Gizmo97

This thread is for all those who believe that their fan clutch is going bad. If your fan sounds like a jet engine on take-off while you are increasing speed and your check-engine light is on, your fan clutch may have to be changed.

In order to change the fan clutch, what you first need to do is purchase a new fan clutch; it appears that only the dealer is selling them. I purchased mine for approximately $265.00. You also need two wrenches: one large enough to go over the four bolts of the water pump, the other (could be a large adjustable) to go over the nut that screws over the shaft. I got mine from Autozone, free of charge. They only need a deposit, which they later reimburse.

To do the job takes about one hour or less. Using a half-inch wrench, remove the four bolts holding the fan blades to the fan clutch. With the larger wrench, hold the four bolts from the water pump while unscrewing the large nut from the fan clutch with the other wrench; it is a regular thread, so it unscrews counterclockwise while viewed from the front. It is a little tricky to take out the fan clutch between the fan shroud and the radiator (I removed the two bolts from the fan shround in order to give me more play). Put the new clutch in place and screw the nut into the shaft clockwise. When everything is finished, you'll take a ride and be very pleased that the awful noise has dissapeared. It takes 10-15 times of starting and stopping the car for the check-engine light to go out.

Hope I was helpful and saved you a few bucks. Good luck.

-Gizmo

potts200

Can you give any more details about how you maneuvered the fan and clutch out? I couldn't lift the clutch out while my arm was in between the shroud and the fan. Did you drag the clutch out by the cable instead of holding it? Had a heck of a time getting the plastic tabs squeezed together to release the cable at the top of the shroud. The one peice shroud is a ridiculous design. Any insight you provide will be great!

kuntrytrucker

I have a 2002 trailblazer and the computer gives me a diagnostic code of 1481 i've replaced the fan clutch and its still makeing a jet engine noise. Its comming from the front of the engine and i'm at a loss to figure out what is it. Anyhelp would be greatly appreciated.

kuntrytrucker

maxwedge

There are some software updates for the fan clutch issue.

ScarabEpic22

Yeah, make sure if you replace the fan clutch that you use the new part number as well as update the PCM software.

__________________
-Erik

2002 Chevrolet TrailBlazer LT 4X4 -Summit White w/Oak interior
Many Mods, latest: EFILive tuned by (me)

potts200

Just wanted to write this up for the novice mechanic like myself and anyone else who might find it useful. My first attempt to replace the fan clutch on my ’02 Trailblazer failed because I wasn’t patient. These steps and observations are what worked for me and in no way represent the best way to accomplish this job. The original post by Gizmo97 has great information but I wanted to add a few more details; it was that post that convinced me I could do this job.
First, I found that the tool for rent from O’Reilly Auto Parts worked well for me. I was able to hold the water pump by the bolt heads and the smaller of the two wrenches that came with it was an exact fit.
I loosened the fan clutch nut from the water pump first using the tool but did not completely unscrew it. The nut has normal threads so to loosen it, turn the nut counter-clockwise. Next, I removed the four bolts holding the fan to the fan clutch and pushed the fan against the engine block. This allowed me clearance to put some cardboard between the clutch and the radiator and avoid bending radiator fins. I also removed the cable harness from the top right of the fan shroud. Removing the top left and right bolts holding the shroud in place allowed me to pull it up about a half inch; every little bit counts. I completely unthreaded the clutch at this time but because of the tight space I was not able to gracefully pull the clutch off the water pump; it fell to the bottom. At this point the clutch is sitting below the water pump but still in close quarters with the fan. The idea now is to pull the fan out first. To accomplish this hold the clutch flat against the radiator and maneuver the fan; the hardest part is getting the nut past the rim of the fan. The top of the shroud will flex a little as do each of the blades on the fan and this allows the fan to be removed. You may have to rotate the fan to get it past the water pump bolts but it will come out. Also, it is a tight fit around the top left side of the fan; I want to call this part the valve cover but it isn’t. I will call it the oil fill area. I had to bend the fan blades to get past this point. Once the fan is out, the clutch can come out very easily. The installation of the clutch is the exact opposite of removal. Don’t forget to pull out the cardboard!
Hope this makes the job easier for someone. Saved a boatload of money by trying it myself so it was worth the trouble. Lowest quote I got from a dealer was $700 with $331 going for the clutch. Spent $194 for the updated clutch, rental tool was free, and I still have to take it to get the PCM updated for $40 but still significantly cheaper. Good Luck!