start your truck and that it is normal.

Mine does it in the mornings especially if I park it in a hot garage with a hot motor the night before. Sometimes it will kick out in a block or so of driving, other times it takes several blocks.

As someone noted the older S-10's with the 4.3L were absolutly horrible!!!