Thermal fan clutch operation

[Jim_PA]

I was breaking in a new cam today, and at start-up, of course the fan was locked for the first 20-30 seconds. It disengaged, and stayed that way... Engine temps crawled up to 210, and the clutch never got tight.

Is it because I was just sitting in the garage with RPM's up, and no hot air moving?

I would have thought that just sitting there, things would have been hot enough for it to start working...

Maybe time for a new one? This one only has a few thousand miles on it.

Thanks

[Stocker]

Good question, and I didn't know what the lockup temperature typically is. I just found this:
Fan clutch should engage at approximately 190-195 degrees F. coolant temperature
http://www.delpprintingandmailing.co...FDs/SB1004.pdf
If you believe your gauge, the clutch may be bad... or maybe yours is just calibrated to kick in at a bit higher temperature.


Edit: A bit farther down the page, it also says:
Fan clutch engagement is not required until the vehicle is under a load for some 7-10 minutes in 70+ degrees F. ambient temperature

[Stocker]

I also just found a troubleshooting guide for fan clutches, might be helpful to someone... I'm gonna bookmark it.

http://www.justanswer.com/questions/...gine-workhorse

[Jim_PA]

Originally Posted by Stocker

Edit: A bit farther down the page, it also says:
Fan clutch engagement is not required until the vehicle is under a load for some 7-10 minutes in 70+ degrees F. ambient temperature

ok, so being that it was 60 deg. Here today, and I only ran it for 10 minutes, maybe the clutch is fine. I guess I should have had a big fan as already suggested to me by someone earlier. The operating principles make it a little tricky for cam break-in, and for that matter, extended warm-ups in the winter.