Cooling System Upgrade/Replacement

[L31MaxExpress]

Do you have a spin on clutch or bolt on clutch where it attaches at the water pump?

154672 is the spin on HD GM clutch for the 11 bladed fan. I will have to dig up the clutch part number and part number for the Duramax. Always forget those numbers.

 

[GoToGuy]

The forward of radiator auxiliary fan was first installed to provide additional forced air cooling. As was controlled by temp switch in RT. Head.
Later the Auxiliary fan was controlled by , Engine temp signal and AC temp signal to provide additional condenser cooling efficiency, additionally when HVAC overpressure the Aux was switched on.
Radiators came in three widths. 20 inches , ( never seen one). Most common are 28 and 34. Most are 17 inches tall. The exception is ultra heavy duty, usually with big block. It is 20 inches tall. Using a stepped z upper cover brackets. I have in my 93. It also has three row tubes. You have to use the fan shroud made for this radiator others will not fit.

 

[1998_K1500_Sub]

Clutch: GM GENUINE 1540111
11 blade GM fan: GM GENUINE 1580739

154672 is the spin on HD GM clutch for the 11 bladed fan.

Summary:

6.5” Clutch: GM GENUINE 1540111

7.25” Clutch: GM GENUINE 154672 (heavy duty)

11 blade fan: GM GENUINE 1580739

I would get an 04ish Duramax fan and 2007 Trailblazer SS thermal fan clutch. That sucker will move air when needed. My ac stays about 55°F at idle in my Express with a slightly trimmed Duramax fan.

… the one I mention is actually the thermal version they make for it (2007 Trailblazer SS). Hayden 2851 or equivalent.

Summary:

9 blade fan (Duramax): GM GENUINE 1580690

7.4” Clutch: Hayden 2851 (severe duty)

 

[whataTRUUUCK]

Clutch: GM GENUINE 1540111
11 blade GM fan: GM GENUINE 1580739

Thank youuuuu!

 

[whataTRUUUCK]

Do you have a spin on clutch or bolt on clutch where it attaches at the water pump?

154672 is the spin on HD GM clutch for the 11 bladed fan. I will have to dig up the clutch part number and part number for the Duramax. Always forget those numbers.

Mine is unfortunately the bolt on clutch‍
Would you know the part number for that?

 

[L31MaxExpress]

Mine is unfortunately the bolt on clutch‍
Would you know the part number for that?

Which engine and year?

 

[whataTRUUUCK]

Which engine and year?

1995 gmc k2500 7.4L TBI with stock 4.10 gears

 

[whataTRUUUCK]

Clutch: GM GENUINE 1540111
11 blade GM fan: GM GENUINE 1580739

Thats the part number for the 6.5" spin on clutch. Would you know the part number for the 7.25" bolt on clutch (i.e 4 bolts holding it to the water pump)?

 

[L31MaxExpress]

The largest clutch I know of for the bolt on reverse rotation setup is 6.45", GM 1540109.