Heavy duty or severe duty fan clutch?

[ColoradoSilverado]

How can I tell which one I need? Or are they interchangeable?

Thanks

[MT-2500]

Originally Posted by ColoradoSilverado

How can I tell which one I need? Or are they interchangeable?

Thanks

Depends on what rear end and with or without trailer tow package.
Post that info back or.
Check with your parts place or have dealer run vin no.

[ColoradoSilverado]

I have the towing package but never been able to figure out my rear end, I know it's one of the codes on the sticker in the glove compartment right?

[ColoradoSilverado]

My rear axle ratio is 3.73

Bert

[777stickman]

I would think that with a 5.3 the heavy duty would be fine. Severe duty would be more for a 3/4 ton or 1 ton truck with a big block motor.

[j cAT]

Originally Posted by ColoradoSilverado

How can I tell which one I need? Or are they interchangeable?

Thanks

if you get a fan clutch that has a higher amount of locking you will use more fuel. it will put a load on the engine.

the best way to reduce heat load would be to install a very large tranny cooler in front of the condensor . this will reduce the heat input to the engine and increase cooling capacity of your coolant system with no loss of pwr/MPG.

if the fan clutch is defective replace with the same OEM type.

[ColoradoSilverado]

Went to Advance Auto parts and got the severe duty anyway, I doubt I will notice a difference in power and MPG between the Heavy duty and Severe duty. Thanks all for your input! It's been hot here, we had a week of 100's and high nineteens for the past couple of weeks.

[danielsatur]

It's all about keeping coolant, and transmission cooler under a load, the MPG isn't a factor.

[suburbanstevie]

Can I ask what is prompting you to replace the clutch? Over-heating, loss of fluid in clutch, etc..?

[danielsatur]

Had a thermomatic fan clutch go bad, anything over 65MPH would cause her to overheat. A good mechanical fan clutch resolved that problem.

[ColoradoSilverado]

Originally Posted by suburbanstevie

Can I ask what is prompting you to replace the clutch? Over-heating, loss of fluid in clutch, etc..?

My truck has been overheating lately, I did the "manual" test according to my Haynes manual and concluded that fan clutch was bad. Doesn't surprise me after 238.000 miles.......

[danielsatur]

Also clean road grime + bugs in front of both the air condition condenser and radiator.

[j cAT]

Originally Posted by danielsatur

Also clean road grime + bugs in front of both the air condition condenser and radiator.

for those out there following this running hot issue. this is what I have found over the years.

if the vehicle only runs hotter below 40 mph then this is the fan clutch or the electric fans.

if the vehicle over heats also above 40 mph then this would be a cooling system failure.

items like coolant pressure cap,water pump impeller corroded to stubs,bad thermostat,coolant leaks,head gasket / exhaust gases in the coolant,coolant passageways clogged with mixing different coolants with dexcool..

with operating at a high elevation coolant system pressure must be 15 psi. if the coolant is allowed to boil at 190 degf because of a high elevation operation this would also do it with 90deg f plus temps.

this vehicle should operate at 190 deg f. temp should not change . once it hits 190 thats it.............if it starts to climb you got trouble .

[ColoradoSilverado]

Well, the last couple of weeks temps usual stayed around one quart of the Temp gauge for a long time and then went up to three quarter, today after installing the new fan clutch, it went to around 190 and stayed there! Thanks all!