overheating waiting at drive thru

[skarts]

I have a 94 , Just had the water pump thermostat,and hoses replaced around chriatmas time (impeler failed), Now with the warmer weather the truck runs hot when on line at the drive thru, sitting in traffic ect. I have the auxilary fan on on conatntly thinking it might be the temp switch not the case , once i get moving on the highway it cools down to normal. I'm getting ready to replace the radiator, but they are expensive and one shop told me that this sounds like a fan problem. Any sugestions, im leaning towards the radiator but who know. Is there a way of testing the fan clutch? any help is welcome.

 

[joey]

TESTING

If the fan assembly free-wheels without drag (the fan blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine cool. For the following test, the cooling system must be in good condition. It also will ensure against excessively high coolant temperature.

Also here is a good link for knowledge:

http://www.popularmechanics.com/how_to_central/automotive/1772922.html?page=2

 

[skarts]

I only hear a roar from the fan when I start It cold, and it quicly subsides.
Electric fan wouldn't compensate for the clutch not engaging? one is expensive the other is more expensive would hate to replace one and find out its the other........

 

[antichrist]

When the engine is hot shut it down and check the fan, there should be significant resistance to turning. If it spins freely you need a new one, which you can get at your local auto parts store. I can look up the part number if you need it.

The other thing to check is if your radiator is clogged. Either the fins with debris, or internally with cooling system crud.
For a 94, if you've never had the radiator checked out, I'd guess that's a likely problem.