Radiator Fan Does not Spin Very Fast

[Kevin Donahue]

Hello,

Took the humvee out for a drive around the neighborhood today and noticed temps over 240 (on the temp gauge anyway).
I went ahead and popped the hood and noticed my fan appeared to be freewheeling so I did the usual of unplugging the TDM to see if it really was not spinning. I could visually see the fan clutch move a bit but the fan didn't really come on very hard.... definitely not any kind of "roar" or anything.

Thinking that maybe my clutch is not fully engaging and I need to whack it with a mallet or something, what do you guys think?

Also I am assuming I'm not really rolling around with like 250-260 degree water temps but I dont know. This is a project humvee and I drove it home from my shop the other day with gauges unplugged (dumb I know) and it didn't even seem hot. I've also let it idle for 20 minutes in 90 degree weather the same thing, nothing to indicate its running hot... if this thing was really skyrocketing over 240 degrees, probably more like 250-260 in these hot temps I would guess there would be some kind of boil-over if not a killed motor correct? Or can diesels get crazy hot and it not be obvious?

Gonna get a temp gun soon to confirm actual water temps.

 

[frank8003]

The temperature gun is your savior
One can my fiqure out al kinds of stuff with one.
Nobbody on SS should be without a termperature gun.

 

[Kevin Donahue]

The temperature gun is your savior
One can my fiqure out al kinds of stuff with one.
Nobbody on SS should be without a termperature gun.

10-4 good buddy

 

[fpchief]

If I unplug mine at idle, there is a speed difference but no sound. Gotta be at some RPM to really hear it. Unplug and rev it. However, you said you have driven it around so I am sure you would have heard it if engaging all the way. Interested in seeing what the temp gun says.

 

[Andyrv6av8r]

Unplug it, drive it several miles then see if the temperature changes.

 

[Kevin Donahue]

If I unplug mine at idle, there is a speed difference but no sound. Gotta be at some RPM to really hear it. Unplug and rev it. However, you said you have driven it around so I am sure you would have heard it if engaging all the way. Interested in seeing what the temp gun says.

Update- temp gun actually only ready about 185. I changed out the gauge and operating temps for me are about 205 - 220. Much better lol... only issue now is the fan seems to run almost constantly on the highway and anything over 40 MPH. Time to start replacing parts and hoping for the best.

Thanks guys for the help!