FMTV fan sound?

I got the LMTV running yesterday. I completely agree with what others have posted on here, driving it is a blast! OK, some questions. Mine sounds like the radiator fan is on at all times. When you accelerate, between the turbocharger whine and the fan roar, it sounds just like a 747 taking off. Does everyone agree the fan roar is only supposed to be present when the fan is on due to cooling demand?

Mine is very quiet, only the turbo is heard until 190-200 degrees, Then the fan engages just for a minute or two.
Its air operated. There is an airline that goes into the fan clutch, right in the center in front of the fan, Not sure if the air engages or disengages it.
Check those air lines and fittings for leaks.

auctionaddict said:

Mine is very quiet, only the turbo is heard until 190-200 degrees, Then the fan engages just for a minute or two.
Its air operated. There is an airline that goes into the fan clutch, right in the center in front of the fan, Not sure if the air engages or disengages it.
Check those air lines and fittings for leaks.

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Same as what he said. Mine only engages when it gets up to temp and cycles on/off to cool as needed. I think air pressure keeps it disengaged. I say that because I can hear it release pressure right before the fan kicks in. Also, if you had some type of air leak then it would make sense to have the fan run all the time rather than not run at all.

Mine kicks on about 200 degrees. Not overly loud but you know it did.

Mine has been running all the time too - have too looks for leaks.

Check the solenoid under the PDP, to the right of the CTIS controller. That is what was wrong with mine.