1986 GM C10 excessive fan noise

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

JackBuck

Junior Member
Joined
Jun 4, 2019
Posts
3
Reaction score
0
Location
EDMONTON, AB
First Name
Brent
Truck Year
1986
Truck Model
C10
Engine Size
305
I just bought this 1986 Chev Silverado. It has a 305/3 speed Auto. It revs about 2500 at 60 MPH. The engine fan is so noisy with wind noise I can hear it over the engine. Is there away to get rid of this? I don't remember this in the past.
 

animal

Super Moderator
Staff member
Super Moderator
Joined
Jul 30, 2010
Posts
5,408
Reaction score
3,496
Location
Georgia
First Name
Lee
Truck Year
1986
Truck Model
c10 silverado
Engine Size
350ish
:welcome:
My first thought is does the truck have a "flex" fan vs a clutch fan? I had the same issue years ago when I went to the flex style fan. Much louder.
 

JackBuck

Junior Member
Joined
Jun 4, 2019
Posts
3
Reaction score
0
Location
EDMONTON, AB
First Name
Brent
Truck Year
1986
Truck Model
C10
Engine Size
305
How do you tell the difference between the flex fan and clutch fan.
 

Charlie

Mopar by Birth. Chevy by Choice.
Joined
Aug 2, 2017
Posts
1,837
Reaction score
909
Location
Euless, Texas
First Name
Don
Truck Year
1974
Truck Model
Cheyenne 10 LWB
Engine Size
350/TH350/AC/4 BBL Quadrajet
:welcome:

Standard fan (sample)

You must be registered for see images attach


Flex fan (sample)

You must be registered for see images attach
 
Last edited:

JackBuck

Junior Member
Joined
Jun 4, 2019
Posts
3
Reaction score
0
Location
EDMONTON, AB
First Name
Brent
Truck Year
1986
Truck Model
C10
Engine Size
305
No it’s a standard fan. How easy is the fan supposed to move. One way it will slip on the belt and the other way I can move it by hand.
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
If it’s direct to the water pump, it should be pretty rigid. If it has a thermal clutch, it should have some resistance to it when it’s cold. If it’s a nonthermal clutch, it should move fairly easy. Do you have a picture? Thermal clutches do have to be replaced from time to time.
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,017
Reaction score
1,808
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
My truck has the HD thermal fan clutch, and it looks like a very thick/robust version of the one shown on this page (scroll down to the truck fan clutches) https://www.haydenauto.com/Featured Products-Fan Clutches and Fan Blades/Content.aspx.

The clutch has a thermal engagement mechanism that depends on a fluid coupling. At cold startup the clutch is usually fully engaged (not sure why), and you get a signficant fan roar, and then it quiets down. If I immediately shut the engine down (still cold), you can move the fan freely and it is not moving the fan belt. As the engine warms up, the fluid mechanism in the clutch starts to engage and the fan starts to move with the belt, finally reaching a point where it runs about 80% of the belt speed. The clutch is surrounded by moving air from the radiator, so at highway speeds it should disengage (cool air) and the roar should be quieter.

Considering your colder climate, you could probably use a standard duty fan clutch and stock metal fan without any issues. Shop around for prices, but the most common brand seems to be Hayden.

I do not recommend using a flex fan, or removing the fan clutch. They are okay, but a stock fan and thermal clutch work much better.

Bruce
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,338
Reaction score
3,569
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
What 75gmck25 said. There is no downside to using a thermal fan clutch. It’s along for the ride when the airflow isnt needed, engages when the temperature goes up, and pulls more air than a flex fan ever will. Not to mention quieter than a flex fan. There is a silicon fluid in the clutch that expands when it gets hot, that engages the clutch. When the engine has been sitting awhile, all the fluid collects in the bottom of the clutch. When you start the engine the clutch is partially engages until the fluid is redistributed. That’s the roar you hear when you first start the engine
 

Snoots

Full Access Member
Joined
Jan 23, 2013
Posts
8,158
Reaction score
15,957
Location
Georgia
First Name
Roger
Truck Year
1973
Truck Model
Jimmy Sierra
Engine Size
350
I'd rather hear the mufflers at highway speeds. But that's just me.
 

Latest posts

Forum statistics

Threads
41,849
Posts
903,432
Members
33,362
Latest member
Dhatch84
Top