Modifying Thermal Fan Clutches

Re your original question I have never adjusted one. I did not know it could be done. 

I played with the SD clutch some when I got home. Took the spring off, rotated the center post to make sure it was free, then reinstalled the spring. I heated the spring with a grill lighter. From full cold to full hot it turned less than 1/4 rotation. 

In a system where 1/4 rotation is the difference between open and closed, I can't see how a full or half rotation of the center post could make a difference in how it opens.

In other news the local supplier said I can buy the third clutch directly but I'd have to pay list, which is 2x rock auto price. So I'm about to order something on line that is sitting in a store less than 10 miles from me....because it costs half as much and ships for free. And that is how retail dies ladies and gentlemen. 

For those saying the fan is crutching another issue: it kinda is, but not one that can be easily fixed.  ZJs have horrid airflow through the front end without the big clutch fan helping them. 

A thicker rad will make more use of the air that does get through and help cooling some, but short of cutting up the hood, etc. a ZJ will never really cool well without a mech fan and a good clutch. 

rslifkin said:

For those saying the fan is crutching another issue: it kinda is, but not one that can be easily fixed.  ZJs have horrid airflow through the front end without the big clutch fan helping them. 

A thicker rad will make more use of the air that does get through and help cooling some, but short of cutting up the hood, etc. a ZJ will never really cool well without a mech fan and a good clutch. 

Speaking of, you'll get a kick out of this...I was driving in the rain last week and the holes I cut in the hood were moving enough air to create visible columns of  vertical spray about a foot tall. Looks like the factory knew what they were doing putting the niner vents in that location.

I've got a picture somewhere of the hood on my niner after a salty, dirty highway drive in the winter.  There are 2 clean stripes down the hood from the vents going 90% of the way back to the windshield and then off the sides.  Everywhere else on the hood was filthy.